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Boiler problem - advice required

Postby colbyd » Tue Oct 28, 2008 5:18 pm


Have a Worcester Greenstar 40 cdi and having a few probs, wondered if someone could help me out as it has just gotten a bit chilly and we have next to no heating or hot water!

The controls seem to be working fine, heating and water come on as programmed, water pump is running, no unusual sounds from pipework and pressure at the expansion vessel is a constant 1.5 bar.

There are 3 motorised valves on the system controlling upstairs rads, downstairs rads and the unvented HW tank.

Problem I have is that the boiler comes on, ramps quickly up to set temperature and then shuts off and cools down, then constantly cycles like this when there is demand for heating/water. The return pipework from water pump is lukewarm at best.

I added a towel rail to the upstairs bathroom and think this may have intorduced an airlock - does this match up with the symptoms?

If so, what's the best way of removing the airlock? The only drain point I can find is on the return pipework in the boiler itself.
Do I drain the system of a gallon or so from the boiler?

Many Thanks for any assitance from a cold Edinburgh
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