DIY Doctor UK DIY Forums

I have fitted a Timeguard NTT04 GP Timer to my immersion tank. I have also fitted a fused isolation switch. The timer works fine but the 'on' switch seems to come on outside of the programmed on -off times. I think the thermostat is over-riding the timer ?
Can I disconnect the thermostat and wire the timer direct to the element

NO! you can NOT disconnect the immersion heater thermostat, if you did you could boil all the water, that would not be good.

You have either wired the timer the wrong way round or set the programming wrong, the thermostat is a safety device.

Thanks. I'll re-check the programming !

This http://news.bbc.co.uk/1/hi/england/somerset/7179092.stm is the result of a thermostat failing, clearly should never be removed, it is a safety item.

I have used time to reduce water temperature, the problem is we want 60 degs C at least once a week to stop legionnaires, but being cooler loses less energy, so I have my boiler switch on 4 times a week, three for half hour and one for an hour, and half hour will give us warm water at taps for washing hands, during the summer, winter DHW same temp as CH.

In the main the thermostat works better than a timer, if I had a tank thermostat I would use it, but there are no cables, and there is still a thermostat in the boiler, but using that it keeps the pipes warm so wastes energy.

It takes 4 days with no DHW heating before the tank cools, so even if you do turn off with a timer, the cooling is so slow, you may not notice any drop in temperature.