Water boiling in the boiler...

[Duke Thrust]

Chaps,

Further central heating woes...

After fitting the replacement pump and the epic task of bleeding and filling all the radiators there seems to be another problem.

The boiler is making a sound not dissimilar to a (big) boiling kettle. It only seems to have done this after changing the pump. I still hear air moving in the rads on occasion despite regular bleeding and checking. I can't see any leaking water anywhere, only the pump was changed but still checked everything for water and continue to do so.

The boiler thermostat is set to its lowest setting and all the rads are getting nice and hot no probs.

Is there something inside the boiler (Ideal Concord CX) I need to bleed?

[john_p]

Does air get trapped at the top of the boiler? On mine there is an automatic air bleed valve at the top, maybe this is struck / screwed in ?

[Tokar]

Mine did this a few weeks back. If the sound is coming from the hot water tank in the airing cupboard, it could be that its drawing air in through the tank in the loft. Check that the ball cock is floating properly and that the level of the water is lower than the overflow pipe from the hot water tank (its a vertical copper pipe on mine). Failing that you could turn down the thermostat on the boiler itself (should be around 3/4 of full)

HTH

[Ferg]

You have 'kettling' in the boiler. Is the pump turned up high enough to move the water away from the boiler?? Are the pump valves fully open? Did you drain and have you re-filled with an inhibitor?

Air pockers in the boiler ARE a possibility, but only if it's been plumbed badly. Do you have a continuously rising vent pipe off the boiler (or flow).

[Deva Link]

Did you put the pump in the same way around?

[Simpo Two]

Mine's been doing it for years. Short of soaking it in Viakal I'm not sure what the answer is, but it still seems to work as well as ever.

Edited by Simpo Two on Monday 15th February 18:03

[Ricky_M]

Check the boiler for an air vent or some sort of bleed point. Is the boiler the highest point in the system?

[Duke Thrust]

Thanks for the replies chaps, the pump is certainly flowing the same way as before. It's turned onto full speed and according to Grundfos a direct replacement for the original one. The valves are open fully and it all seems to be flowing well.

I'll check for any bleed valves on the boiler itself.

[Duke Thrust]

Ferg said:

You have 'kettling' in the boiler. Is the pump turned up high enough to move the water away from the boiler?? Are the pump valves fully open? Did you drain and have you re-filled with an inhibitor?

Air pockers in the boiler ARE a possibility, but only if it's been plumbed badly. Do you have a continuously rising vent pipe off the boiler (or flow).

Yep, to all the points in the first paragraph.

Re the second paragraph, how can I tell, what am I looking for?

Thanks for your advice!!

[convert]

Get some Fernox Bolier noise reducer into the system.