Central heating water temp

[wwwebber]

Hi,

I have a non condensing gas boiler, what is the best temp to set the boiler on for the central heating water temp ? - currently got it set on 65c but this is low according some things I have read.

Please let me know what you think. Cheers.

 

[oldbuffer]

If it really is a non-condensing boiler (not the same as non-combi) then the heating system will likely have been sized for an 11 degree temperature drop between flow and return and radiators sized for a 50 degree difference between ambient temperature and mean water temperature. Assuming 20 degrees ambient, plus 50 degrees = 70 degrees plus 5 degrees (roughly 11 /2) - 75 degrees. Allowing for losses in the pipework, flow temperature from the boiler should be about 78 to 80 degrees.
If you are running at 65, it will take a good bit longer to heat up.
If your boiler were condensing, the aim is to get the return temperature of the water at the boiler down to 55 degrees or below, to allow the boiler to operate in condensing mode. Under these circumstances, flow should be around 75 degrees, as the flow / return differential should be about 20 degrees. The radiators would have to be bigger to allow for the reduced heat transfer.