Using cheap rate electricity on an immersion heater

[GB]

Using cheap rate electricity on an immersion heater - you have two immersions, one does just the top of the tank for topping up with expensive electricity, and the other does the whole tank for use with cheap electricity. What am I looking for in terms of a time clock that will switch between the two? Assume the electricity supply is only sufficient to run one immersion heater or the other - not both at the same time.

[Owain]

one supply to bottom heater on timer or to top heater on boost setting.

Owain

[Skipweasel]

I thought cheap-rate electricity came through the same circuit as everything else, you just set the timer so it's on the lower-rate meter. Two meters (or one modern one capable of dual-rating) but one circuit.

That's not to say you couldn't have two circuits, one for low-rate so you could run things off it and have a central timer - just that it's not done like that in most cases.

Anyway - one immersion heater, one circuit, different rates according to what time of day you switch it on, is what I'd expect.

[Dave Liquorice]

An immersion heater timer capable of running two heaters? This might be identifyable by having a "boost" button. One thing with a seperate timer one would have to make sure the whole tank heater was only timed to come on during the off peak period, keeping the off peak clock and the immersion timer clock in sync is vital...

I'd rather wire two supplies one from the network switched off peak supply for the whole tank heater and the other from the normal supply for the boost heater.

[John Rumm]

Yup they have that, however some also have a separate CU energised via the time switch, so that you can have circuits that are only powered during the cheap rate period. You can see and example of a setup liek that here:

That's not to say you couldn't have two circuits, one for low-rate so

These days, no not so often. More common in places with storage heaters.

[GB]

Thanks very much - looks just the thing.