Adding new zone to existing CH system query??

[glowboy77]

Howdy,

Just a query at present, i want to know if i can add (not personally of course) a seperate zone to my CH system. It would be great if i could control the new extension without having to have heating on everywhere else in house.

My boiler is downstairs, with the pump, 2 x 2 port valves, cylinder, expansion tank etc on first floor landing in airing cupboard. The part of the house i would like to be on a different zone is directly to the side of the utility (boiler site), is it possible to just T off the flow and return immediately from boiler to feed rads in new extension and using a valve and seperate thermostat just heat this part without heating rest of house??

Or, would i need seperate pump also as pump is on first floor??

Any info much appreciated,

 

[stem]

Yes, it can be done.

How easy it is to do it depends upon the layout of your existing pipe system. The professional you engage to do the work will be able to advise you better after inspecting the existing set up.

Reading your post I can't tell if the extension and / or radiators are already existing or future. So, my answer assumes that there are no radiators existing in the extension and is based on my understanding of the information available.

A 'branch' pipe feeding the new radiators can be taken from the existing flow pipe, but it must be somewhere after the pump, but before the existing central heating motorised valve. A new motorised valve can be inserted in this new 'branch' feeding the extension.

Care will be needed regarding the connection of the return pipe to avoid "reverse circulation" (This is difficult to explain in a few words. Do a search if you're not sure what it is.)

You will also need to consider how you will control the new motorised valve. A room thermostat will need to be located in a suitable area (eg if the extension contains several rooms which include a kitchen, the kitchen is not a suitable location as when cooking, all of the extension radiators would go off).

Also, if you want to operate the extension heating at a separate time to the rest of the heating, a new programmer / timeswitch will also be required, although this can be an integral part of the thermostat. The motorised valve also contains a microswitch that will operate the boiler & pump when the extension requires heat. This will need wiring into the boiler control circuit.