Combi boiler and radiator question.

I'm installing a combi boiler with TRV's on all but one radiator as is required for safety reasons. I want the living room radiator controlled by a room stat so there will be no TRV on that radiator.

My question is, how do you size the radiators so that all the other rooms always reach the temperature set on their individual TRV's before the living room stat reaches its set temp and turns the whole system off?

I can only think that the other room radiators must all be overated so that they can always heat up their rooms before the living room gets to its temp or alternatively the flow to the living room radiator is restricted.

I feel I must be missing something and hope someone can put me right.

TIA

Steve

That is pretty much it.

You should size all of the radiators properly though, to make sure that you are providing adequate capacity for each room without going too far over the top.

Don't use the guesstimate methods that come in leaflets from DIY stores etc. - really this should be done properly by calculating the heat losses.

The radiator manufacturers have calculator programs for doing this where you basically measure each room and plug the numbers in. They account for heat loss through each surface and for air changes.

The program on the Barlo site is reasonable, as is the Myson one, although their site is under conctruction. I have a copy that I can email to you if you send me an email request.

Once you have selected and installed the radiators, you can balance the system according to the FAQ. Then for the living room one, simply reduce the flow at the lockshield valve so that the room takes a bit longer to come up to temperature.

If you follow the workings of a heat calculating program, the other radiators will be generously sized as well so you will get the effect tha tyou are looking for.

.andy

To email, substitute .nospam with .gl