combi boilers

[alan-r]

hello
is it the cold weather thats affecting my combi boiler(and mums)to run warm not hot water,does it depend on the incoming cold water temp,its not a high spec one but thought that it would compensate for the cold water input

[The Builder]

cold input does affect any instantaneous water heating Alan.
Maybe the combi is a little undersized...........try turning the hot water temp control on the boiler up

[gucciman]

a combi boiler is designed to raise the temperature of water a certain amount at a certain flow rate. lets say a typical combi will give a 35oC rise in temperature at around 9lts a minute flow rate. so in the summer if your incoming cold water is 20oC the boiler will heat it to 55oC, but in the winter if your incoming cold water is only 5oC then the boilers only going to heat it to 40oC

this is why it is very important when choosing a combi boiler you choose the most powerful one you can afford to give a decent supply of hot water.

the boiler cannot automatically compensate for the temp of the incoming mains cold water, all you can do is to turn the hot water thermostat up to max and turn down your hot water tap slightly so the water passes through the boiler slower and so picks up more heat.