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Question

Is our Emmersion Heater not working due to RTS switch off?

  • March 2, 2026
  • 28 replies
  • 260 views

  1. Our Hot water tank no longer works since January this year (2026).
  1. Heating engineer checked the tank and said we must contact OVO because he reckoned OVO must have switched off our RTS signal.
  2. Twice we have explained as best we can on the phone to OVO our problem.
  3. In the first call to OVO customer services we were advised that the necessary software modifications had been made but if after 72 hours our normal Off-Peak service for the Immersion heated hot water tank still wasn’t working we should call the Technical department ( for which they gave us the phone number).
  4. After five days (well above 100 hours) the hot water tank still wasn’t working.
  5. We called OVO Technical department and were advised that everything was working at the OVO end. But how does this help if we still don’t have our hot water tank working?
  6. Can anyone suggest what to do now?

 

28 replies

Firedog
Super User
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  • Super User
  • March 2, 2026

Heating engineer checked the tank and said we must contact OVO because he reckoned OVO must have switched off our RTS signal.
  

OVO don’t control the RTS signal - the local Distribution Network Operator does. There are few places left still relying on the RTS.

  

In the first call to OVO customer services we were advised that the necessary software modifications had been made …
    

This sounds as if you no longer have an RTS system (whose software can’t be modified remotely) but instead have a relatively newly installed smart meter (whose software can be modified remotely).

  

We called OVO Technical department and were advised that everything was working at the OVO end.
  

This points to something wrong at your end. To be able to help, we’d have to see some photos of your meter etc., ideally:

  • a close-up of the meter itself (with the display lit up by touching a button if necessary) clear enough to be able to read the display and the markings on the meter itself;
  • A view of the whole backboard so we can see the main supply cable coming in from outside, and all the cables to and from the meter itself;
  • If it’s not clear from the previous photo, a close-up of the meter exchange label - the card left by the engineer giving the numbers and readings of both the old and new meters (assuming he did leave one, as he’s supposed to do);
  • A view of each consumer unit (fuse box) clear enough to be able to read any labels the electrician may have left to say which breaker is which.

This may help us to get to the bottom of the problem and make it possible to suggest a remedy.

 


  • Author
  • Rank 2
  • March 2, 2026

The smart meter outside the house was installed many months ago. I am trying to upload photos but technology is against me. 

 


Blastoise186
Super User
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If you need to, feel free to fling the photos to forum@ovoenergy.com and ask the Forum Moderators to upload them for you. We don’t charge for that! :)


  • Author
  • Rank 2
  • March 2, 2026

Next photo 

 


  • Author
  • Rank 2
  • March 2, 2026

 


  • Author
  • Rank 2
  • March 2, 2026

Photos that I took last week at night 

hence the shadows... today I fairly hurt my back with twisting and bending to take the other photo and I'm not about to further injure my dilapidated discs. No, no. 


Firedog
Super User
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  • Super User
  • March 3, 2026

Thanks for the pictures, and sorry about your injuries … 

The type of meter you have is usually used where the heating benefits from lower-price offpeak electricity. The equipment involved is then fed by the fifth cable from the meter (yours has three orange collars), which switches the power on and off at the right times.  If your heating is like this, e.g. night storage heaters, is it working properly? The immersion heater will normally be on the same circuit, so if space heaters are working but water heating isn’t, your electrician should be able to trace the cause - which isn’t within the meter.

We’ve seen two examples where the symptoms were similar to yours. The customer’s electrician solved the first in a couple of minutes, by resetting the immersion heater’s circuit breaker that had tripped. The other involved a faulty neutral (blue) connection, again quickly spotted by the attending electrician.

Let’s see the consumer unit(s).

  


  • Author
  • Rank 2
  • March 4, 2026

OK, one point I would like to be made clear to me before I post the consumer units... Is this little black box a smart digital signal booster or could it possibly be an RTS piece of kit?

 


Blastoise186
Super User
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Nope! That’s just an earthing point - it’s unrelated.


  • Author
  • Rank 2
  • March 4, 2026

So we can definitely rule out the notion that we have any Radio Teleswitch device, physical or otherwise? 


Firedog
Super User
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  • Super User
  • March 4, 2026

RTS changed a bit over the three decades it was being installed in peoples’ homes. In some cases, the RTS receiver was built-in to the meter; in others it was a separate device, sometimes near to the meter but quite often somewhere else entirely. We can’t say, then, from the pictures you’ve shared whether every scrap of RTS gear has been removed from your premises. We can say with certainty, though, that RTS is no longer in control of your electricity supply. 

 


  • Author
  • Rank 2
  • March 4, 2026

The consumer units 

 


Firedog
Super User
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  • Super User
  • March 4, 2026

Thanks - but oh dear! There should be a jargon-busting glossary page at this site that explains the sometimes impenetrable technical terms surrounding energy supply and use. 

These latest screenshots do indeed show ‘units consumed’ and recorded on the two registers inside the meter. You’ll realize that Total Active Import is the sum of the other two figures, labelled (I expect - the labels aren’t legible in your pictures) TOU Rate 1 and TOU Rate 2. In a perfect world, TOU Rate 1 will always be the ‘peak’ register for expensive, daytime usage, but that isn’t sadly always the case. We’ll get to that later.

I asked to see photos of “… each consumer unit (fuse box) ...”. By that I hoped to indicate that what we used to call the fuse box now has a new name, Consumer Unit. This is what it may look like with its lid open if it’s less than 20 years old or so:
  

All of the circuit breakers in this unit are in the OFF position. 

 

That’s what we’d like to see. There is often more than one consumer unit, especially when there are separate constant and switched circuits.    

 


  • Author
  • Rank 2
  • March 4, 2026

You can't help me, I know what a fuse box looks like, pointless going on with the discussion. but thanks for your endeavours well meant I accept. No harm done. Now all that remains is to continue going round and round like a dog chasing its tail. 

Totally give up. 


  • Author
  • Rank 2
  • March 4, 2026

Well, now that I’ve had a bit of time away from this perplexing situation, I think it won’t be a bad idea to provide further info on this strange morass. 

Let’s begin with a 30-odd year old ‘Fuse Box’ or ‘consumer unit’ if preferred! 

Whether or not this assists the puzzle presently underway - I honestly have my doubts.

But here goes with the requested photo. Looking directly at the photo the lower left ‘box’ is where the four trip switches are located. Three fuses belong to our 3 storage heaters and the fourth fuse is part of the hot water tank standard immersion circuit. We are presently using the booster immersion heater and its fuse trip switch is located on the top right hand side on the row of six fuses. At the risk of being told we need the house rewired here is the photo!

 


Firedog
Super User
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  • Super User
  • March 4, 2026

That’s brilliant! In fact, I’d say it’s more or less just what I expected. The bottom left unit is protecting the switched circuit, which is only energized during offpeak hours. The top unit protects everything else on the constant circuit.

Now we know there are storage heaters, my question remains unanswered: “If your heating is like this, e.g. night storage heaters, is it working properly?” 

  • If it is working properly, there’s a fault with the lower immersion heater, its controls or wiring. That calls for an electrician to investigate and fix;
  • If it’s not working (the heaters aren’t charging up as expected), there is a problem with the switched circuit. If this is the case, there will be more questions, to establish just where the fault is hiding.

What are the offpeak times for the tariff you’re on? They should have been given in the notification you had about it, and with any luck they will also be laid out on your Plan page. 

Do you have a working IHD that came with the new meter? That may come in handy for the next round. 


  • Author
  • Rank 2
  • March 5, 2026

Thanks for your responses. I may just wait for OVO engineer to check out the whole business when he arrives on 25 March. But I will reserve the right to cancel even that appointment.

My confidence in smart meter engineers and hot water tank engineers is currently very, very low. 


Firedog
Super User
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  • Super User
  • March 5, 2026

I may just wait for OVO engineer to check out the whole business ...

My confidence in smart meter engineers ... is currently very, very low. 
 

A couple of points in response:

  1. A meter engineer isn’t (necessarily) an electrician. Some of them are. Meter engineers know a lot about meters, meter tails, communications hubs, cut-outs, backboards, isolators, In-Home Displays and electrical safety. Some of them may have been trained to deal with three-phase supplies and asbestos-containing materials. They don’t necessarily know much about domestic wiring or consumer units or four-pole switches or any other electrical equipment in your house.
       
  2. We haven’t yet found out just where the fault with your hot water tank lies, but so far we’ve seen no evidence that it lies with the meter. Telling us whether your storage heaters are working properly would really help to sort this out. 
      
    If - as seems quite likely at this stage - the fault is downstream of the meter (e.g. in the consumer unit, the house wiring, the immersion heater controls or the heating element itself), an OVO engineer won’t be able to help at all. Fixing that sort of fault requires a competent electrician (not one who thinks that OVO could turn off an RTS signal that switches your immersion heater on).  Electricians, even competent ones, don’t necessarily know anything much about smart electricity meters.

You could save yourself a lot of anguish and frustration - not to mention money - just by providing answers to the questions I’ve put to you:

  • What are the offpeak hours promised by the tariff you’re on?
  • Are your storage heaters working as expected - charging up during offpeak hours and delivering heat when you want it during the day? 
  • The last two of the photos you’ve shared aren’t clear enough for us to see just what’s on the display; the labels are obscured, and it looks like the display wasn’t lit up when you took them. You only have to touch the blue button to turn on the lights. 
      
    I forgot to ask you to note the precise time you took the photos. The display changes as the meter switches from peak to offpeak, so there are clues to be seen there.

Please don’t stop now - we’re getting closer all the time.

 


Chris_OVO
Community Manager
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  • Community Manager
  • March 6, 2026

Hey ​@Jameses,

 

I'm really sorry to hear about the troubles you've been having with your immersion heater. It's wonderful to see that Firedog has been so engaged and helpful with advice and support!

 

I just want to reiterate a few things that Firedog mentioned, as I'm concerned that you might be counting on our engineer coming out on March 25th to sort everything out. If the issue is downstream or away from your meter, our engineers might not be the best fit for that problem, and they won’t have the necessary tools or resources to assist. If you could take some time to work with us, Firedog is already on top of troubleshooting and asking key questions. This will help us figure out where the fault might be, and we'll be able to guide you to the best support to get everything resolved properly and help you feel more confident again.

 

I completely understand how frustrating this must be for you, but rest assured we’re here to support you every step of the way. Just take it one step at a time, and together, we’ll get everything sorted out and back on track!


  • Author
  • Rank 2
  • March 6, 2026

Yes, my hunch (and my logic) disposes me to the view that matters will not be resolved or resolvable by an OVO or other smart meter Checker doing their check on 25th March. (I'll probably cancel that well before then).

From memory, the information requested... 

* The Off-peak time is 11:30pm till 7 :30am

* I can't get clear photos of the smart meter readings but if you can make any sense of the attached photos - I snapped then this morning about 10 am -??? 

This one is Day Rate I presume... 

 


  • Author
  • Rank 2
  • March 6, 2026

 


  • Author
  • Rank 2
  • March 6, 2026

 


  • Author
  • Rank 2
  • March 6, 2026

This is the best I can do... make what you will.... time for a long walk for me for the rest of the day!

Top row - these three photos... 

 


  • Author
  • Rank 2
  • March 6, 2026

And two photos of the lower fuse box arrangement. 


  • Author
  • Rank 2
  • March 6, 2026

And for anyone who can untangle the saga a lovely photo of cables that make as much sense as spaghetti junction. 

I must leave it there for today...busy now ...