Solar Immersion - my experience !

[danesol]

Yes, the £199 offer was the trigger to buy two!

Re the neon puzzle, I'm as certain as can be that all three of our immersion stats are working properly. The neon intensity certainly varies according to the feed from the SI during daytime with the PV switched on, and both installations are performing according to specification, supplying piping hot water, in my own case to two HW cylinders with the changeover from Heater 1 to Heater 2 running smoothly and rather impressively. These SI units work and we're very happy with them!

But at night, (or in daytime with PV switched off for test purposes) the neon on the immersion switch glows at full intensity when the water temperature is at or in excess of the stat temperature. This is happening on both our installations. Running off hot water to drop the cylinder temp below the stat setting immediately extinguishes the neon, which then stays off until the PV feed via The SI kicks in again in the morning.

To be honest, I'm more curious than concerned. If all that's happening is a feed to the neon overnight I don't think it's going to break the bank, but I would like an explanation, simple enough for a mere layman to understand, of why this should be happening!

Can I also assume you have wired exactly how I believe its stated in the installation manual for two SI units to be joined together ?

You also mention three immersion stats but only 2 cylinders or should I say heater 1 and heater 2 - so where's the third stat ??

I assume you did the very basic test for correct direction of CT Clamp, possibly using only one immersion heater for initial setup just in case two jopined together alter the findings or result ??

 

[Sunstroker]

Now hold on there! Who mentioned two SI units joined together? I thought my initial post made clear we are dealing with two separate installations in two different properties.
My own house has two HW cylinders, each with a 3kW immersion, My son has one cylinder and one 3kW immersion. Both properties have 3.7 kWp PV systems, and both have central heating systems powered by a combination of woodburners and either LPG or oil-fired boilers. All of which is irrelevant to my initial query re the immersion switch neons, apart from the fact that we both have the ability to heat the water in our HW cylinders up to a temperature in excess of the setting on the immersion thermostat.

I find it difficult to believe that our two SolarImmersion installations are the only ones exhibiting the neon-lighting peculiarities which I have described. The fact that they both do it suggests to me that this must be a feature common to all installations. Has nobody else noticed it?

Of course, the obvious people to answer my query should be the manufacturers, but they remain totally unresponsive.

Unlike their SI units, which thankfully continue to perform immaculately!

 

[Worcester]

If the neons are light they MUST be receiving power from some source. Do the SolarImmersion units have a boost / override timer function? If so has this been set?

 

[Sunstroker]

I agree, we have not achieved the holy grail of spontaneous generation so the power to light the neons must come from somewhere. Presumably from the mains via the SolarImmersion unit, since that is now the only connection which exists.

The SI units do have a manual boost function, they also have an Economy 7 setting, and my first thought when I noticed the lit neons was that one or other of these had been enabled, but they are definitely both set to off. It appears that only the neon is lit, the immersion is not consuming any power, indeed how could it when its thermostat has cut out? And, as previously stated, as soon the water cools and there is demand from the immersion the neon goes off and stays off until the SI starts to supply PV surplus power next morning.

 

[danesol]

If the neons are light they MUST be receiving power from some source. Do the SolarImmersion units have a boost / override timer function? If so has this been set?

They do and thats a possible too - good thinking.... although I would expect bright neon on activation of overide ??

 

[danesol]

Now hold on there! Who mentioned two SI units joined together? I thought my initial post made clear we are dealing with two separate installations in two different properties.
My own house has two HW cylinders, each with a 3kW immersion, My son has one cylinder and one 3kW immersion. Both properties have 3.7 kWp PV systems, and both have central heating systems powered by a combination of woodburners and either LPG or oil-fired boilers. All of which is irrelevant to my initial query re the immersion switch neons, apart from the fact that we both have the ability to heat the water in our HW cylinders up to a temperature in excess of the setting on the immersion thermostat.

I find it difficult to believe that our two SolarImmersion installations are the only ones exhibiting the neon-lighting peculiarities which I have described. The fact that they both do it suggests to me that this must be a feature common to all installations. Has nobody else noticed it?

Of course, the obvious people to answer my query should be the manufacturers, but they remain totally unresponsive.

Unlike their SI units, which thankfully continue to perform immaculately!

LOL

Anyway - I cant notice this on my installation as mine is wired directly from the existing spur and given that both your units operate correctly and efficiently I can only assume its down to how the units sensor the mains using their own wave form technology, if it is I doubt you will get the company to reveal this ...... ??

I do however notice occasional spikes during the night but as the monitoring device wont work properly now since SI fitment I have not investigated this further as the unit appears to be working fine and my bills dynamically reduced the last few mths, especially GAS

But I agree - if part of how the device works, it would be interesting to know why.......

 

[Sunstroker]

Breaking news!


Yesterday I was curious regarding an unexpectedly lit neon. Today I see no neon lights at all. The SI unit has failed! The LCD still indicates power diversion to Heater 1 or Heater 2 but the immersion switch neons remain unlit, and the water cold.


I have contacted the manufacturers who confirm that the unit has definitely failed, and no on-site repair is possible. So the SI unit has been removed and will be despatched tomorrow. They say that it will be replaced by an updated unit, so it would seem that development is still ongoing.


Watch this space!

 

[Mulgrave]

Hi
contacted solarimmersion few months ago because my mark ii was not working.Never managed to get hold of the concerned staff, online chat help told me , he has no experience with mark II, the one knowing abt mark II was travelling to china to order units ( supposed to be made in the UK) they never reply to messages. I just gave up with them, lost over 300 pounds for mark II + power reducer+ all tel calls.

 

[danesol]

Hi
contacted solarimmersion few months ago because my mark ii was not working.Never managed to get hold of the concerned staff, online chat help told me , he has no experience with mark II, the one knowing abt mark II was travelling to china to order units ( supposed to be made in the UK) they never reply to messages. I just gave up with them, lost over 300 pounds for mark II + power reducer+ all tel calls.

To be blunt, I wont lose £300 for no-one, you used your well earned and probably already "taxed" money on a product which you have issue with, why would you give up chasing this so easily ??

 

[Mulgrave]

To be blunt, I wont lose £300 for no-one, you used your well earned and probably already "taxed" money on a product which you have issue with, why would you give up chasing this so easily ??

Hi

i gave us using their product but I am still chasing them for a refund. I contacted them for a refund but they have not replied. I contacted their main office , sent many emails but still no replies.
Tushar is always travelling and never answers his phone.

thanks.

 

[danesol]

Hi

i gave us using their product but I am still chasing them for a refund. I contacted them for a refund but they have not replied. I contacted their main office , sent many emails but still no replies.
Tushar is always travelling and never answers his phone.

thanks.

Well two on this thread seem to have had issues resolved by email/voice contact already, so I would keep trying if I was you.....

 

[danesol]

OK UPDATE, the GAS boiler is now back on due to the recent weather... so that's a definite 6mths of using NO gas at all to heat the HWC, saving 1,346kwhs of GAS equal to ~ £ 46 saving


I have a way of measuring the divert now, so should know exactly what the SI diverts from the Solar panels over the Autumn and Winter mths, which will give me the full extent of what actually is been saved.

 

[Worcester]

Isn't the daily / monthly/ yearly savings one of the display functions on the SI then?

 

[danesol]

Isn't the daily / monthly/ yearly savings one of the display functions on the SI then?

LOL, sadly NOT so if you want info' to substantiate your purchase or backup the pub-talk .... your out of luck !

I should imagine - extensive reporting will be part of the MK IV ?

As they say you get what you pay for, but I am really pleased with my mk3 purchase and its saving both resources and my money, which is very apparent from recent bills, reporting is nice but at the end of the day, as long as its saving you monies, that's what its all about.

 

[danesol]

Yes, looks like the GAS is to stay on now with this terrible weather, but the SI unit is nicely preheating the water as and when it can - come on Mr Sun, show your face - 161watts just isnt good enough ! lol

 

[Sunstroker]

You may recall that I reported that my SolarImmersion unit failed a week after installation and was returned to the manufacturers, who promised an upgraded replacement. Well, 21 days and three phone calls later the replacement duly arrived and is now refitted and working. The reason given for the protracted delay was that they were awaiting delivery of the upgraded components. The unit arrived with a note thanking me for my patients (sic). Let’s hope their electronics are better than their spellchecker!


The second unit in my son’s house continues to function satisfactorily. It is powering only one immersion, my own is driving two, and there was a suggestion from the SolarImmersion contact to whom I initially reported the failure of my unit that this might be the reason for its failure. Not exactly reassuring!


The immersion switch neon still glows at full intensity when the water temperature in the HWC is higher than the setting on the immersion stat and the PV is off, so the upgrade hasn’t addressed this peculiarity, but if that’s the only quibble we can live with it.


As I mentioned earlier, the reason for the superheated water is the presence of an efficient woodburning stove in my system, and it is clear that the SolarImmersion will only really have a dual immersion water heating job to do in the summer months, when the woodburner is out. It burns more or less continuously from October to April, supplying most of my central heating and ample hot water for my needs. (I am fortunate in having an ample supply of effectively free firewood).


But the winter sunshine will still supply surplus PV power, so how to use it? I propose substituting a storage heater as the secondary load, instead of one of the immersions. Any ideas on how best to wire such a setup? Can I use a changeover switch? Given that I now have a spare slot in my CU where one of my immersions used to be I presume this could be used as the feed for the storage heater.
I haven’t discussed any of this with my sparky so far, and no doubt he will have his own ideas as to the best solution, but I’d welcome suggestions to throw at him!

 

[danesol]

But the winter sunshine will still supply surplus PV power, so how to use it? I propose substituting a storage heater as the secondary load, instead of one of the immersions. Any ideas on how best to wire such a setup? Can I use a changeover switch? Given that I now have a spare slot in my CU where one of my immersions used to be I presume this could be used as the feed for the storage heater.
I haven’t discussed any of this with my sparky so far, and no doubt he will have his own ideas as to the best solution, but I’d welcome suggestions to throw at him!

Did you action this at all ??

 

[Sunstroker]

Yes, and all is working well, or at least it would be if the sun would shine a bit more. 233Wh yesterday! I'd get more heat from a tealight!
I see someone else has discovered my "lit neon" syndrome, so it would appear that this is common to all SI units.

I mentioned earlier that one of our two original units failed and was eventually replaced by an "upgraded" one. I notice a slight difference between the two units. With the first one, the immersion switch neon glows steadily when the unit is diverting, irrespective of the rate of diversion, whereas the upgraded unit produces a flickering neon on the switch, and the diversion rate appears to vary in a cyclical fashion according to the unit's LCD readout.

Communication with the manufacturers continues to be frustrating. I phoned and asked for a proper VAT invoice, as I was only supplied with a Paypal receipt, but despite promises nothing has materialised. I fear for any kind of long-term support.

 

[HJG1]

A word of warning. Have purchased the Solarimmersion via their website on 21st April 2014. Received email notification of dispatched item 24th April ,but in fact they had not actally sent to item at that stage. Eventually received the item the following week only to find the item was faulty staright out of the box. The triac was actually broken from the unti so it was obvious straight away. Phone company same day- they could not sent a repalcement that week so I cancelled the order for full refund. Item was sent back and I waited , and waited for refund- none came. I email and phoned, but no refund. Had to go via Paypal to get my money back- event hen the company did not respond.
Now have an Immersun II installed and working perfectly. Lesson learned- pay a bit more for quality and service!

 

[nielfrancis]

Hi there,
Read this and checked with a couple of my electrician friends who are using Solarimmersion. They found it somewhat strange when I mentioned about the "triac" as there is no triac in it. They have been using it since a year and are happy with the results.
Sad to hear your experience although good luck with your new choice!

 

[danesol]

I've managed to organise a discount code for forum members for these units !!!

So if you are going to order one in the foreseeable future - please use the following code on checkout;

dis2204





SolarImmersion - Surplus Solar Energy Water Heater |

Well over 12mths on, the unit is working well and making use of every bit of surplus energy in the property. The GAS boiler which heats the DHW normally is off completely and has been since the spring equinox - really pleased with the unit todate.

 

[MicraShed]

I have the Immersun and some days just cant physically use the hot water it produces.

Increasing the tank insulation has meant water dropping from around 70 degrees to about 50 overnight - some of that cooling is due to cold water filling the DHW tank after a night time bath.

I too have had my GCH switched off since April.

 

[tdrees]

Hi Folks, I have just turned up my solar immersion III last week. As with others, lots of hot water!


Power is being successfully diverted to the immersion heater, and the load balanced with input reasonably well.


Two issues I would like to correct.


1) When the solar output drops suddenly (cloud cover) or the house load increases (kettle), it can take some time for the solarimersion to recognise the change and reduce or cease diversion to the immersion heater. I have the "export level" setting configured to "20w" to give some buffer, but the balance point seems to be around ) (judged by looking at my household meter (spinning disk variety). The unit is installed in the airing cupboard after the power switch to the immersion and has UTP cat5e cable connecting it to the sensor.


Are there any settings I can adjust to improve the PV output matching?


2) Due the the nature of my PV set up (east west house with 2 banks of panels) my peak output for my system is about 2.2Kw, but usually around 1.8Kw. As I am writing this (9:40am) I am seeing about 1300w from the PV. My base house load is between 300w and 400w (too many standby gadgets) so I have at peak around 1.5 to 1.9Kw inject into the tank.


The Solar immersion display seems to divert starting at 8% and then 13%. I have seen a situation where the unit oscillates between 8% and 13%, alternatively exporting an importing from the grid.


If I set the immersion heater load at 1500W, will i get better quantisation on the export balancing?


Anyone know?

 

[danesol]

Well I 've set my unit up exactly how it tells you too in the manual(s) and i have no issues whatsoever - ours reacts immediately !

The only option we haven't had chance to utilise yet is the 2nd output

 

[tdrees]

Thanks Danesol,

Mine is setup as per the manual too. Perhaps there is an element of distance from the sensor, as we are using the cat5 extended model rather than a short link to the meter box and long tail to the immersion.

I am interested to know if anyone else sees the "ossicaltion" when exporting small amounts of power.

Tobes

 

[danesol]

Ours too is in the airing cupboard "miles away" from the dno meter / Henley Block so using a considerable amount ofcat5 via the loft and down the gable end, the length of tbe cable shouldnt actually matter unless it exceeds that of cat5.

The only issue we have if you can call it that is that once the SI unit kicks in no RT clamp / monitor records the true electrical consumption properly but this has been discussed before possible on this thread?

As yet I am yet to find a monitor system that can wirk alonvside this unit and measure accurately the true consumption

hth

 

[tdrees]

Again - thanks for the feedback! .

I have noticed the same thing, the Electrisave monitor that we have is hopeless when the real power draw is close to zero, as you would expect. Its very hard to measure a magnetic field that does not exist! It seems to revert to "last reasonable measurement" which is invariably something large caused by the kettle having been turned on.

 

[Worcester]

And then you guys still wonder why we wont fit these particular units!

ImmerSun's and Apollo's for us Choice is dependent upon the functionality needed. - As we fit more and more heat pumps, we're doing more and more solar, and more and more ImmerSun's - Standalone we find the Apollo's difficult to beat on value and performance.

 

[Steve_rutland]

For anyone who has solar, I would definately recommend an Immersun. I haven't used any gas since mine went in!

 

[danesol]

Again - thanks for the feedback! .

I have noticed the same thing, the Electrisave monitor that we have is hopeless when the real power draw is close to zero, as you would expect. Its very hard to measure a magnetic field that does not exist! It seems to revert to "last reasonable measurement" which is invariably something large caused by the kettle having been turned on.

The real stupid situation I have is that I am currently using two complete E-On energy monitor systems ( Current Cost ) , one hooked up to the tail after the Henley, but feeding the CU and the other on the tail between the DNO meter and the Henley Block.

........ now this is the interesting bit !

When the SI unit kicks in when the consumption in the property is less than the generation and that generation is around the 2kw mark - the value of the two monitors gives the precise consumption with one been alot higher than the other, ie one appears to measure what the SI is sending to the water heater and the other is what the standby useage... LOL


When the PV system is generating far less than this amount - the two read very similar figures !

As I can only connect one of these to my PVO uplink system - the figure I record / send is inaccurate but over the course of a mth isn't that far out ... now work that out !


edit:- Forgot to mention - I also try and measure the load on the positive tail from the SI to the Immersion Heater to try and see how much is been diverted - I use an old British Gas wireless unit for this which is also hit & miss for the very same reason. I know this is the case as I can see what im generating, what I'm using and can also see the DNO meter is stationary so know exactly when its lying to me and not recording diverted electric to the IH !

 

[MikeWBC]

I have a very similar setup to trdees, and I'm getting exactly the same effect. I have a Solar Immersion feeding a 3Kw immersion heater and East/West solar PV installation. Even if I have 1800W being generated, with a base load of 300W, the monitor measuring total consumption varies between 300W and 3.5KW. The SI oscillates between 8% and 13%.
I only installed the SI 2 months ago, and with fairly stable weather conditions, I could get an accurate comparison before and after. Measuring the gas saved and the extra Solar power used, it appears the Solar Immersion imported 25% of its power from the grid.
So I've saved 79p in 2 months.
Support at Solar Immersion have said this new model now uses the burst fire (power burst) form of control, which I believed could cause flicker problems, rather than phase control.
Hasn't Immersun just gone the other way?
All Support at Solar Immersion can offer is to swap the unit for an old model.

 

[Sunstroker]

I’m confused! It appears that some are suggesting that their SolarImmersion units may at times be importing from the grid. Surely this can’t be so?


Up until now I have assumed that when the SI display indicates a diversion percentage this is the proportion of total available solar power that is being diverted, not the percentage of potential demand being supplied to the load. How can the SI unit “know” the wattage of the load?


In my case Heater 1 is a 3 kW immersion while Heater 2 is presently a 2.7 kW storage heater. There is surely no way that the SI unit can detect these differing loads, so the display can only be indicating the percentage of total generated power being diverted at any given time. If there is no surplus from the PV system then nothing goes to the load and nothing is imported. That is the whole purpose of the system.


On a different point, MikeWBC states that Support at Solar Immersion have said the new model now uses the burst fire (power burst) form of control, which could cause flicker problems, rather than phase control. This would possibly explain my previous observation that my replacement unit causes the immersion switch neon to flicker, while the original unit in my son’s house produces a steady neon irrespective of the rate of diversion. I have to say however that I have not noticed any problems of flicker in my house lights.

 

[MikeWBC]

Thanks for your comments, Sunstroker. To answer your points, as I understand it, the percentage shown on the display is the percentage of the full sinusoidal waveform that is being fed to the load. In a phase switching system (like the old SI unit) the output thyristor (probably a Triac) is fired so only a percentage of the 50 cycle waveform is fed to the load, so for 20%, the triac fires late in the cycle and for 50% it fires at the mid point. A problem with this is that the fast switching injects harmonics into the mains, which can cause electromagnetic interference unless filtered out.
Burst fire is different in that it feeds full cycles to the load, but only intermittently. So for 13% only one in 8 cycles are fed to the load. This means current is being taken in 20mS bursts every 160mS which is about 6 cycles a second, well within the visual “flicker” range, but is only likely to manifest itself if the supply to the local group of houses is relatively poor. And your neighbours have got their lights on. If you’re on an estate or in town, you’re unlikely to experience any flicker problems.

The unit doesn’t need to know the wattage of the load. As I understand it, the old SI unit simply increased the power to the load in 10% steps until the sensor detected the export power was in the minimum range set, and then checked it every second or so.

My guess is that the problems with the new burst fire unit are to do with the sensor. In the old system, the sensor circuitry only had to average out the current for a couple of cycles or so, say 50mS, to get a reasonably accurate reading of the current flowing.

It’s much more difficult with burst fire, where it needs to average over 20 or more cycles.
If they’re sampling much shorter than this, a likely scenario is that the unit sets an output, samples and sees power being exported, so it increases the load, samples again, still sees export and increases the load and so on until it hits a burst. By this time the load has exceeded the available solar power so some is imported.

I monitor and record my usage, generation and import readings, and my usage is fairly constant over the year. So it was fairly simple to see the change when the new SI unit was fitted.
For the two months before I only used gas for cooking and water heating. For the 2 months after, I turned the boiler off.
The extra solar energy used was 166KwH
The extra electricity bought was 64KwH
I saved between 7 - 8 Units of gas = 220KwH - 250KwH
So 230KwH seems about right for water heating.
So it's saved me 230x0.032 = £7.36
But it's cost me 64x 0.108 = £6.91 in extra electricity.

Sorry it’s such a long tome.
Mike

 

[Sunstroker]

Thanks for the comprehensive explanation, Mike. Your understanding of the complexities of electronic switching far exceeds mine, but I think I understand the gist of it. My degree, a long time ago, was in agricultural economics, and we didn’t cover sinusoidal waveforms!

I know how much my PV system generates per day (8.98 kWh on average since installation in Jan 2011) and how much I import per day (6.51 kWh over the same period). My daily average usage prior to PV installation was, incidentally, 12.53 kWh, so I’m happy that there is a considerable saving.

But I gave up trying to keep track of ongoing import and export when the SI unit was installed as the display on my NPower Smartpower monitor seemed fairly meaningless when the SI unit was diverting. I simply assumed, perhaps mistakenly, that the unit was doing its job. My water is hot, my storage radiator likewise, at least when the sun shines, and as far as I can see I’m not importing more than I did before the SI unit was installed, so in my case it does appear to be worthwhile. Perhaps if I had additional monitors to measure all the parameters I might feel less happy, but I think I’ll remain content in my ignorance for the present!

As regards flicker, my house is rural, with only one other property fed from the same transformer, and neither of us have noticed any problems with flickering lights since my SI unit was installed. My existing unit, an eventual replacement for the initial one which failed in September 2013, was delivered last November so I presume it is the latest burst fire type.

 

[SibertSolar]

Of course, you could always use an Elios4You and Power Reducer in tandem - you would have all the generation, consumption, import & export monitoring/data you could need, and a safe, compliant and compatible immersion controller designed by the same manufacturer, with no issues surrounding burst-fire or phase angle control....but then that's just me being biased....

 

[MikeWBC]

Thanks Sunstroker, it could be your replacement is still of the old variety. My original failed at the beginning of June (this year)and it took to the end of July to get a replacement out of them. Their excuse was that the new model was just coming in. I'll keep monitoring mine, but I don't hold out much hope of any resolution from them.
Cheers

 

[Gavin A]

Of course, you could always use an Elios4You and Power Reducer in tandem - you would have all the generation, consumption, import & export monitoring/data you could need, and a safe, compliant and compatible immersion controller designed by the same manufacturer, with no issues surrounding burst-fire or phase angle control....but then that's just me being biased....

and fit a NEDAP power router and 600Ah 24V battery pack in tandem with that to really exploit the full self consumption thing.....

 

[MikeWBC]

I’ve been looking at Power Burst or Burst Fire systems in more detail, and I’ve come to the conclusion that it’s inherently flawed and can never work properly. I was wondering if someone on the Forum could please check I have my reasoning correct?
In a Power Burst system, you feed power to the load for one cycle every “n” cycles, the ratio depending on the load wattage and the power available from the PV system. So, for example, with a 3KW Immersion heater, and say 1KW available power from the PV, you would burst one cycle every 3 to the load. During the burst, you’re providing 12A at 250v to the load. The PV has 4A available, and regulates this by dropping the voltage to compensate, so 8A has to come from somewhere, and is imported from the grid. Then for the next 2 cycles, while the burst is off, the PV exports 4A to the grid. So 667W (67%) of power going to the immersion is imported from the grid, and the PV has exported an equivalent back to the grid. With a digital import meter, it will register the imported power, but not the exported power, so you’re buying the extra power from the grid.

And it gets worse, the lower the amount of PV power available.
At 3KW available, nothing is imported from the grid.
At 2KW available, 33% is imported from the grid.
At 1KW available, 67% is imported
At 500W available, 83% of the power is imported.

Have I got this wrong?

 

[Gavin A]

the meters aren't sensitive enough to register consumption at the per cycle level.

but what you've just described is why burst fire systems can not meet the flicker regulations and are therefore illegal to connect to a 3kW load in many situations - ie higher grid impedance situations, or IIRC anywhere that a 3kW load would result in more than a 0.7V fluctuation in the grid voltage. I've known some places where 3kW would equal 4V swing, and where this does cause lights to flicker badly enough to send an epileptic person into fit, and properly did my head in while working to pull the unit back out again.

 

[MikeWBC]

Thanks Gavin A, but the power has to come from the grid, since the PV system can't provide it, so even if the meters average it out over many cycles, it will still register as a power import, even at a lower level. Perhaps that was why my system only indicated a 22% increase in usage.