Domestic heating All aspects of plumbing questions and answers, help, tips and information

[JIM CAROLAN]

I have an indirect central heating system,I drained the system last summer to repair a radiator. On recommissioning the system I have lukewarm hot water in all taps and no heat in one radiator. I vented the radiator and it has no effect,if the primary circuit contains air how do I vent it?

[plumbbob]

Generally airlock associated with single radiators can be cleared by simply manually turning off all the other rads and switching to CH only on the timer (unless you have a combi). The increase in pressure will force the air into the rad.

There ought to be a bleed valve in the pipework near the top cylinder coil. If this does not expel the air, the only solution may be to crack open a nearby joint to allow the air to escape.