Combi Boiler pressure gauge reading 0, and radiator half on!
The first thing you need to do is to put some more water into your heating system. This is usually done by allowing water from your (pressurised) domestic cold water supply to flow into the system: On older boilers, this is done with a connection (often made with a removable hose) on the pipework just outside the boiler. Newer boilers may have a built-in connection with some sort of removable link (sometimes looks like a plastic key).
Once you've got the boiler up to working pressure (typically about 1 bar - 15 psi), you should be able to bleed your upstairs radiator properly.
This may be all it takes, though the pressure excursions you're getting when you run the hot tap suggest there may be another problem. See what happens to the pressure as the boiler heats up and cools down. There really ought to be very little pressure difference between the two conditions. If you see significant changes, this usually means that the "pressure vessel" (or in hydraulic terms, system accumulaor) has lost its air charge.
The pressure vessel is a metal container inside the boiler, usually painted in red enamel. Somewhere near the top, you will find a schrader valve (like the one on a car tyre), and you can use this along with a tyre pump to replenish the air in the top of the vessel. This will reduce your pressure transients for a while, but you need to keep an eye on it. If the problem returns, you probably need to replace the pressure vessel (or clag another one into the plumbing alongside the boiler).
Feb 03, 2009 |
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