combi boiler

[Pedro22]

how does a combi boiler separate domestic hot tap water from central heating water?

[clever trev]

The same water circulates in your heating syterm (ie) the water in your radiators gets pumped round back to your boiler for re-heating. your hot water is a different circuit, cold water is fed into your boiler to be heated only when you turn on your hot tap. Ok. I think

[almcd007]

In addition to Clever Trev, You have a loop, that's fed from the cold water filler for the heating system which is under pressure and it's just that - a loop, the water gets pumped around and around. There is also a cold water feed to the boiler for water which gets distributed after heating via the hot water pipes to the taps.

A pressure switch then "knows" when you turn a tap on and it kicks the boiler in to heat it up.