On peak off peak wired incorrectly?

[MeganS]

Hi
Absolutely 0 knowledge of this so excuse language / terms / explanation.

Electric only ground floor 2 bed flat ( 3 external walls)

On peak and off peak switches for immersion (water in a tank…goes to kitchen sink , shower , toilet and bathroom sink) - to note - this water is boiling hot - have turned thermostat down multiple times, think we’re on around 30c now????
If I turn ‘ON peak’ switch off & leave just ‘OFF peak’ on we end up without any hot water to sinks and electric shower.

On and off peak switches for storage heater. If I turn ‘ON peak’ switch off, this turns the power off to the storage heater (this is wrong, am I right?) which inevitably then leaves the ‘OFF peak’ switch irrelevant and it’s not doing anything.

Please please please can someone help me with this. I have absolutely no knowledge, I have had 4 electricians round my house and none of them can solve this issue (is it for plumber or electrician or combined???)
My bill is absolutely sky rocketing (not just due to increases as it was this way when I moved into the property 2 years ago and I have tried multiple times to solve) to put this into context I am being billed approx. £350 a month for a 2 bed ground floor flat…. This has been before the price increases also, since 2020 when we moved here and again I should add during winter months so problem kid mainly with storage heaters I believe but also immersion on peak off peak is wrong I believe.
EON refusing to help - say not their fault?
Paying ‘call out’ charges to electricians who cannot help…
My house is becoming covered in mould as I cannot keep up with the bill to heat my home and ventilate it correctly (too cold now with winter and a waste of the heat)
Thanks

 

[timhoward]

I'm also shocked that 4 electricians haven't been able to play a fairly simply game of "I wonder what is supplying this" and make a little progress.

@MeganS I'll try and repeat what others have said in simple terms. As far as I can tell the original design was that the very right hand bit of your consumer unit is designed to be powered only during off-peak times.
So it looks as though the original design was for the storage heaters and the lower immersion to be powered at night.
The upper immersion was probably intended for obtaining extra hot water and likely was intended to be manually switched on and off as required.

(to complicate matters some modern storage heaters can also be wired to also be used during the day, but ignore that for now)

The primary goal for any electrician (as said above in various ways) is identifying how the off-peak supply to the lower immersion was intended to work when originally installed.
I'm 99% sure there is a cable from the consumer unit to one of the two marked switches.
I'm also fairly sure that it isn't now connected to where it was once connected, as the breaker is missing.

I could speculate that if the lower immersion became faulty, someone could have decided the fault was it wasn't getting power (mis-diagnosis if they checked during the day) and decided to give it power from somewhere else.

But any electrician is simply looking to find the cable that was originally connected to the very right hand space on your consumer unit, check which switch it goes to, and check that in turn is connected to the lower one.
They would need to re-fit the missing circuit breaker (MCB) too.

Once that is done, we get into secondary issues, like does the immersion heater and it's stat work, and how is the on-peak unit powered. But at least the on-peak could then be turned off to immediately save you some money.

If you don't mind, post whereabouts in Essex you are (roughly). You've been messed around so much that someone might offer to help, as the diagnosis should be a quick job.

 

[brianmoooore]

If there's no E7 or similar, then there should be a feed for the immersion heaters from the off peak section of the CU.
I'm beginning to wonder whether there was a fault on the off peak feed (missing MCB), and a simple work around, to get a full cylinder of hot water back, was to swap the bottom immersion to the non off peak switch in the airing cupboard.
A competent electrician should be able to work out what the problem is, but not necessarily fix it, within half an hour

Edit: Looks like timhoward and I have come to the same conclusion at the same time!

 

[marconi]

My earlier post was too cryptic. If you do not live far from the Dartford Crossing, which is 10 minutes away from me in Essex/Havering, then I will pop round and have a look at what's what and take some photos for the fine folk who have posted so far to examine. And I will give you my 'tuppeny worth' too. I will not do the remedial work but I will visit for free as long as you are within 30 minutes of the DC. It will get me out of the house. Being married to my dear wife for 35 years means responding to a damsel in distress is a speciality of mine Daytime please.

 

[littlespark]

My earlier post was too cryptic. If you do not live far from the Dartford Crossing, which is 10 minutes away from me in Essex/Havering, then I will pop round and have a look at what's what and take some photos for the fine folk who have posted so far to examine. And I will give you my 'tuppeny worth' too. I will not do the remedial work but I will visit for free as long as you are within 30 minutes of the DC. It will get me out of the house. Daytime please.

You didn't say how many sugars you want in your tea....

OP, you should take up this offer. Then you will be in a better position to inform your local electricians what the problem actually is.

And, it will convince you never to use any of those electricians that have visited already, if they cant figure out the problem.

 

[James]

@marconi
is one of the few people who actually understands electricity and how it works, If you have the opportunity to serve him a cup of tea, your endeavours will not be wasted.

 

[MeganS]

My earlier post was too cryptic. If you do not live far from the Dartford Crossing, which is 10 minutes away from me in Essex/Havering, then I will pop round and have a look at what's what and take some photos for the fine folk who have posted so far to examine. And I will give you my 'tuppeny worth' too. I will not do the remedial work but I will visit for free as long as you are within 30 minutes of the DC. It will get me out of the house. Being married to my dear wife for 35 years means responding to a damsel in distress is a speciality of mine Daytime please.

Apologies I missed replying to the message within the many lovely explanations from all the others.
I have sent you a private message with further details
Thanks so much

 

[baldelectrician]

My ex apprentice (now an excellent qualified spark) now lives in London and has his own company

Once Marconi has been I can send him a message.
I don't know if he is doing domestic work or not but I can check

 

[MeganS]

My ex apprentice (now an excellent qualified spark) now lives in London and has his own company

Once Marconi has been I can send him a message.
I don't know if he is doing domestic work or not but I can check

That’s very kind, thank you
I am catching up with Marconi via phone call tomorrow so we’ll update you all as soon as he’s had a look

 

[marconi]

First Megan and her baby were very pleased with the generous help and advice from those who responded . I visited today and took a few photos and found out a few things:

1. There is a time switched off peak supply controlled by the meter and connected to the far right off peak main switch of the CU. I saw this supply turn on during my visit. The first picture below shows the peak and off peak supplies to two FCUs for the one and only storage heater.

2. Both immersion elements are sound as are their thermostats. However neither thermostat is a safety 'stat. Both were set to 55C. I have recommended the rod 'stats are changed to safety stats. The elements are both 11 inch. Each elements draws 13A. The switches for the elements are wrongly labelled. The top one labelled off peak feeds the upper elements and the lower one labelled on peak feeds the lower element. But see a later comment at 5 below.

3. The 24 hour supply for the storage heater is fed from the flat FRC. The off peak supply is from the first rcbo (B20A) to the right of the off peak main switch.

4. All the wall dimplex heaters are fed from the flat FRC and thus from the peak supply side of the board.

5. The two immersion heater switches are connected to the same peak supply B20A mcb - the one above which you see my ampclamp. I confirmed this by turning both 'stats to maximum and my amp clamp measured 26A and mcb buzzed.

6. The 13A socket for the water pressure pump is spurred off the immersion heater switch above it - you can see the wago connections behind the switch above the socket. Whereas the flat us wired in old colours the paralleling of the immersion heater switches and socket is done in new colours. The supply to all three from the board is the original old colours.

7. The second right B20A rcbo on the off peak supply says it is a for heater on the outside of the board bit is marked up with 'Imm' inside. I don't have a picture for that. There is an old colour cable connected to it but I could not establish where its goes. I suspect it is terminated in connectors behind the lower immersion heater switch or the 13 shower pump socket but I could not see if this was the case. I did not look behind the surface mounted 13 A socket - all a bit too awkward for me to do. Disconnecting this cable run, it measures open circuit between L-N.

8. I did not check how the lounge storage heater programmer was set up.

In brief then the only Eon controlled off peak heater is the storage heater in the lounge. Whether water heating uses off peak is by chance because Megan did not know that the whole flat (ie all the peak side loads) uses the lower tariff when it switches. (She has E10 which I checked on her bill). A phone call to be made to determine the off peak time slots but I have passed what I think they maybe and how to detect when off peak is available - the lounge right FCU neon light. The shower is fine albeit the flow rate is low which means that on the highest power setting the water temperature is too hot to bear. On the low power setting the water temperature is fine for a bloke but perhaps not hot enough for a damsel ;-). On the cold setting the water is cold and there is only a cold water supply to the shower.

The major work it seems to me is to provide peak and off peak supplies to the two IH elements, swap the stats to safety ones and provide a dedicated FRC supply perhaps for the shower pump 13A socket - or fit an fcu spurred peak IH switch.

I have to sign off now as wife home from hospital.

PS: I left the board with some postits on it but forgot to take a photo.

 

[littlespark]

But the question remains....

How many sugars?

 

[marconi]

So it’s wired --- over t!t, then?

Sort of. The tank elements only have one shared feed using one 2.5mm2 cable off a B20A on the peak busbar. I have advised Megan only to use one element at a time. Something has happened in the past to make this so and to change the pattern/brands of the IH iso switches.

 

[brianmoooore]

The extreme RH MCB position on the CU is blanked off and marked spare, but was originally labelled 'immersion'. Is there any evidence inside as to what this might have been about?
You say both switched cable outlets for the immersion heaters are connected back to the CU by a single 2.5mm2 T&E. Does the feed go to one and then spur on to the other? If so, does this look original?

 

[marconi]

The extreme RH MCB position on the CU is blanked off and marked spare, but was originally labelled 'immersion'. Is there any evidence inside as to what this might have been about?
You say both switched cable outlets for the immersion heaters are connected back to the CU by a single 2.5mm2 T&E. Does the feed go to one and then spur on to the other? If so, does this look original?

1. Theis new MK CU was installed when Megan moved in.

2. I suspect strongly that the RH mcb position you mentioned was for the off peak IH element. It is now fitted second right to off peak MS but does not power anything. I reckon one of the original three B20A rcbos (two for SHs and one for off peak IH) on the right of the off peak mainswitch has been moved to the right of the far left peak main switch to supply the hall dimplex.

3. After Megan bought the flat but before she moved in the electric space heating was renewed in toto.

3. The original red black 2.5 mm2 feed from peak side B20A marked IH arrives at top IH iso. Spurred off it in brown blue is a drop to the lower IH iso. Spurred off lower IH iso is a drop to the new 13A socket for the water pump.

 

[brianmoooore]

So it's looking likely that the conclusions that timhoward and I came to at exactly the same time, in posts 31 and 32, that there was a fault with the off peak supply to the lower immersion are correct? This was then bodged to get the lower immersion working again, most likely without telling the customer that the cost of water heating would be doubled.

 

[Avo Mk8]

The single feed to the immersions could perhaps be used as is by installing a Horstmann Economy 7 type controller, fed from one of the existing FCU's, which could output to the two immersions, as it ensures only one can be powered at any one time. So setting the timeclock to E10 periods would power the bottom immersion on cheap rate, and the rest of the time the boost button would be available for a top-up, on peak rate of course.
But does the pump draw too much to be left on that citcuit as well, I guess it doesn't consume much?