Bleeding new CH system

[timtheenchanter]

Ive just had a new CH system installed, I just wondered how many times I am likly to need to bleed the first couple of rads on the system until it settles in? Im up to 5 times in 3 weeks so far, with approx the same amount of air in each time ( a good couple of secs to bleed it)

just want to know if I need to call anyone back yet, the installers didnt mention it would need doing, but hey ho.

 

[beezo]

that sounds alot mate.

are you sure you bleeding them correctly.


this is what i do. fill system up to approx 2 bar when cold (do not do when hot or warm). bleed one radiator at a time. starting downstairs and working up. after bleeding one radiator, ensure that the pressure has not dropped below 1.5bar, top up to 2 bar again if nessercary. move onto next radiator. continue until all radiators have no air in.

on the final radiator, draw off water until pressure on boiler is approx 1.5 bar.

when this is then done. fire heating up and the next day repeat as above to remove air that has been pushed out of pipe work. u should not have to do it again unless there is a probelm

 

[beezo]

forgot to add but sometimes a couple of secounds is not long enough to bleed a radiator. continue to bleed until no air at all comes out of radiator, dont worry about the amount of water coming out but again ensuring pressure does not drop below 1.5bar

 

[timtheenchanter]

thanks, thinking about it, its probably nearer 10-15 secs each time, I will do as you have suggested tomorrow (the systems a bit warm now)

its only the first 2 radiators that seem affected, fine for a couple of days, then go cold, bleed and theyre fine.

 

[Jezzy]

I'd check for leaks around the valves of the radiators, and the blow off pipe outside also. You might have a leak that is under the floorboards of the rads that are losing pressure. Are you losing pressure on the boiler also?

 

[timtheenchanter]

no, boiler pressure is ok, just the first couple of rads seem to be affected. ones in the babys room, its only a 300mm rad so doesn't take much to make it ineffectual.

 

[twgas]

If you don't lose pressure when you bleed it I would suspect it's gassing, which means the system was not cleaned and/or no inhibited.