Daft question about combi boilers?

[shaun127]

Wife just asked me something and I dont know the correct answer,

So where else better to ask than the wealth of knowledge that is DW.
Oil combi boiler is currently on heating the water in the rads in the house. Wife wants to go in Bath so she presses the button to heat the water for her bath.

Does she need to do that, or will the water that has already been heated, and the water that is continuing to be heated for the rads now fill the bath instead.Once the bath is full any extra hot water will continue heating the rads. We have no extra hotwater tank. in the house

 

[IANB]

No lol the rads is a sealed loop of water plus additives. When you call for hot water the mains water is passed through a heat exchanger in the boiler heating the fresh water. The boiler uses a diverter valve to facilitate this

 

[chookey]

She could not press the button and start running the bath. She will know quite quickly whether she needed to or not.

 

[shaun127]

Told ya it was a daft question. LOL perhaps I didnt explain it well. but I didnt mean that the water in the rads would fill the bath.FFS it would be stinking and brown sludge. I meant the water already been heated for the rads and lying in the tank in the boiler before its fed to the rads would heat the bath without pressing the "hot water button"?

 

[shaun127]

Diverter valve, would it divert hot water automatically if the hotwater tap is run even with the boiler being set to heat hot water is what im asking if the boiler is heating water for rads anyway

 

[IANB]

It will heat one or the other. Only one circuit is run through the heat exchanger at a time. There is no storage tank as such

 

[shaun127]

All boilers no storage tanks? i thought mine had a small tank in bottom
@IANB mines is an outside massive woucester boiler

 

[IANB]

AFAIK Combis just have an expansion tank.
One of the plumbers might give more info mate ie @JimmyP or @wiz569

 

[wiz569]

Combi's dont have a storage tank for hot water,its an on demand system if you like, heating system is separate in them there is no cross over between heat and hot water.

 

[shaun127]

Cheers Lads