Dual Immersion Heaters

chrish99

Hi,

I just moved into a new 2 bedroom apartment and i think we have a hot water storage tank fitted. Attached to this, there are 2 immersion heaters, one at the bottom and one near the top.

From looking at our electricity meter, we have a rate 1 and rate 2 clocks (rate 2 operating from 00:00 until 07:00am)

Speaking to a few people, there seems to be a consensus that one of them will run at night and one can be used anytime if more hot water is needed... but i have no idea which is which?

Last night (at 10pm), i left the bottom immersion heater turned on.. and in the morning, the reading on rate 1 on the electricity meter went up by 5 units (compared to rate 2 which only went up by 0.5 units). THis would suggest that something was still using rate 1 during the night?

Does anyone know which immersion heater is likely to be which or what the best setup would be. we only really need hot water on the morning and maybe at night, thou we use a dish washer mainly which might heat its own water (im not sure yet).

thanks for any help (and maybe saving me a fortune)

Chris

Cardew

The normal situation when you have 2 immersion heaters is that the bottom one heats the whole tank and the upper one just heats a little water.

You would normally use the top one if you only used a little water in the morning - say for a shave(assuming Chris denotes the male of the species!!) or to top up during the day if you ran out of hot water.

It depends on the way they are wired, but it is pretty certain that the bottom one will only be wired to come on during the Economy 7(rate 2) period. i.e. if you leave this switched on 24/7 it will only switch on at midnight. This is easily checked by switching it on during the day and watching your meter - it shouldn't move.

Assuming that your Hot water tank is modern and well lagged, you will use suprisingly little heat from the tank in 24 hours(and in the winter that heat is not wasted as it heats the house) so you are better using electricity at rate 2 prices.

It really is a case of experimenting to see what meets your needs.

Nearly all dishwashers(and most washing machines these days) are 'cold fill' only so heat their own water. It will therefore be best to have them on timers to operete during rate 2 timings.

However as you are in an apartment you need to be aware of a potential noise problem - pipes gurgling and washing machines spinning. Some blocks ban their use at night.