My Heatrae Sadia Electrolux is not heating water at night - help!

[Kelly Thompson]

My central heating is working fine and if I demand water, then I get a small supply of hot water within an hour. The problem is my water does not heat up over night on the peak rate as it should do, so I do not have hot water unless I use the demand button. There is no alarm sign and all seems to be working fine apart from this. The pressure is at 1.5-2 (I recently reset the pressure, hoping this may help). Can anybody suggest what the problem may be?

 

[SparkyChick]

It would be immensely helpful for members if you could include the model number of the unit.

 

[brianmoooore]

Google doesn't recognise "Heatrae Sadia Electrolux", but there is a range of Heatrae Sadia Electromax boilers, which I suspect this is. They are an electric boiler, combined with a fairly conventional hot water cylinder, which has an immersion heater at the bottom and a boost immersion heater part way up.
If the water isn't heating up overnight, then either the off peak supply is not reaching the lower immersion heater, or the immersion heater is faulty. First job is to test to determine which.
The immersion heater contains a thermostat to set the hot water temperature, and a second thermostat set at 90 or so degrees, which acts as a safety cut out, if the first thermostat fails on. The second thermostat is resettable by a small button, and may be the immediate problem, but that then raises the question as to why it tripped.

 

[Alan-N]

Heatrae Sadia Electromax has 3 (count them) supplies, 2 for immersion heaters top (boost) and bottom (off peak), 1 for central heating side. any of the circuit breakers tripped ? and of course the thermostats have got thermal cutouts with reset buttons under the cover always worth checking with all the power off first

 

[Weronika]

I have the exact problem. Central heating working fine but water does not heat up over the night. Pressure is fine too. Have you resolved your problem and may I know why ? That could help a lot. Many thanks!

 

[Alan-N]

I have the exact problem. Central heating working fine but water does not heat up over the night. Pressure is fine too. Have you resolved your problem and may I know why ? That could help a lot. Many thanks!

If it only normally heats overnight, then you either have an off peak circuit supply to the lower immersion heater or an external timer (faulty timers can often be the cause). Have an electrician check that supply from consumer unit, should be on a 16A breaker to immersion heater and also check if the thermostat reset button needs to be reset. If it's the reset button it might work fine after that, if it trips again the thermostat is allowing the tank to overheat and needs to be replaced. IF there is power to the immersion heater and the thermostat has not tripped or has no reset button, then one or the other is faulty, an electrician can quickly establish if it's the thermostat and it's a fairly simple repair, the heater itself is a bigger job and needs the tank drained to replace the heater

 

[brianmoooore]

The reset button on many immersion heaters lies between two live terminals when the power is on, so make doubly sure that the power is off.
I have had more than one customer of mine find out this the hard way.

 

[Sparkingmad]

Central heating works off an Amptec c600 boiler which is totally independent to the hot water. My advice without looking but after many years of working with these units is it is most definitely the stat has burnt out. If you press the boost button on the front do you get hot water after about 1 hour?

 

[Weronika]

Central heating works off an Amptec c600 boiler which is totally independent to the hot water. My advice without looking but after many years of working with these units is it is most definitely the stat has burnt out. If you press the boost button on the front do you get hot water after about 1 hour?

Yes, last time it took around 45mins and had hot water only for couple minutes.

 

[Alan-N]

Yes, last time it took around 45mins and had hot water only for couple minutes.

The boost only operates the top immersion heater, but it clearly works, it would take a few hours to heat up a tank from cold, your issue is the bottom immersion heater, and it needs to be checked as stated above, it's a simple test and should identify if it's the thermostat or heater in minutes