How to control an immersion heater (Ed.)

[zakinho]

I need to control my water heating for the short term. I have a tank with an immersion heater that does not have a thermostat and runs 24/7 with the hot water at 75C . The heater is a dual element, each with it's own fused spur. Can I initially swap the fused spurs with these timers which will enable me to at least have it run for just a couple of hours per day?

https://www.screwfix.com/p/lap-digital-immersion-timer/1804r

Further to that, can I add in this strap on stat into the mix so that I can also keep the water at 60C ?

https://www.screwfix.com/p/drayton-hts3-cylinder-stat/95630

If this is possible what should the wiring configuration be?

 

[flameport]

I have a tank with an immersion heater that does not have a thermostat

All immersion heaters have thermostats, including that one. It's located under the black cover.
If there was no thermostat, it would literally boil the water into steam and be exceptionally dangerous.

The cylinder thermostat is NOT suitable for an immersion heater as it is only rated for 3 amps - far less than the 13+ amps that the immersion heater uses.

The timer could be installed, but in addition to the existing fused connection unit, not as a replacement for it.

 

[zakinho]

All immersion heaters have thermostats, including that one. It's located under the black cover.
If there was no thermostat, it would literally boil the water into steam and be exceptionally dangerous.

The cylinder thermostat is NOT suitable for an immersion heater as it is only rated for 3 amps - far less than the 13+ amps that the immersion heater uses.

The timer could be installed, but in addition to the existing fused connection unit, not as a replacement for it.

Thanks for the reply.... I was advised the same but there is no stat that I can see under that cover. I missed the 3A rating for the stat I was looking at.

 

[Harry Bloomfield]

I was advised the same but there is no stat that I can see under that cover.

Then you failed to see it, it absolutely MUST be there, no exceptions. Your electric bill, would be horrendous, were it no there.

 

[ericmark]

There are immersion heater timers designed for the job. Some have fuses built in, some can take duel supplies, the one I have does not run all the time at 3 kW designed for twin elements

although at around £300 this one is not designed for normal use, but for when one has solar panels. And I now realise was not really worth the money. However there are all sorts you can use.

That cylinder looks small, I would think it may just about fill a bath if you are adding cold, there are valves to mix hot and cold

you can't store hot under 60ºC and stop legionnaires and 60ºC is still too hot to put hands under it, so the mixer valve allows safe temp at taps and no legionnaires, and the water can be stored hot enough to fill a bath.

I from 2019 to 2023 when solar panels fitted, tried to heat my DHW using just time. I was told, which I found was incorrect, that to heat DHW with electric was more expensive to using the central heating, so I set in summer the boiler to run 4 times a week for ½ hour each time with a 20 kW boiler, when I moved to electric it told me how much I have saved, in other words how much used, typically 2.5 kWh per week, so it would seem turning on ½ a day would likely give you water at hand wash temperature, but you will not know it that is safe, and if you have the option of using the immersion heaters built in thermostat why take the risk.