Hot water switch

[Liz65]

With a combi boiler, if the heating is on, is it necessary to have the hot water switch on, or is that only needed when the heating is switched off? Many thanks.

[Jugglering]

With a combi boiler, you get a combination of heating and hot water, according to the settings you choose - these are usually (but not always):-

Heating - on 24 hours
Heating - on once (ie between 9am and 5pm)
Heating - on twice (ie between 7am and 9pm and then again between 6pm and 10pm)
Heating - off

Hot Water can be on demand (like it is on my combi boiler) or when the heating is on - on some boilers you can have the boiler heat a tankful of water which is stored in an immersion tank or other lagged container to keep it warm, on any of those settings. I don't have an immersion tank as my boiler is *on demand* ~ I can have bath after bath after bath ~ the water is heated up as I need it.

It all depends on which *combi* boiler you have !

[Liz65]

Thanks Jugglering, I have an oil-fired Worcester Greenstar external boiler. There are no internal tanks. The heating is on 24hours and we control it with the wall thermostat (the house is open-plan).

[gucciman]

are you sure its a combi boiler and not a system boiler? you have no tanks or a cylinder anywhere?

if its a conventional combi with NO sort of additional hot water storeage cylinder anywhere then hot water always takes priority over heating i.e. if you have the central heating on and you open a hot water tap then the heating will go off and the boiler will heat the water instead, when you close the hot tap the boiler will go back to the heating (usually after a 3 minute delay )

[Liz65]

Thanks gucciman,
According to the 'blurb', it's a condensing combi boiler and there are absolutely no tanks or cylinders, but you have answered my question, and I now realise that the I only need to use the hot water switch when the heating is off. However, is that still applicable when the thermostat is turned down - does that mean the water will be cooler or does it heat up to the normal temperature, about 60deg, Ithink?

[gucciman]

hi liz

if the boiler has 2 seperate thermostats, one for the water and one for the heating and you turn the water one down to a lower setting then yes it will lower the temperature of the hot water.
the other way of controlling the temperature of the hot water is to either slow down or speed up the hot water tap i.e. the faster you run the tap the cooler the water will be