Radiators not coming on - help!

[max58]

Hi. We have had some radiators fitted in an extension. Since then the new radiators heat up brilliantly but the pre-existing radiators throughout the rest of the house don't. The combi boiler is working fine with good pressure and the wall thermostat is kept at its highest to try to encourage the radiators to spring into action. We are now into our 4th day of no heat and we are cold! It's been suggested that there is a blockage somewhere and we should just wait for the water pressure to force it out. It's also been suggested there is nothing else we can do and we should just wait it out. Is this right, as we could presumably be without heat for weeks? Oddly the heating seems to come on at about midday for a very short time and then goes off again until 24 hours later. This seems to coincide with the plumber arriving and so it looks until it's working until he leaves, when it goes off and we're without heat again. Any suggestions very gladly received. Many thanks.

 

[jtsplumbing]

1st are you sure that its a combi boiler that you have, from what your describing it sounds like there is a zone valve on the system closing part of the system, have you had any of the controls replaced ? do you have an extra room stat controlling the new radiators ?

 

[zzzjim]

Does sound like you need someone who understands the controls
( and the bigger bill if they are turned up ) If new rads are turned down do others spring into life ?

 

[REDSAW]

i guess the combi sits close to new rads?
the new rads are sapping all heat and returning to boiler making a circuit!.
could also be an air lock on primary to old rads.

knock theese new rads off, the see if old rads heat up.
if they do, turn one new rad on to minimal then repeat for others. see what u get.