E7 with 2 meters (on/off peak), but current only goes through one?

Hi folks,

We moved into a new flat about 6 months ago and have realised we're being billed for all of our electricity at the expensive "all day" rate - despite having a very large "Thermaflow" electric boiler which is designed to draw tons of power heating up water overnight to use throughout the day.

The flat has an interesting wiring setup for Economy 7 which I hadn't seen before - there are two meters (one "off-peak" / cheaper rate, one "all day" more expensive rate) and a Horstmann radio teleswitch which I believe is supposed to control the usage of the lower rate electricity.

Of the two meters, the "off-peak" one hasn't moved at all since we moved in - clearly everything is going through the all day meter.

I tried to go the sensible route to get this resolved via our supplier, but I've called them a few times and they don't seem to know anything about the teleswitch and don't seem to understand the problem at all.

Pictorial wiring diagram:
drive.google.com/file/d/1fSfQ0KYlqdu55YvD941YPKE2K0KoGAVa/view
Photo:
drive.google.com/file/d/1SvlaB1YaVGVI-cbTcr4wbCMoLfYM7Www/view

My understanding of it based on googling lots and reading is that the teleswitch (controlled by AM radio signals) is supposed to turn on and off during the night - essentially opening or closing the chunky 80A mechanical relay to allow current to flow during the off-peak times.

From my testing with the multimeter it seems like this relay is permanently closed in our teleswitch, yet no current is actually going through the off-peak meter.

I don't really understand the way this is wired up - from what I can tell it looks like all of the load (consumer unit + boiler) goes through the single Wylex main switch, which is connected directly to the live load output on both meters! As such, I don't see what would control which meter the current would flow through - I'd actually almost expect it to be split between the two, though I guess a minor variation in resistance between the two paths could cause it to pick one vs. the other.

If anybody can help me understand how it's supposed to work, and what's actually happening just now, that would be greatly appreciated!

Thanks!

 Teleswitches   used to be switched by a signal transmitted by Radio 4  I believe .   I 'm wondering if that tariff  was  withdrawn at some time , leaving you to inherit  top rate only .  

Your power supplier should be getting the metering company round to sort it out .

Who are  do you pay your bills to ?  

Faulty  Teleswitch not switching    or no signal at midnight ?   :C  

I doubt if you can tell the status of the tele-switch with a multi-meter (without disconnecting it). There will always be a circuit via.  the external wiring.

However I can't see how it would ever work if your schematic is correct as it seems to just put the two meters in parallel.

You need to come on stronger to your supply company. They have sold you a tarrif which they are not supplying.

OR

I'm wondering if your boiler feed should be in the other pole of that main isolator, Perhaps someone has moved it to get the boiler on in the day. Its not clear on the photo just how that is wired. That wouldn't give you low tarrif on the rest of the flat though.

Geoff1946 said:

I'm wondering if your boiler feed should be in the other pole of that main isolator, Perhaps someone has moved it to get the boiler on in the day. Its not clear on the photo just how that is wired. That wouldn't give you low tarrif on the rest of the flat though.

Click to expand...

+1   I am guessing the original set up was boiler only on at night time fed from E7 supply via one pole of isolator.  Then new boiler fitted, (that MK boiler CU looks quite new) and as no supply in daytime Mr boilerman & co can't test the new system as no power to it.  So Mr boilermans electrician joins it onto the perm feed off the daytime meter with that extra connector block below isolator switch.

First check I would do is to get the boiler mini CU feed put back into the second pole of the isolator, then see what happens over night to verify that tele-switch & second meter do actually work. If that doesn't work its back to your suppliers to report a fault on their kit. Once you have proved if the E7 meter etc is working, then you need to decide if your wanting E7 rates for all power consumed or happy with just the boiler and/or if you need power to the boiler during daytime. That will then be a second problem to fix.

Doc H.

Your wiring diagram does not make sense.

Where is the electric boiler connected, to the main day meter, or the off peak meter via the teleswitch?  the "Wylex main disconnector" appear to have off peak L and peak L into the top and only 1 out of the bottom, so it is connected to one or the other, which one?

That is not "economy 7" that is the old white meter system that preceded it. With the whit meter system, only the off peak circuits get billed at the low rate at night.  With E7 or E10 it all runs through a single dual rate meter and the whole house gets billed at the cheap rate at night.

The easiest way to sort out the issue is to "upgrade" to E7 or E10 and all the metering will be replaced with one new dual rate meter with the teleswitch built in.

That type of storage boiler cannot store enough to heat a whole house just on E7 so I suspect it has been connected to the direct supply as the only way it will work.

For that sort of heater, I would have it on an E10 supply. That gives 10 hours of cheap rate, but not all in one go overnight, you get an early morning, mid afternoon, and late eveninig off peak period, so the storage boiler does not have to store it's heat for so long.