Loud banging noises from pipes. No central heating!

22 Dec 2007
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United Kingdom
Today afternoon I heard some loud banging noises from the pipes/boiler. Ever since I have no central heating. I have a 8 yr old Potterton Suprima 50 boiler which now has its green light flashing. I turned off the boiler and switched it on after about an hour. Again I heard these loud bangs. I even saw the pipes near the cylinder vibrate. The noise was so loud I decided to switch of the boiler again. What's happening? Help pls.
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Check 240V at pump terminals as well, as the boiler supplies the power for the pump.
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remove the chrome screw on end of pump and, using a thin flat screwdriver, feel into hole to see if pump spinning
Ok, as your a novice as you put it, don't attempt to check the electric side of things as testing live electrics can be dangerous :eek:

We don't want you lighting up brighter than the xmas tree lights :LOL:
The pump is called Myson compact. There's a small nut on it which can be pulled out a bit and is presumably linked with the pump valves. It says on the pump not to switch on the pump till its pushed back in. How can I confirm if its working or not?
Ensure heating is off.

Put a cloth etc under the pump - you may get a little water loss.

Unscrew the plastic nut and gently pull out. It will lock into the pump rotor.

You should now be able to rotate the pump rotor and feel for binding etc.

Now switch on the boiler.

The plastic nut should rotate.
turn system off
unscrew nut, pull it out a bit and you should be able to turn the impelloor(you may get a bribble of water out so old cloths under it is advisable)
turn system on(with nut still out), nut will spin if pump is working.
turn system off again and do up nut
Looks like the pump's a goner. The nut wasn't spinning and all I could hear was a whine from the pump.

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