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No water in top radiators

Postby jenkeith » Mon Dec 08, 2008 9:24 am

Never had this before, no water in upstairs radiators & when I bleed them it sucks air in!. I suspect this may also have damaged the pump. Why would this happen?
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Postby plumbbob » Mon Dec 08, 2008 11:42 pm

I assume the header tank is at a low level which means the pressure is too low to fill the rads - a common problem.

If the pump is fitted in the return side of the system, and the rad valves are screwed down, it is possible the pump may suck water away from the rads resulting in the situation you describe.

Turn the pump off and bleed. What happens?

If that doesn't work a neat trick is to firstly work out which end of the rad is the feed (gets hot first). The turn off the return end valve and open fully the feed end - then bleed again. The pump should then be forcing water into the rad.

I wouldn't have expected this to damage the pump. Only if pumps are allowed to totally run dry for a length of time will there be a problem. They overheat and the bearings wear.
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Postby Steve the gas » Tue Dec 09, 2008 6:26 am


Need lots more info on system, but, do you have tanks in the loft?
If so, my guess is that the little one has no water in it, gently bounce the ball cock or better to replace it.

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Postby htg engineer » Tue Dec 09, 2008 6:35 pm

Are you venting the rads with the central heating turned on ? - if you are the pump will be sucking air into the system - turn the CH off when venting system.

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