Discuss Changing original 32Amp contactors for solid state relays? in the Electric Underfloor Heating Wiring area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:  American Electrical Advice Forum

Hi Guys,

My underfloor heating has 3 x 32amp contactors. They make a hell of a thump when opening and closing. Bit of a hum also.

I'm looking at the idea of changing them for solid state relays like this one Solid State Relay - 40A (3-32V DC Input) - COM-13015 - SparkFun Electronics - https://www.sparkfun.com/products/13015

Will these work? I'd need to source a 12v switching supply instead of the current 220v. Easily done as I have plenty of 220-12v power supplies handy.
I assume they are much quieter and can be switched endless times without any physical parts wearing out.

Thanks in advance
 

Lucien Nunes

-
Mentor
Arms
Esteemed
In theory, yes. You can also get types with 230V AC control input. Depending on the current they are switching, a heatsink may be required as unlike a contactor, there is a small voltage drop across the power device that results in some heat dissipation (although, there's no heat dissipation from the control side as there is in a contactor coil.) Read the data sheet. Depending on the supply voltage, likelihood of voltage spikes and the nature of the load (yours is resistive and therefore should be tame) snubbers and/or transient voltage suppression might be recommended.

My experience with power semiconductor devices is that you get what you pay for. I don't know about the particular product in your link but an industrial SSR of that rating, that I would be happy to rely on, is typically more expensive.
 

marconi

-
Mentor
Arms
Esteemed
You might want to investigate 'silent contactors' to replace your present ones. Here is an example:

amazon" style="max-width:120px">Amazon productView: https://www.amazon.co.uk/Hager-Esc440s-Silent-Contactor-40a-4no-230/dp/B0062X1D2I


These use the usual mains supply voltage to power their coils. Other manufacturers make them too. You may still hear briefly the closing or opening events but once closed they are quieter than normal types.
 
  • Thread Starter Thread Starter
  • #4
You might want to investigate 'silent contactors' to replace your present ones. Here is an example:

Amazon productView: https://www.amazon.co.uk/Hager-Esc440s-Silent-Contactor-40a-4no-230/dp/B0062X1D2I


These use the usual mains supply voltage to power their coils. Other manufacturers make them too.
Thanks .

That's the one I have for the upstairs floor heating.
Yes it is silent. 40 amp model for all the heating upstairs.

Downstairs we have 3 contactors of 32 amps each but I don't think they consume more than 5000 watts in total. (230v).


5000 watts would be 22 amps in total. hmmm why have 3 x 32 amps? (maybe just what they had and the max amperage is not that important)
Wouldn't one or 2 of these be sufficient in the placement of the 3 noisy contactors?

Also the power prior to the contactors come from 3 x 20amp trip switches.

Thanks for the replies today
Post automatically merged:

I see the types of heat sinks available now.

Amazon productView: https://www.amazon.co.uk/SSR-40-3-32V-24-380V-Solid-State/dp/B07JQ2S3Z9/ref=pd_sbs_328_6/259-1440324-8968235?_encoding=UTF8&pd_rd_i=B07JQ2S3Z9&pd_rd_r=2d4cd923-0e7c-478f-b7a4-b92b29eeb364&pd_rd_w=87mxm&pd_rd_wg=XGJ4t&pf_rd_p=2773aa8e-42c5-4dbe-bda8-5cdf226aa078&pf_rd_r=X4E4Y1A3XRD1EP9X00WG&psc=1&refRID=X4E4Y1A3XRD1EP9X00WG


I wonder is 16 amps through a 40amp version will keep cool without a heatsink?
 
Last edited:

marconi

-
Mentor
Arms
Esteemed
A wiring drawing and some pictures would be helpful plus exact numbers for the Ipower of under floor heating pads, cables, tiles. Please include the thermostats. This will help folk advise you.
 
  • Thread Starter Thread Starter
  • #6
Here we have the ground floor contactors. 4 thermostats (cheap copies of Honeywell and do not work well at all). Installing a central digital thermostat that will send a signal to the sonoff switch in the fuse box.

Living room
Dining room
Breakfast room and kitchen (2 zones).

Living room about 11-12m2 consumes about 2000 kwh.
Dining room a little less and kitchen/breakfast about 1800 combined.

No more than 6000 kwh. (230v)

Would it be possible to swap out the 3 contactors here for 1 x 4 pole new contactor? How would this be wired? You see we have 2 Lives/ 1 Neutral cable set up coming in.
I see 3 sets of L/N cables going out to each of the 3 zones. I recently added the meters.
 

Attachments

marconi

-
Mentor
Arms
Esteemed
Could you take a couple more photos? One looking down on the black bar across the top of the 20A circuit breakers and one looking up to the contactors, timer and power meters?

It looks to me that the power meter and the time switch are unused - am I correct?

The wiring looks somewhat quirky so the extra photos will be helpful.

Who wired this up?
 
  • Thread Starter Thread Starter
  • #8
Many thanks Marconi. Appreciate your time.

The timer on the right is now unused. Just the L/N being taken from the inputs to power the Sonoff R3 wifi switch on the left that I added this week to control the contactors. Much easier to set times and control virtually.

The 3 slim power meters I added are in use as I'm currently calculating the costs and making notes of daily use. They are wired in between the 20amp breakers and the contactors. (They are upside down as the inputs were on the bottom oddly). Sorry the double cabling (2 x 2mm) was used on the meters as I did not happen to have any 3mm in the house. I'll get around the changing those and making it all neater once the lockdown is over.

The original wiring with the breakers and contactors was all done by the underfloor heating company 'EuroCable' 10 years ago when the house was constructed.

Struggled at first to figure out the L1/L2/N 3 wire cabling config.

Thanks again
 

Attachments

Last edited:

marconi

-
Mentor
Arms
Esteemed
Sir- could you tell me please what qualifications and experience you have with this type of wiring and electrical accessories?

What I am seeing looks 'confused'. For example the power meters look to be wired across the 20A circuit breakers. The wiring arrangement of the top row of disconnector and 5 circuit breakers is as I said before quirky. And I cannot fathom why you reckon you have an L1, L2 and N power supply. There are other anomalies.
 
  • Thread Starter Thread Starter
  • #10
Sir- could you tell me please what qualifications and experience you have with this type of wiring and electrical accessories?

What I am seeing looks 'confused'. For example the power meters look to be wired across the 20A circuit breakers. The wiring arrangement of the top row of disconnector and 5 circuit breakers is as I said before quirky. And I cannot fathom why you reckon you have an L1, L2 and N power supply. There are other anomalies.

No qualifications but many years experience of building valve amps/rebuilding transistor amps, home electrics also over the last 20 odd years.

The output of each 20a circuit breaker is wired to the meter and the output of the meter goes into the contactor.

The original cables (The thick white and brown cables) that were between the 20a breakers and contactors were just swapped over to the power meters inputs - nothing changed there.

230v, 209v, 23v - readings from ground to main cabling entering the main breaker.

Thanks
 

marconi

-
Mentor
Arms
Esteemed
What is that black bar along the top of the 5 cbs? It looks like it connects together the top five terminals and is supplied by 3 white wires from under the disconnector connected to its terminals N, L1 and L2.

And a thin Blue (neutral) connects to the underneath terminal of the second from right cb which seems odd to me.

Could you point out to me the main neutral entering and being distributed please?

Are those five cbs double pole types?

Where did you measure those voltages you mentioned in #10?
 
  • Thread Starter Thread Starter
  • #12
ok adding some original photos here of the previous original wiring.
Post automatically merged:

What is that black bar along the top of the 5 cbs? It looks like it connects together the top five terminals and is supplied by 3 white wires from under the disconnector connected to its terminals N, L1 and L2.

And a thin Blue (neutral) connects to the underneath terminal of the second from right cb which seems odd to me.

Could you point out to me the main neutral entering and being distributed please?

Where did you measure those voltages you mentioned in #10?
What is that black bar along the top of the 5 cbs? - Not sure that was original - appears to apply the power across all 5 cbs from all 3 cables as if they are all live. Yes from the 3 white wires from the main breaker.
I have the same upstairs.

That small blue wire suppliers the Live/positive to the timer.
The 3rd white cable coming into the main breaker is the one with 23v to ground. I haven't gotten my head around the 3 cable config yet. You can see they've used the small white wire from the final 20a breaker to supply the neutral for the timer.

I measure those voltages from the ground bus to the 3 main contacts on the 1st main breaker top left.

Original timer on the right was connected from the bottom outlets to each contactor. I removed the outputs as I have the sonoff now on the left.

Hope this helps. If you need more photos/details please ask.
Maybe Uruguayan standards?? I'm an expat from the UK so was odd for me.

Thanks again
 

Attachments

Last edited:

marconi

-
Mentor
Arms
Esteemed
Thank you. I am being careful to understand how it is wired now. Eventually I will produce a drawing.
Post automatically merged:

Could you , with great care, study your main consumer unit and establish where the group of three whites above the did connector are supplied from and post a picture. Don,t go sticking your fingers it tools inside to do this. Can you also identify the neutral for the under floor heating and what it connects to. Last take a picture of your main electricity meter(s).
 
Last edited:
  • Thread Starter Thread Starter
  • #14
ok let me try this.

The 3 white cables are wired from an identical adjacent fuse box. These are fed from an identical main breaker (did?). All in the same sequence. Other breakers to supply lights/sockets etc come from the first fuse box.

The main cable coming into the house has these 3 cables feeding into the did/breaker.
Outside we have a breaker at the front gate. The 3 red wires shown are the ones that come into the 1st main fuse box - same sequence again and then into the second box for the floor heating.

Not sure about the neutral.

I can see from the thermostats the cables from the contactors are fed onto the 1st and 2nd screws (must be live and neutral, left live, right neutral). Behind the thermostat you see the orange cables that must be leading to the floor. These do not have a floor thermostat, just air. Looks like the main white connects to the orange and the other orange to the blue. Live and neutral.

4 thermostats here. 2 from one contactor 'kitchen' must be in series, 1 for the living room, and one for the dining room.
Post automatically merged:

Been studying the house for some months now. We moved in last year.
been installing cat6 through the conduits, changing all the wall sockets, adding intelligent lights switches and routers etc.

Found a lot of odd things. Don't even ask me about the main grounding of the house and pool area! All fixed now luckily.
 

Attachments

Last edited:

marconi

-
Mentor
Arms
Esteemed
Any chance of a picture of your meter(s)?
 

marconi

-
Mentor
Arms
Esteemed
It must be getting late where you are. So one last photo please looking up underneath the meters to see the individual wires going into it. Then I will leave you be until tomorrow. I am going to cook some minty lamb mince Devon pasties.


Not 'did' - meant to type disconnector or main breaker if you prefer.

Where are you in Uruguay? I am in London.
 
  • Thread Starter Thread Starter
  • #18
Sounds tasty. Miss many things from the UK.
We're 4 hours behind the UK so on my lunch break now. Work remotely here.
I live in Barra de Carrasco, Canelones. Just outside Montevideo.
Tricky to take photos as the meter is in a big sealed box with a small window just big enough to get my hand in.

Bon Appétit or buen provecho.
Regards
 

Attachments

marconi

-
Mentor
Arms
Esteemed
Good morning. I will start to produce some drawings today. First though please tell me the colours of the wires in the thick supply cable under the meter.

From the meter box it looks like 3 reds head out to your home and no other wires - is this correct? What colours do they connect to at the meter? If you cannot say then please make a drawing for me.

There is also a terminal schematic on the plastic cover over the meter terminals which I cannot see completely - could you draw or photo it and mark up where the wires of the supply and the 3 reds connect to?
 

marconi

-
Mentor
Arms
Esteemed
Observations 1

a. If one studies Drawing 1 attached, one can observe that through the 4 pole disconnector (top left) and then the 3 white wires to above the 5 circuit breakers all the 3 white wires top left are joined together by the black busbar. This means these three white wires top left cannot be L1, L2 and N because a short circuit would have occurred rupturing a fuse or tripping a circuit breaker external to this enclosure. If a short circuit has not happened then they more likely to be of the same potential ie: a line or a neutral. The N, L1, L2 and L3 markings on the disconnector are to inform how it should be connected to such a supply if presented to it.

b. Studying further, one can readily see that each of the 2 wire digital power meters are connected across a 20A circuit breaker - this is incorrect. When the circuit breaker is closed the input to the power meter is short circuited and will not read any power consumption. In addition, the power meter requires an L and N at its input where only an L or N (yet to be confirmed) has actually been connected. I note the meters are reading zero.

c. The output side of the power meter connects to the input of a contactor by the blue and white wires and then from the output of each contactor to the floor heating elements ( I assume at this stage). Because only an L or an N (yet to be confirmed) is provided at the input to each contactor then no supply voltage will ever be connected across the elements - therefore they will not heat up. I suspect then that the underfloor heating system does not work at all at the moment.

d. The timer, albeit now redundant, still has two wires to it presumably intended as its supply - blue and white. Since these are derived wrongly from the two circuit breakers on the far right whose inputs are connected together by the black busbar there will be no voltage supply applied to the timer - it will not function.

e. From d), since the wifi switch has been tapped off the input to the timer it too has not voltage supply and will not function.

f. it would be impossible to measure with respect to earth the three voltages 230, 209 and 23V at the input terminals to the disconnector while it was closed because as mentioned when the disconnector is closed all the two sets of 3 white wires are at the same potential because of the black busbar.

It looks to me then that the wiring for the UFH was wrong from the very start or changes have been made which have resulted in a completely incorrect arrangement. Do you know the history of the UFH - did it ever work?
 

Attachments

  • Thread Starter Thread Starter
  • #21
Observations 1

a. If one studies Drawing 1 attached, one can observe that through the 4 pole disconnector (top left) and then the 3 white wires to above the 5 circuit breakers all the 3 white wires top left are joined together by the black busbar. This means these three white wires top left cannot be L1, L2 and N because a short circuit would have occurred rupturing a fuse or tripping a circuit breaker external to this enclosure. If a short circuit has not happened then they more likely to be of the same potential ie: a line or a neutral. The N, L1, L2 and L3 markings on the disconnector are to inform how it should be connected to such a supply if presented to it.

b. Studying further, one can readily see that each of the 2 wire digital power meters are connected across a 20A circuit breaker - this is incorrect. When the circuit breaker is closed the input to the power meter is short circuited and will not read any power consumption. In addition, the power meter requires an L and N at its input where only an L or N (yet to be confirmed) has actually been connected. I note the meters are reading zero.

c. The output side of the power meter connects to the input of a contactor by the blue and white wires and then from the output of each contactor to the floor heating elements ( I assume at this stage). Because only an L or an N (yet to be confirmed) is provided at the input to each contactor then no supply voltage will ever be connected across the elements - therefore they will not heat up. I suspect then that the underfloor heating system does not work at all at the moment.

d. The timer, albeit now redundant, still has two wires to it presumably intended as its supply - blue and white. Since these are derived wrongly from the two circuit breakers on the far right whose inputs are connected together by the black busbar there will be no voltage supply applied to the timer - it will not function.

e. From d), since the wifi switch has been tapped off the input to the timer it too has not voltage supply and will not function.

f. it would be impossible to measure with respect to earth the three voltages 230, 209 and 23V at the input terminals to the disconnector while it was closed because as mentioned when the disconnector is closed all the two sets of 3 white wires are at the same potential because of the black busbar.

It looks to me then that the wiring for the UFH was wrong from the very start or changes have been made which have resulted in a completely incorrect arrangement. Do you know the history of the UFH - did it ever work?
Wow thanks for your detailed reply.
I'll reply to a few of the points and look into it in more detail later and get back to you.

b - The meters are working perfectly. They measure 230v across the input terminals and 230v across the outputs. They turn over and the green light flashes red when current is flowing through. The dining room was turned on last night and used 2000 kwh. Now reading 5.1 kw

c- the outputs of the meters read 230v (across the white and blue terminals) and feed the contactors. These heat up when the timer activates them. All the floor heating works.

d- the original timer on the right also has 230v across the blue and white wires. This has always worked and did switch on the contactors before I switched the timer over to the sonoff.

f- I measured the 3 voltages with respect to earth at the input of the main breaker (3 white wires).

Every contactor's input terminals has 230v across the white and blue wires and also across the output terminals when switched on (and they get hot).

Sorry to throw a spanner in the works.
I'll have a look at the external meter box later and get back to you.

Many thanks
 

marconi

-
Mentor
Arms
Esteemed
That means then that what I see in the photos is inaccurate. Could you draw the wiring for me to study?

Could you confirm (safely) what the black bar along the 5 cbs is and does? Does it connect together all the top terminals?

Does the group of three whites under the disconnector go to above the 3 left side cbs.
 
  • Thread Starter Thread Starter
  • #23
That means then that what I see in the photos is inaccurate. Could you draw the wiring for me to study?

Could you confirm (safely) what the black bar along the 5 cbs is and does? Does it connect together all the top terminals?

Does the group of three whites under the disconnector go to above the 3 left side cbs.

Your drawing is fine - just the brown and white wires entering the power meters are the other way around. White entering the left terminal and brown entering the right terminal. Everything else matches up.

The black bar along the cbs just appears to join all the cables across which I find odd.
All 3 live power cables?? This will all installed by the authorised national electricity company here, UTE, to their standards.


Yes the group of white wires under the disconnector go above to the 3 cbs in the same sequence also. Left to right.
 

Attachments

marconi

-
Mentor
Arms
Esteemed
Only if you feel safe to do so - would you measure and report the voltages at each of the top three terminals ( 1, 3, 5) of the disconnector to earth and then do the same for the corresponding bottom 3 terminals ( 2 , 4 ,6 )? Ac voltage and a scale to read at least 230V.
 
  • Thread Starter Thread Starter
  • #25
Only if you feel safe to do so - would you measure and report the voltages at each of the top three terminals ( 1, 3, 5) of the disconnector to earth and then do the same for the corresponding bottom 3 terminals ( 2 , 4 ,6 )? Ac voltage and a scale to read at least 230V.
Will do.
Yes I feel safe to do this. I've worked with valve amps, 500v transformers for power outputs and high amperage power supplies for valve heaters etc, and 400+v caps for years. These caps pack a punch even when disconnected. I know what it's like to get a shock and not pleasant (or safe). A charged disconnected cap can cause a lot of pain.
Post automatically merged:

Only if you feel safe to do so - would you measure and report the voltages at each of the top three terminals ( 1, 3, 5) of the disconnector to earth and then do the same for the corresponding bottom 3 terminals ( 2 , 4 ,6 )? Ac voltage and a scale to read at least 230V.

1 (top 1st terminal) - 258
3 (top 2nd terminal) - 28
5 (top 3rd terminal) - 240

2 (bottom 1st terminal) - 214
4 (bottom 2nd terminal) - 26
6 (bottom 3rd terminal) - 238

All measured to ground.
 
Last edited:

marconi

-
Mentor
Arms
Esteemed
Thank you.
If 2, 4 and 6 out of the disconnector were indeed linked together by the black bar above the cbs then the voltage would be the same on each - which is not the case.

So to check further please measure between each of the top terminals of the 5 cbs to earth and then do the same for the bottom terminals to earth.
 
  • Thread Starter Thread Starter
  • #27
Thank you.
If 2, 4 and 6 out of the disconnector were indeed linked together by the black bar above the cbs then the voltage would be the same on each - which is not the case.

So to check further please measure between each of the top terminals of the 5 cbs to earth and then do the same for the bottom terminals to earth.
This may shed some light on the set up and function of the bus now.

Top CBS
1-202
2-24
3-224
4-202
5-24

Bottom CBS
1-202
2-24
3-224
4-202
5-24
 

marconi

-
Mentor
Arms
Esteemed
Yes that I think has resolved much.

At you convenience could you measure at the disconnector the voltage between:

a. 1 and 2, then between 3 and 4 and lastly 5 and 6 ie: across the poles of the disconnector. Why? Because you measured 258V at 1 and 214V at 3 which indicates to me a problem with this pair of contacts - so we will check them all.

b. 1 and 3 to establish you have a 3 phase supply ( 1 to 3 will be 230V ish) or a split phase supply ( 1 to 3 will be 460V ish) - I am pretty sure it is a three phase supply with one line earthed to produce L1, L2 and N (L3 earthed) all phased 120 degrees apart.

The evidence from the voltage readings suggests to me how the panel is wired which I will now draw out.
 
  • Thread Starter Thread Starter
  • #29
ah wait think my scribbles of the voltage of 1 was wrong - let me just check.

my apologies - running up and down in between work tasks
Post automatically merged:

ok that is odd. Not sure why I measured them so differently before. Washing machine is on now. This should have no relevance unless there is an issue somewhere. I'll test again later

Here goes again sorry: (this makes more sense)

1 (top 1st terminal) - 208
3 (top 2nd terminal) - 24
5 (top 3rd terminal) - 230

2 (bottom 1st terminal) - 208
4 (bottom 2nd terminal) - 24
6 (bottom 3rd terminal) - 230

Top CBS
1-208
2-24
3-230
4-208
5-24

Bottom CBS
1-208
2-24
3-230
4-208
5-24
 
Last edited:

marconi

-
Mentor
Arms
Esteemed
The UFH heating is cleverly connected across L1, L2 and N as shown in the diagram below. The black bar above the 5 cbs confused me; the voltage measurements clarified the situation.

Sometime please tell me L1 to L2 voltage. I am pretty sure you have a 3 phase supply arranged as I have drawn.

Otherwise I would swap the contactors for silent ones. Solid state switches can fail short-circuit which would not be a good thing so don't fit them. They also need substantial heatsinks and ventilation around these because they would get too hot without. If it was me I'd buy silent contactors. The three sets of UFH are each protected by a 20A cb. A 32A contactor is beefy enough to carry up to 20A 'all day long' and be more reliable than one rated close to 20A. Space the power meters and contactors apart so that there is some air movement and one does not warm the other.

Thank you for your patience!

:)

Marconi
 

Attachments

  • Thread Starter Thread Starter
  • #31
The UFH heating is cleverly connected across L1, L2 and N as shown in the diagram below. The black bar above the 5 cbs confused me; the voltage measurements clarified the situation.

Sometime please tell me L1 to L2 voltage. I am pretty sure you have a 3 phase supply arranged as I have drawn.

Otherwise I would swap the contactors for silent ones. Solid state switches can fail short-circuit which would not be a good thing so don't fit them. They also need substantial heatsinks and ventilation around these because they would get too hot without. If it was me I'd buy silent contactors. The three sets of UFH are each protected by a 20A cb. A 32A contactor is beefy enough to carry up to 20A 'all day long' and be more reliable than one rated close to 20A. Space the power meters and contactors apart so that there is some air movement and one does not warm the other.

Thank you for your patience!

:)

Marconi
I'll get back to you soon - just had an incident where my wife's car battery died completely when she needed to go out most- looks like a dead cell. 3v when disconnected!!

Not a happy wife at the moment. (apparently my fault for buying a GM car)
 

marconi

-
Mentor
Arms
Esteemed
My last missive for today - Lucien Nunes is the chap if you want to discuss valve amplifiers.

Corrigendum: the disconnector also includes a 40A cb in each pole which I did not make clear - before my colleagues correct me ;-)
 
  • Thread Starter Thread Starter
  • #33
Any chance of a picture of your meter(s)?
Sorry haven't got around to that yet. Home schooling after work till 10pm then bed due to early zoom meetings.

Just now I measured the voltages across the terminals of the main disconnector breaker.
225/226v across each one. 1-2, 1-3, 2-3.

So we have a 3 phase supply by the looks of it.

Now what kind of new contactor would I need for the 3 zones and how to wire this up properly?

Many thanks
 

marconi

-
Mentor
Arms
Esteemed
It is not easy for me to research the brands available in Uruguay. What I suggest you do is google or go to an electrical supplier and look for:

1. Silent contactor - the ac mains applied to A1 and A2 is rectified inside the contactor and then used to energise the coil.
2. Double Pole
3. At least 32A ac resistive load rating ie: low inductance like the UFH load.
4. 220-240V ac supply for coil (but see 1 above).
5. DIN rail fitting.
6. Study the number of switching operations figure - to handle a large number of open/close contact actions at rated current is a sign of 'goodness' so a high value to be preferred to a contactor with a low/lower figure.

Once you have found some options I will check them before you purchase should you wish.

The digital power meters are wired before the contactor as now. You will though ditch the doubled up 2mm2 for a single suitable 4mm2 wire.

With regards to wiring them in to the control logic - are you using your phone/wifi and SONOS switch to replace the timeswitch? And this then provides the live feed to the zone thermostats? The switched live from the zone thermostats then provides the A1 input to the corresponding zone contactor with a Neutral being provided to the A2.

Or are you going to have wifi thermostats too some of which incorporate a time/day programmer?

Or are you going to go the whole hog and introduce smart home technology to control the UFH? If so you would be better off starting a new thread and exploring options with EF colleagues who install this for a living. Once you have contactors you can apply a switched live to them via wifi switches which you can interface with smart home technology. My neighbour has British Gas HIVE but there are other suppliers.

Regards

Marconi
 
  • Thread Starter Thread Starter
  • #35
It is not easy for me to research the brands available in Uruguay. What I suggest you do is google or go to an electrical supplier and look for:

1. Silent contactor - the ac mains applied to A1 and A2 is rectified inside the contactor and then used to energise the coil.
2. Double Pole
3. At least 32A ac resistive load rating ie: low inductance like the UFH load.
4. 220-240V ac supply for coil (but see 1 above).
5. DIN rail fitting.
6. Study the number of switching operations figure - to handle a large number of open/close contact actions at rated current is a sign of 'goodness' so a high value to be preferred to a contactor with a low/lower figure.

Once you have found some options I will check them before you purchase should you wish.

The digital power meters are wired before the contactor as now. You will though ditch the doubled up 2mm2 for a single suitable 4mm2 wire.

With regards to wiring them in to the control logic - are you using your phone/wifi and SONOS switch to replace the timeswitch? And this then provides the live feed to the zone thermostats? The switched live from the zone thermostats then provides the A1 input to the corresponding zone contactor with a Neutral being provided to the A2.

Or are you going to have wifi thermostats too some of which incorporate a time/day programmer?

Or are you going to go the whole hog and introduce smart home technology to control the UFH? If so you would be better off starting a new thread and exploring options with EF colleagues who install this for a living. Once you have contactors you can apply a switched live to them via wifi switches which you can interface with smart home technology. My neighbour has British Gas HIVE but there are other suppliers.

Regards

Marconi
Hi Marconi.


No not easy for any of us to research items here. Nothing like screwfix etc.

Can I use one 40A contactor to replace all 3? Using the 3 poles of a 4 pole contactor?

This year currently got one sonoff temperature probe (TH10) in the living which will have a schedule and temperature range (from the app/amazon/IFTTT) and in turn activate the other sonoff R3 inside the fusebox to energize A1/A2. I imagine 95% of the time it will be switched on for the few hours it will be on a day.

Maybe in the future if we continue using the floor heating I'll look at more advanced systems to control each zone.

Many thanks
 

marconi

-
Mentor
Arms
Esteemed
Nearly on the outside of a bottle of wine now so to be safe I will answer tomorrow morning.

Until then it'd be useful to know what you want to achieve in terms of functionality for each zone now.
 
  • Thread Starter Thread Starter
  • #37
Nearly on the outside of a bottle of wine now so to be safe I will answer tomorrow morning.

Until then it'd be useful to know what you want to achieve in terms of functionality for each zone now.
almost 6pm in the UK so ok for me to crack open a bottle now? Probably not yet as I'm preparing SQL scripts for a major live deployment on Monday! (Database developer)

Salud!
Post automatically merged:


Post automatically merged:

We're also going to evaluate the cost of running the UFH this winter. We had plans to install another heating system (plus double glazing) but the global crisis put a stop to that.

I love the UFH but been calculating the costs and will be about 1 GBP per hour. That soon adds up. 9-10 kwh for both floors. We'll be testing a different number of zones to see how much we need on to heat the house sufficiently.
 
Last edited:

marconi

-
Mentor
Arms
Esteemed
How much is a kWh day and night? We buy our gas and leccie from EDF (Electricite de France) and have Economy 7 so cheap 7 hours overnight 0000-0700 GMT at:

Electricity day unit rate: 15.67p per kWh
Electricity night unit rate: 9.73p per kWh
Daily standing charge: 23.86p per day

Gas unit rate: 2.870p per kWh
Daily standing charge: 20.48p per day
 
  • Thread Starter Thread Starter
  • #39
How much is a kWh day and night? We buy our gas and leccie from EDF (Electricite de France) and have Economy 7 so cheap 7 hours overnight 0000-0700 GMT at:

Electricity day unit rate: 15.67p per kWh
Electricity night unit rate: 9.73p per kWh
Daily standing charge: 23.86p per day

Gas unit rate: 2.870p per kWh
Daily standing charge: 20.48p per day
We have the double tariff plan. (single, double and triple available) If you have triple 00:00-07:00 is even cheaper but then 7am-5pm is a bit more expensive. We have a pool with pump/filter running 7-8 hours until 5pm so the triple tariff is not worth it for us.

Also just had a 10% increase in prices this year. Normal developing world inflation!!


11pm - 5pm: 4.6 pesos kWh (8.64 pence)
5pm - 11pm: 11.59 pesos kWh (21.77 pence)
monthly fixed charges: £35 more or less


Our fixed charges are quite high as we have 15kW available. You can have a smaller kW available with less fixed charges but obviously that won't work with UFH. Also we have A/C for the summer. Years ago in a small flat we had A/C and kept tripping the main breaker due to the small kW available.

Dinner time gets expensive with the oven and hob at 22 pence per kWh! Unless you are very organized and cook before 5pm!

I was with ovo in Lichfield, UK. Was impressed with them and worked out fairly cheap on the dual tariff.
Post automatically merged:


Post automatically merged:

Btw this is the contactor used for the 1st floor. 3 bedrooms, landing and 2 bathrooms. All through this one 4 pole. Split into 2 zones (2 cbs). Super silent 40a.
 

Attachments

Last edited:
  • Thread Starter Thread Starter
  • #40
I was thinking. Upstairs the small zones don't pull much current.
There is a contactor for 4 zones.
The small landing for example only pulls about 800-1000w?
Surely I can safely wire this directly from the 16amp CBS to a wifi switch of 10-16amps instead of the contactor?
 

marconi

-
Mentor
Arms
Esteemed
ABB ESB40-40-230AC/DC - https://new.abb.com/products/GHE3491102R0006/esb40-40-230ac-dc-installation-contactor

The ABB contactor is a good make and well suited. It is a silent or hum-free design and the 40A AC1 (resistive and low inductance or PF nearly 1) rating for the contacts is excellent for your application.

I don't know what the Uruguay electrical regulations stipulate for switching to countenance single pole switching. At the moment all your contactors are used for double pole switching; this is certainly necessary for those UFH elements wired across L1 and L2 but for those across L1-N and L2-N single pole may be allowed - I just don't know. However, double pole is to be preferred because it maintains uniformity of wiring scheme for the UFH system and there is some advantage in splitting the arc across two pairs of contacts when they open to prolong life. I would not opt for single pole switching.

The aforesaid means that to continue with double pole switching you would need to obtain a 6 pole contactor if you wanted one to switch three sets of heating elements in the way a showed in my last diagram. Such a contactor I is rarer than 4 pole and thus I expect pricier. I don't know if you can obtain a silent 6 pole contactor.

Using one contactor to switch 2 or more UFH zones has two drawbacks; if it fails you have lost all heating and when it closes or opens the large current change will cause a noticeable and perhaps troublesome voltage transient in your home and maybe to your neighbours. Far better to sub-divide the load switching over 3 contactors to reduce the magnitude of each transient step. Already I notice that you have quite a variation in supply voltage as loads in your home are powered on and off which indicates a higher supply impedance than is typical in the UK. Switching the UFH zones as one will be noticeable and annoying.

Which leads on to the idea of switching each zone directly using a wifi 'contactor'. In theory this is possible but great care is needed to ensure the power contacts have an adequate AC1 rating and can cope with frequent switching during the day. I'd have to see the specification to comment further. Would it be silent? Would I do it in 'one step'? - no, because I like my functionality appropriately realised in the best possible way. I speak from an industrial background so in the domestic setting one might be more inclined to economy of components.

Sorry about the rather long-winded reply - I have nothing else to do.

:)
 
  • Thread Starter Thread Starter
  • #42
ABB ESB40-40-230AC/DC - https://new.abb.com/products/GHE3491102R0006/esb40-40-230ac-dc-installation-contactor

The ABB contactor is a good make and well suited. It is a silent or hum-free design and the 40A AC1 (resistive and low inductance or PF nearly 1) rating for the contacts is excellent for your application.

I don't know what the Uruguay electrical regulations stipulate for switching to countenance single pole switching. At the moment all your contactors are used for double pole switching; this is certainly necessary for those UFH elements wired across L1 and L2 but for those across L1-N and L2-N single pole may be allowed - I just don't know. However, double pole is to be preferred because it maintains uniformity of wiring scheme for the UFH system and there is some advantage in splitting the arc across two pairs of contacts when they open to prolong life. I would not opt for single pole switching.

The aforesaid means that to continue with double pole switching you would need to obtain a 6 pole contactor if you wanted one to switch three sets of heating elements in the way a showed in my last diagram. Such a contactor I is rarer than 4 pole and thus I expect pricier. I don't know if you can obtain a silent 6 pole contactor.

Using one contactor to switch 2 or more UFH zones has two drawbacks; if it fails you have lost all heating and when it closes or opens the large current change will cause a noticeable and perhaps troublesome voltage transient in your home and maybe to your neighbours. Far better to sub-divide the load switching over 3 contactors to reduce the magnitude of each transient step. Already I notice that you have quite a variation in supply voltage as loads in your home are powered on and off which indicates a higher supply impedance than is typical in the UK. Switching the UFH zones as one will be noticeable and annoying.

Which leads on to the idea of switching each zone directly using a wifi 'contactor'. In theory this is possible but great care is needed to ensure the power contacts have an adequate AC1 rating and can cope with frequent switching during the day. I'd have to see the specification to comment further. Would it be silent? Would I do it in 'one step'? - no, because I like my functionality appropriately realised in the best possible way. I speak from an industrial background so in the domestic setting one might be more inclined to economy of components.

Sorry about the rather long-winded reply - I have nothing else to do.

:)
Many thanks for the full write up.
I'll look for 3 abb contactors following your advice.
Now the upstairs box is a right mess and I want to tidy it up.
Looks like we have 1 contactor for 4 zones. 4 live cables going out but one neutral for each 2 live cables. Live cables on terminals 2 and 3(2 coming out of each). I'll need to draw this out as looking at the mess it's impossible to see. I traced which wires go to which ufh last night as I want to control my office ufh independently.
 

Attachments

marconi

-
Mentor
Arms
Esteemed
As you are the father, spouse and breadwinner please take heed of this: If you are going to be putting your fingers in among the wiring you must invest in an approved voltage indicator in order to prove dead once you have de-energised and isolated. A digital voltmeter or a neon screwdriver are not reliable. You do not need to spend much. I have a DILOG because they are good value for money and I rarely do any work these days preferring to employ an electrician for anything major.

ISOPK2 | Di-LOG - https://www.dilog.co.uk/product/isopk2/

Time spent discovering how things have been wired is well spent - do not assume anything.
 
Last edited:
  • Thread Starter Thread Starter
  • #44
As you are the father, spouse and breadwinner please take heed of this: If you are going to be putting your fingers in among the wiring you must invest in an approved voltage indicator in order to prove dead once you have de-energised and isolated. A digital voltmeter or a neon screwdriver are not reliable. You do not need to spend much. I have a DILOG because they are good value for money and I rarely do any work these days preferring to employ an electrician for anything major.

ISOPK2 | Di-LOG - https://www.dilog.co.uk/product/isopk2/

Time spent discovering how things have been wired is well spent - do not assume anything.
Thanks for the link of suggested equipment Marconi. Sound advice.

I've done a sketch of how I believe 2 of the rooms are wired up upstairs. From one of the 4 pole outlets they have 2 live wires going to each room. Just one blue neutral though on series. I would like to have these 2 controlled rooms controlled independently. Not sure how that would be achieved without installing a new digital thermostat on the wall. Would like to have them cabled independently like I do downstairs with the double pole contactors or something similar. They only draw about 1000w each.
 

Attachments

  • Thread Starter Thread Starter
  • #45
I'm thinking I'd probably need to feed an individual neutral cable to one of the rooms so they are separate circuits.

I'll wait for advice.

Thanks
 

marconi

-
Mentor
Arms
Esteemed
Good morning. Re #44. Could you measure the voltage between earth and the red and then the blue on the supply side of the contactor to establish their potential please. I suspect they are connected to L1 and L2.
 
  • Thread Starter Thread Starter
  • #47
Good morning. Re #44. Could you measure the voltage between earth and the red and then the blue on the supply side of the contactor to establish their potential please. I suspect they are connected to L1 and L2.
Good morning

Red reads 23v
Blue 226v

So poles 1-4:
207
23
23
226

Many thanks
 

marconi

-
Mentor
Arms
Esteemed
Did you spot the danger in the wiring shown in your picture in #42? You will have to sleeve the red conductor or shorten it. Until then keep your fingers out!

The zone you mention is fed across L-N and I am pretty sure L2-N because your L2 is higher voltage than your L1 in previous readings.

You will need two double pole contactors each supplied by the same L-N pair as now.

Each of the elements is then fed by a double pole output from one or the other contactor.

Alas, you will have to run in a new neutral to the point where the elements' Ns are joined - but you expected the requirement to do that. It was lazy wiring not to run one in the first place. Use the same thickness cable as now.

You can then think about one of these wireless thermostats and receivers for each element such as these:

Honeywell RF DT92E1000 Wireless Digital Room Thermostat | ElectricalDirect - https://www.electricaldirect.co.uk/product/honeywell-rf-dt92e1000-wireless-digital-room-thermostat-611235?vat=1&shopping=true&gclid=Cj0KCQjwhZr1BRCLARIsALjRVQP_fehCHwVa2GQkvKOaTv03u74WSe2iyqTlWLn4Ehsbqn3kHMTNCMcaAqTsEALw_wcB

Or a programmable wireless thermostat like this one:

2 in 1 Programmable Wireless Room Thermostat - 22874 - Controls | BES.co.uk - https://www.bes.co.uk/2-in-1-programmable-wireless-room-thermostat-22874
 
  • Thread Starter Thread Starter
  • #49
Did you spot the danger in the wiring shown in your picture in #42? You will have to sleeve the red conductor or shorten it. Until then keep your fingers out!

The zone you mention is fed across L-N and I am pretty sure L2-N because your L2 is higher voltage than your L1 in previous readings.

You will need two double pole contactors each supplied by the same L-N pair as now.

Each of the elements is then fed by a double pole output from one or the other contactor.

Alas, you will have to run in a new neutral to the point where the elements' Ns are joined - but you expected the requirement to do that. It was lazy wiring not to run one in the first place. Use the same thickness cable as now.

You can then think about one of these wireless thermostats and receivers for each element such as these:

Honeywell RF DT92E1000 Wireless Digital Room Thermostat | ElectricalDirect - https://www.electricaldirect.co.uk/product/honeywell-rf-dt92e1000-wireless-digital-room-thermostat-611235?vat=1&shopping=true&gclid=Cj0KCQjwhZr1BRCLARIsALjRVQP_fehCHwVa2GQkvKOaTv03u74WSe2iyqTlWLn4Ehsbqn3kHMTNCMcaAqTsEALw_wcB

Or a programmable wireless thermostat like this one:

2 in 1 Programmable Wireless Room Thermostat - 22874 - Controls | BES.co.uk - https://www.bes.co.uk/2-in-1-programmable-wireless-room-thermostat-22874
Thanks Marconi. If you feel the urge a diagram would be very helpful thanks.

Yes looks like the 2 other zones have the same set up. (using the 1st and 2nd poles each going to 2 zones). 6 zones in total from the 3 poles.

btw that black tape on the red cable is just holding the 3 wires in a bundle don't worry no connections under the insulating tape. Looks like they ran out of cable ties!! A lot of laziness in this set up.
 
  • Thread Starter Thread Starter
  • #51
Could you please send me a photo(s) which shows the current upstairs control wiring?
hmm odd the fpg images are not uploading tonight. I'll try again later
"The uploaded file was not an image as expected."
 
  • Thread Starter Thread Starter
  • #54
Hi Marconi,

Hope this works as I've been unable to upload any more photos which is odd. Maybe a limitation on my account? Used an image sharing site for these.
Think I will need to draw a diagram as its such a mess in here. Put some tape around a couple of cables just to label them




 
  • Thread Starter Thread Starter
  • #55
I'll get a drawing to you later once I have a moment to remove the plastic panel cover to check again. In the meantime I've set up a nice automation server on a docker. Some scripting with the sensors and works brilliantly. So many options here.

 
  • Thread Starter Thread Starter
  • #56
Hi Marconi.

I believe this is how they have wired it. 2 of the UFH zones are tiny (1m2) bathrooms so use very little. Not 100% on the middle UFH but looks like they share the same cables.

 

marconi

-
Mentor
Arms
Esteemed
Hello. What I cannot gauge from the photos is how much space is available on the DIN rail to clip on new double pole contactors. The space available for the new ones determines how many separately controlled zones can be configured. Could you have a gander and tell me please?
 
  • Thread Starter Thread Starter
  • #58
If I remove the old timer on the left and move the cbs to the left I have about 22/23 cm to play with. Would like to have the one power meter in there (about 1cm wide) measuring all the kWh used by all the combined UFH zones. Good up to 40amps.

I'd be happy if I could just separate the last 2 UFH zones on the right.

Many thanks
 

marconi

-
Mentor
Arms
Esteemed
A standard DIN module is 17.5mm wide. So with two power meters that is 35mm - one for L1 and one for L2. Which leaves 220-35 = 185mm

A double pole 20A ABB contactor is a standard DIN module -the spec says 18mm. So you could fit in up to 10 of them.

ABB ESB20-20N-01 - https://new.abb.com/products/1SBE121111R0120/esb20-20n-01-installation-contactor

Could you have a think about how you want the zones arranged knowing that you have room for circa 12 standard DIN modules - and do you want a power meter for each zone?
 
  • Thread Starter Thread Starter
  • #61
A standard DIN module is 17.5mm wide. So with two power meters that is 35mm - one for L1 and one for L2. Which leaves 220-35 = 185mm

A double pole 20A ABB contactor is a standard DIN module -the spec says 18mm. So you could fit in up to 10 of them.

ABB ESB20-20N-01 - https://new.abb.com/products/1SBE121111R0120/esb20-20n-01-installation-contactor

Could you have a think about how you want the zones arranged knowing that you have room for circa 12 standard DIN modules - and do you want a power meter for each zone?
Hi Marconi,

I will visit my local home department store to see what they have available in terms of contactors first. We don't always have a wide selection of products and can be pricey.

I should be able to fit a new neutral cable into one or 2 of the rooms as you mentioned earlier to separate the 2 bedrooms but the rooms further away could be problematic if I need to fit more cables. I've had issues trying to get my fishline down some of the conduits. Quite a spaghetti junction! Took me 2 days to get the cat6 from my office down to the living room!

I'll get back to you.
Thanks very much for all your time on this.
 
  • Thread Starter Thread Starter
  • #62
Sorry been absent for a while. Worries with work and the pandemic etc.
Been difficult to find suitable contactors at a reasonable price. Found some 4 pole contactors. Shouldn't be any issue swapping 2 x 2 pole contactors for 1 x 4 pole should it? 2 live and 2 neutral inputs and outputs. Each 2 pole is only drawing about 10 amps. The 4 pole is a a 40amp.

Thanks
 

marconi

-
Mentor
Arms
Esteemed
The 4 pole sounds fine. If you send me its details I will give it the once over.

:)
 
  • Thread Starter Thread Starter
  • #64
The 4 pole sounds fine. If you send me its details I will give it the once over.

:)
I believe it is the same one as this:


Many thanks

Was going to leave it for this year but the buzzing from the downstairs is really quite annoying now as we have the heating on more frequently as winter is approaching here in the Southern Hemisphere.
 
  • Thread Starter Thread Starter
  • #66
I cannot read the make - what is it?
Can't find much info on it but the listing says 'Carfil'. CF2804
 

marconi

-
Mentor
Arms
Esteemed
At first blush they look rather cheap and cheerful. Here is a proposal: I will send you some ABB silent relays and perhaps you will make a donation to a children's charity in Uruguay akin to the UK's NSPCC - what say you?
 
  • Thread Starter Thread Starter
  • #68
At first blush they look rather cheap and cheerful. Here is a proposal: I will send you some ABB silent relays and perhaps you will make a donation to a children's charity in Uruguay akin to the UK's NSPCC - what say you?
Wow really appreciate the offer. Very kind of you indeed.

Unfortunately, the customs rules here are very strict and could end up paying a fortune in taxes and import duty fees requiring proof of purchase etc. List goes on of extra costs on top of the 60% tax.
This is why even cheap chinese goods are expensive here.

I'll probably just go for this model and try one first.

Kind regards
 

marconi

-
Mentor
Arms
Esteemed
I understand. I will do some research tomorrow morning over a coffee. At 10 A and rated at 40 A they are most likely suitable - but I thought you wanted quiet contactors(*)

I, and maybe many others, have a bit of a downer on Chinese products at the moment if that is where this contactor is from. I find Italian made stuff good value - but then I have Italian ancestry with the surname 'Solari' - so I may be biased ;-)

* - We could try to be clever and put good but noisy contactors inside soundproofed enclosures? I'll have a look at materials and ways to attenuate the annoying hum. At first pass I wonder about some lead and rubber combination.
 
Last edited:
  • Thread Starter Thread Starter
  • #70
Yes I would prefer fairly quiet contactors. Not sure how much noise these would make tbh.

One out of the 3 downstairs is really buzzing loudly (the buzzing varies from day to day, from quite loud to a sound like its vibrating out of the module box), obviously not very well.

As you know the one upstairs is a 4 pole ABB and you cannot hear it at all. Super silent.

I have asked the supplier how much noise they produce.
Update: He's just replied and said they are not quiet.
Post automatically merged:

oh look in this moment new models have appeared online.

Steck



 
Last edited:
  • Thread Starter Thread Starter
  • #71
Last edited:

marconi

-
Mentor
Arms
Esteemed
Remember to switch off all the electricity and check everything is dead before you work on the swap. Label up the wiring too so the pairs are identifiable and recorded somehow near the contactor. Last, all connections must be tight and use all the strands of the conductors without any of them showing outside the entry to the terminal channel. Then it will nearly be as good a job as done by DPG ( :) ) - but only nearly so don't get carried away. Let us know how you get on - pictures are always good if you want your work checked and assessed.
 
  • Thread Starter Thread Starter
  • #73
Remember to switch off all the electricity and check everything is dead before you work on the swap. Label up the wiring too so the pairs are identifiable and recorded somehow near the contactor. Last, all connections must be tight and use all the strands of the conductors without any of them showing outside the entry to the terminal channel. Then it will nearly be as good a job as done by DPG ( :) ) - but only nearly so don't get carried away. Let us know how you get on - pictures are always good if you want your work checked and assessed.
Thanks will do.

Just purchased 3 of them. Got some 4mm wiring also to replace the 2 x 2mm wiring.
One of the 3 old ones was vibrating so much this morning I had to turn it off as my son was having a zoom school class and was interfering with his class! (home schooling still continuing here in Uruguay)
 
  • Thread Starter Thread Starter
  • #75
The UFH heating is cleverly connected across L1, L2 and N as shown in the diagram below. The black bar above the 5 cbs confused me; the voltage measurements clarified the situation.

Sometime please tell me L1 to L2 voltage. I am pretty sure you have a 3 phase supply arranged as I have drawn.

Otherwise I would swap the contactors for silent ones. Solid state switches can fail short-circuit which would not be a good thing so don't fit them. They also need substantial heatsinks and ventilation around these because they would get too hot without. If it was me I'd buy silent contactors. The three sets of UFH are each protected by a 20A cb. A 32A contactor is beefy enough to carry up to 20A 'all day long' and be more reliable than one rated close to 20A. Space the power meters and contactors apart so that there is some air movement and one does not warm the other.

Thank you for your patience!

:)

Marconi

Hi Marconi,

Hope you are well.

Just revisiting this topic. Everything is running fine but had a doubt about the type of phase we have. The utility company changed our meter this week with a new smart meter after we had an issue with our bills after using the UFH (the clock was 4 hours out on the old meter so the cheap rates before 5pm were being calculated incorrectly!!)

From what I understood the 3 phase power set ups have 4 cables entering but single phase have only 3 (L1, L2, N).

You mentioned it was a 3 phase initially. Was it decided that this was a single phase in the end with L1, L2 and N?

Many thanks
 

marconi

-
Mentor
Arms
Esteemed
threephase 2wirecornergrounded delta.png

Your supply is 'three phase 2 wire corner grounded delta' as in the diagram above but your line voltage is 225V (ish) instead of the 480V this diagram shows.

So in your home A is L1 and C is L2 and B is the earthed phase/line/neutral N.

Single phase supplies are derived by connecting between pairs of lines A-B, A-C and B-C.

Your UFH uses all these pairings to 'spread' the loading over the three lines/phases since this is a large long duration power demand and makes best use of capacity of the three lines to your home.

I did not delve into how all your other home final circuits are wired eg: lighting and sockets but I strongly suspect they are connected A-B thus L1-N, and B-C thus L2-N so that single pole switching may be used in the line/phase only because only L1 and L2 are at 225V wrt to N and E.... and N is at a low voltage wrt to E - I think we measured 20V ish.

When L1 and L2 are used the switching must be double pole as you have gathered from the contactor contacts wiring for the UFH because both lines are at 225V wrt to N and E.
 
  • Thread Starter Thread Starter
  • #77
Hi Marconi.

I believe this is how they have wired it. 2 of the UFH zones are tiny (1m2) bathrooms so use very little. Not 100% on the middle UFH but looks like they share the same cables.


Hi again,

Revisiting this set up from upstairs. I haven't added individual contactors yet with new neutral cables splitting them up.

My question/doubt now is about the power meter I have installed.

I have the 2 inputs of the power meter fed from the CBS outputs #4 and #5. I thought this would measure only 4 of the zones.

The red led on the power meter pulses depending on the power going through it. Remains green when no power is going through it.

Now what I observed is that it measures power from all 6 zones here. The led flashes at different rates for each zone UFH tested independently.

Is this due to the way the three phase 2 wire corner grounded delta works, and is capable of measuring the power used correctly for all zones?

Thanks in advance
 

marconi

-
Mentor
Arms
Esteemed
In order to measure the power consumed by each of the three UFH zones the power meters P need to wired in between the zones and the contactor C as I have drawn in my attached diagram.

The same holds for elsewhere in your home to monitor power consumption by each UFH zone. So you should revisit how the power meters have been wired in - I cannot do that for you because I can no longer open any attached images in previous posts.

The total power consumption of your home however is measured by two meters - you might have thought three were required. For a three phase three wire system only two meters are necessary; the total power consumption being the sum of the two readings. Blondel's theorem if you want to look it up. My second attachment shows how they are connected. Note how the two meters are both connected to the third line N/L3.

If there were three meters they would be connected as in the last drawing, one in each line and the meters then connected to a common star node. Simply by making one of the lines common to the power meters one of the three meters becomes superfluous and an economy can be made.

Blondel's theorem:

Blondel’s theorem | Power in Poly-Phase System | Electricalvoice - https://electricalvoice.com/blondels-theorem-power-in-poly-phase-system/
 

Attachments

  • Thread Starter Thread Starter
  • #79
In order to measure the power consumed by each of the three UFH zones the power meters P need to wired in between the zones and the contactor C as I have drawn in my attached diagram.

The same holds for elsewhere in your home to monitor power consumption by each UFH zone. So you should revisit how the power meters have been wired in - I cannot do that for you because I can no longer open any attached images in previous posts.

The total power consumption of your home however is measured by two meters - you might have thought three were required. For a three phase three wire system only two meters are necessary; the total power consumption being the sum of the two readings. Blondel's theorem if you want to look it up. My second attachment shows how they are connected. Note how the two meters are both connected to the third line N/L3.

If there were three meters they would be connected as in the last drawing, one in each line and the meters then connected to a common star node. Simply by making one of the lines common to the power meters one of the three meters becomes superfluous and an economy can be made.

Blondel's theorem:

Blondel’s theorem | Power in Poly-Phase System | Electricalvoice - https://electricalvoice.com/blondels-theorem-power-in-poly-phase-system/
Many thanks Marconi.

I do have one doubt - the current set up I have to read the power seems to register power going through UFH 1 and 2 as labelled also which surprised me. I thought it would have only read power on the other lines to the UFH. In fact, it registers power for each UFH if turned on individually.

Is it giving me false readings set up this way?

Appears to read about 1.1 Kwh for the large UFH 1 and 0.2 Kwh for 2 (small bathroom 1.5m2) which I expected but as mentioned I would not have expected it to read any power for these 2 the way it is connected.
Rather confused.

Regards
Post automatically merged:

Just going to double check my drawing later - see if I have identified the connections from and to the PM correctly.
 

Attachments

Last edited:
  • Thread Starter Thread Starter
  • #80
If I do need the 2 power meters to measure accurately the 3 phase upstairs following the 3rd setup would this be the correct way to wire them up?

Still curious why my current one PM set up connected to just the L2 and N/L3 is measuring power for all 6 UFH zones.

Thanks
 

Attachments

marconi

-
Mentor
Arms
Esteemed
If you want to measure total power provided by the 3 phase 3 wire supply to all the UFH connected to a panel then use two meters as I showed in my second diagram ie: place the two meters between the main switch and the contactors. The input to one meter is L1-N and to the other L2-N.

If you want to measure the power consumed by an individual UFH zone (effectively a single phase circuit) then use my first diagram ie: place the PM between the output of the contactor and the UFH zone. The input will be one of these pairs L1-N, L2-N or L1-L2.

Be careful to use the correct terminals on the PM ie: Lin, Lout, Nin and Nout (though it is most likely Nin and Nout are the same node so it is immaterial which is in and which is out.

I cannot turn up the spec for the DM25S - do you have it?

If you wish we can arrange a zoom session if that would be easier for you.

Regards

Marconi
 
  • Thread Starter Thread Starter
  • #82
Sorry just posted and saw your post above as I'm reading through it now.

Perfect many thanks again.

I'll go for set up #2. 2 power meters between the CBS and contactor. Just need the total for all.
So my figures for the UFH#1/#2 are incorrect as I do not have L2 connected even though the PM shows some power feeding through it, possibly just a % of the total power. Did suspect the street side new meter was reading more KwH than I calculated when running the UFH upstairs. Downstairs is pretty much spot on.

Will purchase another PM.
Post automatically merged:

I have found these specs (mine is the 40 amp version).

Model Number:
DM25S
Display Type:
Digital Only
Phase:
Single Phase
Measuring Energy Range:
0-99999
Accuracy Class:
Class1
Output Voltage:
220VAC,110VAC
Operating Temperature:
-25℃~+55℃
Dimensions:
DIN EN50022 Standard
Product Name:
Meter Energy
Width:
18mm (One Module)
Current Specification (A):
5(20),5(30)A,5(40)A
Frequency:
50-60HZ
Constant:
2000imp/kWh
Display Mode:
5+1 Digits Counter Display
Connection Mode:
Direct Mode
Standard:
IEC60253-21
 
Last edited:
  • Thread Starter Thread Starter
  • #83
Sorry just posted and saw your post above as I'm reading through it now.

Perfect many thanks again.

I'll go for set up #2. 2 power meters between the CBS and contactor. Just need the total for all.
So my figures for the UFH#1/#2 are incorrect as I do not have L2 connected even though the PM shows some power feeding through it, possibly just a % of the total power. Did suspect the street side new meter was reading more KwH than I calculated when running the UFH upstairs. Downstairs is pretty much spot on.

Will purchase another PM.
Post automatically merged:

I have found these specs (mine is the 40 amp version).

Model Number:
DM25S
Display Type:
Digital Only
Phase:
Single Phase
Measuring Energy Range:
0-99999
Accuracy Class:
Class1
Output Voltage:
220VAC,110VAC
Operating Temperature:
-25℃~+55℃
Dimensions:
DIN EN50022 Standard
Product Name:
Meter Energy
Width:
18mm (One Module)
Current Specification (A):
5(20),5(30)A,5(40)A
Frequency:
50-60HZ
Constant:
2000imp/kWh
Display Mode:
5+1 Digits Counter Display
Connection Mode:
Direct Mode
Standard:
IEC60253-21
My previous drawing of the power meter was incorrect. The middle output of the CBS is the N feeding to the middle 2 inputs of the contactor.
I have swapped the power meter over to the other live and neutral to measure ufh 1 and 2 for now.
 
  • Thread Starter Thread Starter
  • #84
I suspected measuring the UFH #1 and #2 with the PM wired connected to L1 and N (as opposed to L2 and N) the Kwh is double than previously measured.
 
  • Thread Starter Thread Starter
  • #85
Left hand drawing is the proposed wiring for the 2 x PM's. With the N line going in and out of both power meters. is this correct according to your diagram? Right is original wiring.

Thanks
 

Attachments

marconi

-
Mentor
Arms
Esteemed
Yours will work but it is simpler to do it like my attached diagram. Add the wire I have indicated in blue to go to the link between the middle terminals of the CTR and remove the two I have indicated in white.

(A power meter needs to know the voltage which it obtains from the two inputs and the current flow between the line input and line output. This why we can dispense with the white wires.)
 

Attachments

  • Thread Starter Thread Starter
  • #87
Yours will work but it is simpler to do it like my attached diagram. Add the wire I have indicated in blue to go to the link between the middle terminals of the CTR and remove the two I have indicated in white.

(A power meter needs to know the voltage which it obtains from the two inputs and the current flow between the line input and line output. This why we can dispense with the white wires.)
Many thanks Marconi.

I think I will do the same with the downstairs wiring. 2 x powermeters between the main CBS and contactors (currently have 3 after the 3 contactors). I really only need to measure the total going through the 3 phase wiring now. This way I can re-use one of the 3 PM's I have and install it upstairs. So I'll have 2 downstairs and 2 upstairs. Makes the wiring a bit neater also.

Have a good weekend
 
  • Thread Starter Thread Starter
  • #88
Many thanks Marconi.

I think I will do the same with the downstairs wiring. 2 x powermeters between the main CBS and contactors (currently have 3 after the 3 contactors). I really only need to measure the total going through the 3 phase wiring now. This way I can re-use one of the 3 PM's I have and install it upstairs. So I'll have 2 downstairs and 2 upstairs. Makes the wiring a bit neater also.

Have a good weekend
All completed this weekend. 2 power meters installed between the CBS and contactors downstairs and 2 upstairs. Working Perfectly.

Thank you very much Marconi!
 

Reply to Changing original 32Amp contactors for solid state relays? in the Electric Underfloor Heating Wiring area at ElectriciansForums.net

Instyle LED Lighting Specialists UK
This official sponsor may provide discounts for members
Top Bottom