Combi Boiler Basics

Joined
17 Jan 2010
Messages
115
Reaction score
2
Location
Bedfordshire
Country
United Kingdom
Hi,

I am just trying to understand how a combi boiler actually works inside.

Am i correct in thinking that the water that circulates within the heat exchanger and is used to heat DHW for the taps is the same water that is used for the central heating and pumped to the radiators? (similar to a conventional boiler with a hot water cylinder?).

If this is the case.....how is the central heating maintained when somebody is using the shower etc....My thinking is that if the heat exchanger is passing all of its heat to the shower, how is the water going to the rads maintained? Does the boiler flame intensity to compensate?

Thanks people
 
Sponsored Links
Joined
22 Jan 2007
Messages
6,783
Reaction score
1,213
Country
United Kingdom
The heating won't work when hot water is drawn. You won't normally notice this though.
 
Joined
2 Nov 2010
Messages
3,423
Reaction score
515
Location
Humberside
Country
United Kingdom
Central heating system is sealed and the combi boiler heats this.
Cold mains passes through a plate heat exchanger and when hot water is
called for the combi diverts the central heating water to the through
this plate heat exchanger. Hot water for the tap and central heating water
never meet.
If you download virtually any combi boiler manual there is a layout
diagram and you should be able to work out the operation from that.
 
Joined
26 Jun 2004
Messages
64,092
Reaction score
4,620
Location
London
Country
United Kingdom
The addition to the answer is that the rads have a long thermal time constant and you dont notice that they have cooled a bit during the 15-20 minutes that a shower is taken.

Tony
 
Sponsored Links
Sponsored Links
Top