Economy 7 meter radio transmitter fault?

[ed-ectrician]

Hi there,

I'm scratching my head on this one. Client has a wireless radio transmitter thing next to their meter which sends a signal at 2330 to the main meter (two dials - one for economy7/off peak one for on peak/normal) to turn on economy 7 and then off again at 0630. Side note: apparently radio 4 sends this radio transmission out every night and morning! Pretty nifty huh?!

They are complaining that the immersion heater is cold every morning so economy 7 not kicking in I think, or a wiring fault. Put the economy 7 load side cables into supply of the boost FCU (there are two FCUs - one for boost one for off peak/economy7) and hey presto it works. also did continuity on both the elements and they both came up with 19 ohms each so elements intact. so it would seem that the problem is between economy7 FCU and main intake. I tested between the breaker that controls the economy7 heating and the economy7 FCU and there is continuity there live and neutral. Did continuity of cpc and IR tests too on the economy7 bit of the board just becasue i could! Both fine. The economy7 breakers are not RCD protected so no danger of that tripping out, anohter thing ruled out!

There is also an on/off switch on the radio transmitter by the meter that, when turned on (it was off) seems to override the transmittter and kicks the economy7 loads both on. i know this becasue i switched it on and tested for voltage between economy7 element intakes. Also when i turned it on the meter started spinning loads - prob becasue of the extra load in the water heater right?!

Ok maybe i did too many tests but wanted to be sure the immersion worked ok!

Next thing to do is go round there betwee 2330 and 0630 and seeing if, with the override switch off on the transmitter, there is 230 between live and neutral on the immersion heater's economy7 element.

Am i missing something glaringly obvious?!

I feel like I said eceonomy7 about a million times haha!

Thanks everyone

Ed

 

[Robotstar5]

Is there any form of indication the transmitter is working during E7 times? an LED or something you could ask the customer to look for.
Any form of external antenna on the transmitter/reciever that has become damaged or disconnected?

 

[ed-ectrician]

An LED was flashing all the time whilst i was there yesterday. It was a radio teleswitch series three. Just remembered the name of it!

 

[ed-ectrician]

Ps no antenna i can see. Looks like off peak fed 2 circuits- the immersion, a 20a mcb and then a 16a Mcb. Prob should've found out what that 16a one controlled! Thing is, electrically, everything fine from element to the intake of that breaker so it's got to be DNO issue right?! I forgot to say the plumber who gave me this job (good mate of mine) said the caretaker of the flats had a spark look at metering and said it's all fine. Not sure about this. I think it's a late/early callout next as i cant think what else it could be?!

 

[ed-ectrician]

Correction! Immersion was a 16 a breaker. The 20a one was a mystery. What could be on a 20a breaker and offpeak juice. DB completely void of any labelling! Nice! Newish flats in 'london's trendy shoreditch' but old wiring colours. Big statue of hitchcock in the middle of them! Surreal!

 

[polo1]

Correction! Immersion was a 16 a breaker. The 20a one was a mystery. What could be on a 20a breaker and offpeak juice. DB completely void of any labelling! Nice! Newish flats in 'london's trendy shoreditch' but old wiring colours. Big statue of hitchcock in the middle of them! Surreal!

20 amp breaker - Storage heater?????

 

[ed-ectrician]

Duh!! Yeah probably. Anyway, back to my original problem...

 

[snowhead]

It can only be a faulty Radio switch

You don't need to go overnight, take an off peak meter reading during the day then go back the next day and see if it's increased.

It's not a DNO problem, the meter and switch belong to the energy supplier.

Get the customer to ring whoever they are supplied by, say they've have the fault traced to the switch and the Supplier will come and fit a new meter which now incorporates the teleswitch.

 

[Robotstar5]

Just had a quick "google", is it a Horstmann? - link

 

[ed-ectrician]

yep that's the one. Found it on google last night. Must be faulty?

ANY other suggestions - dont want to look like a **** when the meter people come and tell me it's all working fine and I forgot to check the most basic thing!!

 

[snowhead]

yep that's the one. Found it on google last night. Must be faulty?

ANY other suggestions - dont want to look like a **** when the meter people come and tell me it's all working fine and I forgot to check the most basic thing!!

Meter people aren't that good..

 

[Octopus]

Last immersion heater I came across like this, I had to do a temporary connection to a socket, and use my clamp meter to prove the immersion worked. Next thing I did was to replace the FCU with a neon type, plus ask the customer to switch on a storeage heater. The next day they confirmed that neither the immersion, nor storage heater worked.

I sugggested the client contacted the supplier and submitted my invoice!

 

[drew35]

Just tell their electricity provider its as noisy as a bag of nails in operation and the customer is fed up with it, then they should fit a nice new digital dual tariff meter.

 

[ed-ectrician]

Thanks everyone. Felt like a bit of a failure not being able to solve the fault but sounds like i did all the right things and the problem is with the meter. From what I've heard meter fitters arent great so we'll see how much joy they have with them!

If I stick a neon on then I can indeed just ask the customer to tell me if they came on at half eleven. Very simple but good idea Murdoch. I love it when a plan comes together!

 

[Graham Hamilton]

I had a similar sounding problem and it turned out that the Horstmann Quartz timer's switching mechanism had worn down to the point where it no longer switched on the immerser. Everything else checked out fine.

 

[ed-ectrician]

I forgot to say I got 12 volts across live and earth and live and neutral with my voltmeter when I tested in "on peak" hours - (about 7 in the evening) - then with 'override switch' on as described above it tested out as 230v.

Is this normal - do you normally get a bit of voltage across these cables even when it's off?

 

[needasparks]

Yup, with a name like yours you should know that.

 

[UKMeterman]

If you got 12V L-N during peak hours and there was no smoke anywhere then I would think there is some problem between the imersion and the point you measured that voltage. Have a think why and then I will explain more.

 

[ed-ectrician]

Backfeeding/capacitance? Am i barking up the wrong tree meterman?!

 

[UKMeterman]

Well yes, it is all to do with things called a potential divider. If all you saw was 12V on your meter and your digital meter has typicaly a resistance of 10 million ohms, then something was provideing a very small current of 1.2 millionth of an amp 0.0000012A if the imersion heater was in circuit (all switches on, and no blown fuses in the airing cupboard) and wanting to heat the water (the thermostat was cold) then you would have seen a voltage of 0.000015V If the customer is still having a problem then go back to the property and do some dead tests;

1. Check at the consumer unit that you see 12.5 ohms ish L to N at the imersion CB when the imersion heater is switched on at the heater but with the immersion CB OFF. This should rise to infinity when the imersion heater is turrned off using the switch next to it.
2. Check that the neutral for the E7 consumer unit is connected to the neutral in the peak board.