Economy 7 immersion heater timer

Hi,

My house is currently on economy 7 as we are fully electric. Our immersion heater has 2 switched one for day rate and one for night rate.

Our electricity bill has been sky high and we have narrowed it down to the immersion heater being heated for the full time when E7 switches on for the full 7 hours. is it possible to install a timer so it only comes on for 2 hours in the morning, or will it reset the timer if I wire it into the E7 circuit.

Thanks

the stat should ensure that the heater only works intermittently as the water cools. how well is the tank lagged? my estimate is should cost about £2 /night.

telectrix said:

the stat should ensure that the heater only works intermittently as the water cools. how well is the tank lagged? my estimate is should cost about £2 /night.

Click to expand...

This is what we have got

what's the kW rating? should be on the element cover label.

my earlier post assumed 3kW so about £2/night tops. based on E7 rate of about 3p/kWh.

plus that looks like a part l compliant unvented cylnder so as telectrix said the stat should cut in and out, is the hot water hotter than 65 degrees, if it is you could have a faulty stat

The norm is to exceed 65°C to avoid legionnaires, at least at some point in the cycle, and with off peak either a manual boost or twin thermostats (some times twin immersion heaters) so whole tank heated over night, with off peak, but should it have heavy demand then upper thermostat/immersion heater will heat a small amount of hot water to keep it going until the next off peak supply.

Some times an attempt to reduce the bill by turning down the temperature can do the reverse, if lower immersion heater is turned down, then upper one more likely to operate, the same if lower immersion becomes faulty. Idea is the water will never be cool enough for upper thermostat to operate.

With a top entry immersion you can get two immersion heaters in one, but side entry needs two immersion heaters. You only show one, so would seem some thing missing?