Our central heating system kept filling up with gas so that the pump started screeching after only a few hours after bleeding the radiators.
So we replaced the automatic bleed valve (nearly new) with a pipe that has an upside-down u-bend near the top of the roof inside the attic so that we could be sure all the gas is getting out easily and have some idea of the quantity. This has stopped the pump screeching.
No water is escaping from the open end of this pipe - the pipe is only hot to about 3 feet higher than the pump - but there are completely regular short bursts of bubbles audible from the end of the open pipe every 4 or 5 seconds.
If you block the end of the pipe with your thumb for 15-20 seconds, there's a significant pressure build-up - noisy whoosh when you release - so the gas is not getting in that way.
I've gone around every radiator in the house and bled them and turned them off to shut down the possibilities but the regular breathing remains (though perhaps every 5 secs instead of every 4).
I tried putting a butane lighter flame in the gas that was coming out when I bled the radiators and it put the flame out immediately - is that a clue?
Boiler is an Ideal Classic FF60 - old, but still seems to work perfectly. Tank is a Stanley Indirect Cylinder that has an in/out pipe from the central heating to heat the water as well as the electric immersion heater. No leaks anywhere.
Any ideas what is causing the breathing? Given that the upside-down u-bend is letting the gas out, is there still something there that needs fixing urgently?
I've just thought to put a carbon monoxide alarm next to the end of the open tube as another test - will post later with the results.
Thanks!
So we replaced the automatic bleed valve (nearly new) with a pipe that has an upside-down u-bend near the top of the roof inside the attic so that we could be sure all the gas is getting out easily and have some idea of the quantity. This has stopped the pump screeching.
No water is escaping from the open end of this pipe - the pipe is only hot to about 3 feet higher than the pump - but there are completely regular short bursts of bubbles audible from the end of the open pipe every 4 or 5 seconds.
If you block the end of the pipe with your thumb for 15-20 seconds, there's a significant pressure build-up - noisy whoosh when you release - so the gas is not getting in that way.
I've gone around every radiator in the house and bled them and turned them off to shut down the possibilities but the regular breathing remains (though perhaps every 5 secs instead of every 4).
I tried putting a butane lighter flame in the gas that was coming out when I bled the radiators and it put the flame out immediately - is that a clue?
Boiler is an Ideal Classic FF60 - old, but still seems to work perfectly. Tank is a Stanley Indirect Cylinder that has an in/out pipe from the central heating to heat the water as well as the electric immersion heater. No leaks anywhere.
Any ideas what is causing the breathing? Given that the upside-down u-bend is letting the gas out, is there still something there that needs fixing urgently?
I've just thought to put a carbon monoxide alarm next to the end of the open tube as another test - will post later with the results.
Thanks!
and it will be getting in somewhere on the suction side of the pump pipework
