What do to with an immersion switch? Electric water heating question!

nicegirl

We have just moved into a property which heats water using electricity. I’ve never lived anywhere with this and our letting agent helpfully couldn’t tell us anything about how to use it! I’m hoping that a wise MSE-er might be able to help please!

The immersion heater tank has a Horstmann Electronic 7 Water Heater Controller which heats the water during the night when it’s cheaper so we have hot water to use during the day.

The immersion heater is in a cupboard in the bathroom. Outside of the bathroom, on the wall there are two switches that look like light switches which say ‘IMM’. I worked out over the weekend that the Electronic 7 does not come on unless the right hand IMM switch is turned on. My questions are:

Do I need to leave the IMM switch on at all times or just at night when the Electronic 7 is working? My partner turned it off before he went to work yesterday morning and the tank was still full of hot water when we got in, so presumably it doesn’t affect the water staying hot if it’s in the off position? If the switch is left ‘on’ all the time, is it still using power even if the Electronic 7 is not running?

What could the other IMM switch be for? The hot water comes out of the shower, and kitchen and bathroom taps fine using just the one switch. We have electric panel heaters so it can’t be the heating. Could it be for the washing machine?

Thank you!

lstar337

Do you have two fuse boxes?

If you do, then it would be best to leave the overnight switch on, as it will be controlled by the E7 timer.

Do not leave the other switch on, this is for a peak-rate top up only!

colourblind

It sounds like a similar system we had in our old house. We had economy 7 water and heating. In our airing cupboard we also had 2 switches for the immersion heater. We left the economy 7 switch permanently on. We would only use the other switch if we used up all the hot water during the day and needed more water before the economy 7 kicked in at 12 midnight. You have two elements in the immersion heater one for Economy 7 and one for normal usage. If we ran out of water and switched on the non economy 7 element, we always turned it off after a while. We also had Dimplex heating on economy 7, never switched them off other than during the summer months.


Hope it helps

nicegirl

Thank you both!

We just have one fuse box. So you think that the switch I've been using is the Economy 7 switch and the other is a normal immersion heater?

The Electronic & has a 'boost' function, so even if we ran out of hot water I'm guessing we'd just use that, meaning I'd never need to switch the other one on?

lstar337

If you only have a single fuse box then your E7 may not be switched at the meter. IF that is the case you need to make sure there is a timer for the E7 supply and that is set to come on at the correct times.

Any chance you could post a picture of your meter and fusebox, hopefully showing the cables?

nicegirl

Not switched on at the electricity meter you mean, or the Electronic 7? The Electronic 7 is definitely coming on only at night.

lstar337

nicegirl wrote: »

Not switched on at the electricity meter you mean, or the Electronic 7? The Electronic 7 is definitely coming on only at night.

Sorry, should have been clearer. There are quite a few E7 set-ups out there and I was trying to pinpoint which you have.

What I consider to be the best set-up is a single meter which has an internal time or radio switch which enables a second E7 fuse box during E7 hours. This is good because it means the end user has nothing to do, at all.

If you have to start using your own timers it becomes complicated because you have to know what your E7 times are (they are not all the same) and you have to program the timers yourself and sometimes compensate for daylight savings.

A piccy of the meter/fuse box should make it easy to determine, but it could be identified through questions.

Is your meter digital, or does it have a spinning disc?
Do you have a big mechanical clock beside your meter?
How many cables go in/out of the meter?
Does your single fuse box have two distinct sections?
Do you have electric storage heaters?

See why a piccy is easier?:D:D

nicegirl

I see!

The electricity meter has a spinning disc. It doesn't have a clock. I'd have to check on the cable situation! I'm just at work at the moment.

The fuse box seems to just be one long section and no we do not have electric storage heaters.

lstar337

Are you sure you are on an E7 tariff?
Does the meter have two registers?

If you don't have storage heaters, what heats your space?

nicegirl

Yes it has a low and a normal register with a spinning disk underneath.

I don't know if I'm on an E7 tariff, it was another poster who suggested that. The immersion tank is connected to a Horstmann Electronic 7 Water Heater Controller. This makes it come on during the night to heat the water.

It's a new build flat and has wall mounted electric panel heaters in all the rooms.

lstar337

Panel heaters? Oh dear.

If you are on E7, you probably shouldn't be.

E7 carries an inflated day rate to compensate for cheaper energy overnight. If you are on E7 (I guess you are if your meter has two registers) then you might be getting cheap hot water, but unless this flat is super insulated you'll be paying over the odds for your space heating!

This is in a new build?

Strange for a new build to have such a stupid set-up, and strange to be fitted with an old mechanical meter. !!!!!! were they thinking?

If you have any cash of your own, you should start looking at installing some storage heaters.

Here are the instructions for your timer btw: http://www.horstmann.co.uk/files/7813/9867/2126/user_guide_Electronic7_series_3.pdf