Gas Condenser boilers: Turning the power off when out and during the night

Charlie_H

Hi All,

I have a gas condenser bolier (Baxi HE 80 plus) and have noticed that it fires up randomly when not in use. After doing some research, have concluded it does this to pre-heat the heat exchanger to provide instant water in case I want to use it. This uses electricity and gas and I've wondered whether I can disable this as I'm out during the day and don't need it during the night when asleep. I live alone and not fussed about having hot water available at the turn of a tap. I've looked in my manual to see if there is a way to disable this function but nothing noted and assume the only way to do this is turn the power off at wall socket. I also found this link. http://www.imeasure.org.uk/carbontalk/index.php?topic=76.0.

Has anybody either considered this? Or know of any reason why it would be bad practice to turn my boiler power off for long periods of time.

Thanks
Charlie

penrhyn

If you are not happy with the preheat function operating, why don't you switch it off.

There is a knob for this on the control panel under the front flap of the boiler.
http://www.baxi.co.uk/docs/Baxi_Combi_Instant_HE_Installation_and_Servicing_Instructions.pdf

See page 7 section 3.2, apologies if its not the right boiler.

Charlie_H

Thanks for your post with suggestion but had already checked manual and the knob you describe to switch off is for 105E not 80E. Decided to switch off at wall
Charlie

jim22

My worcester bosch junior greenstar does the same even when set on eco mode.

CRH71

The boiler in my last house did that, too. There was a combination of buttons that had to be pressed to disable the function but I never discovered what the combination was until I managed to download the repair manual for it one day by mistake that gave the guidance!
Nothing mentioned in the user manual at all.

To be quite honest, though, it didn't cost a lot in gas with this feature on - it would only fire up for about 5-10 minutes and even then only once every 6 hours. I used to have a card meter at that place and my "summer" gas bill was around £7 a week for purely hot water from this boiler. It will probably cost you more money to turn this feature off, as the boiler holds around 10 litres of water in this state and 10 litres of water will take a fair bit of initial heating.

Gestuper

The rate at which a a tank of water looses energy is proportional to the temperature difference between the tank and its suroundings. That is the hotter the tank, the fastern it looses heat.

The amount of energy necessary to reheat the tank is equal to the enegy it lost on cooling.

Hence if hot water is not required for a time it is better to let it get cold and reheat it once, than to reheat at reguar intervals and thereby maintain a high rate of heat loss.

IMPORTANT The heat exchanger in a boiler with a short flue is in better thermal contact with the outside than the ninterior of the house. It is important not to turn the boiler off when it is below freezing outside. If the boiler gets cold it first tries just turning on the pump (effectively improving contact with thr inside of the house) and if that is not enough it turns on the gas.

That said, on my Glowworm my pump sometimes comes, on for no apparant reason, or runs on for a long time after heating.

That said my Glowworm boiler