CH. Air noises driving me mad. Vented system.

[friendlyaviator]

Hi there, I really hope someone here can help me.

I have an open vented central heating system. Back in Dec 2011 I drained the CH system down, flushed it with clean water, fitted a new radiator to the living room and refilled with cleaner. Around a week later I drained the cleaner out, fitted TRVs on all but one radiator and refilled with inhibitor.

Ever since then I have been getting gurgling, trapped air noises while the CH pump runs when the CH is on. All radiators are filled with water and don't need anymore bleeding since I refilled the system. The pump also trickles water from the centre bleed screw when I undo it. I cannot find any other bleed vents on the system.

I am having no other symptons, all radiators get hot, the boiler cycles fine it's just this trapped air issue. I do not believe it is sucking in air as the radiators never need bleeding and as such I don't think the volume of air in the system is increasing.

I really hope you can help as the noise wakes my Mrs every morning!

Thanks,

Dean

 

[TBServices]

Sounds like your pump could be dragging in air.

 

[friendlyaviator]

Sounds like your pump could be dragging in air.

Thanks for the rapid reply.

I did wonder this but that air never reaches the radiators, therefore the air volume does not appear to be increasing. The bleed screw is tight and no leaks showing. It is a little noisy on low speed though. Could it still be the pump?

 

[TBServices]

Thanks for the rapid reply.

I did wonder this but that air never reaches the radiators, therefore the air volume does not appear to be increasing. The bleed screw is tight and no leaks showing. It is a little noisy on low speed though. Could it still be the pump?

In the op you said it weeps?

 

[friendlyaviator]

In the op you said it weeps?

You are correct. I meant when I undo it to bleed the pump. Sorry!

 

[DirksPlumbing]

You are correct. I meant when I undo it to bleed the pump. Sorry!

The air noise barely comes from the radiators except some design rads have to be filled in a certain way to overcome potential air traps.
Is it a sealed system? In this case bleed at low pressure and then increase the pressure again.

 

[friendlyaviator]

The air noise barely comes from the radiators except some design rads have to be filled in a certain way to overcome potential air traps.
Is it a sealed system? In this case bleed at low pressure and then increase the pressure again.

No it's an open vented system. F + E tank in loft. This is clean, has water in it and level reduces and tops up when I reinstalled the radiator.

I and still thinking trapped air rather than air ingestion based on the fact it never reaches the radiators, doesn't seem to be air entering if you get what I mean.

 

[DirksPlumbing]

Any specific location where the noise is dominant?

 

[friendlyaviator]

Any specific location where the noise is dominant?

Mainly upstairs but sometimes I can hear it in the downstairs radiator but when the noise comes there it sounds more of a gritty noise through the pipes instead of a bubbling.

One other thing to note is there was two capped off pipes in the kitchen at the ceiling level that used to feed a radiator. I changed these caps for two valves with the intention of adding a radiator in the future. Could this somehow contribute to my problem?

Boiler and pump situated in kitchen on ground floor.

 

[zzzjim]

What brand TRV and is the radiator without one nice and queit ?