Central heating circulation problems continue !!!!!

[nairb999]

I have for sometime now been experiencing air problems as per this previous post

I have a Potterton Prima 60F Central Heating system - simple heating system with 16 rads each with TVR so no room stat. Had problems with air in the system for a number of years. Changed the pump approx 6 months ago and since then get a kettling/Whooshing noise above the pump in the feed/expansion area after the system has been running for a couple of hours.

Cleansed the system with X400 - no change.

The pipe work has since been replaced to eliminate air issues - was closely coupled H configuration. The horizontal section has been increased in length to accommodate t ing feed & vent pipes which are now much closer together and this horizontal section has also been lowered to approx 4" above the pump. This seems to have worked as no air is vented from radiators now - but gas is. Test resulted in flames from radiator bleed valves.

Whooshing noise still present but not as loud.

Decided to clean system again - this time with Fernox F3. After a week the expansion tank was black so bailed out before flushing. Flushed out whole system till water was crystal clear and added inhibitor. To my dismay still get the whoosing noise and build up off gas in several radiators upstairs on a daily basis.

Any thoughts on next steps? The whooshing noise is only there in the cycle when the boiler is on and diminishes soon after the boiler has turned off. There are no apparent noises from the boiler.[/quote]

 

[Bahco]

Try post 11 FAQs.

 

[nairb999]

Try post 11 FAQs.

As I have chemical cleaned twice with no luck could I remove the heat exchanger and clean more thoroughly. I have already replaced the heat exchanger several years ago so I know it is pretty straight forward

 

[baxpoti]

Try adding Fernox boiler silencer (it really is good and does what it says) also slow the pump speed down.

 

[nairb999]

Try adding Fernox boiler silencer (it really is good and does what it says) also slow the pump speed down.

Had thought about a silencer - will that also inhibit gas problem ?

 

[JohnD]

surely the silencer just breaks down limescale? I can't see it affecting gas production.

Might there be an air leak on the suction side of the pump?

Did you get a lot of black sludge out? Fit a Magnaclean and you will enjoy seeing how much it traps.

 

[foley74]

Why not think about getting the system pressurised,just a vessel in place of the tank,its much better for a system that size which is getting proplems,with auto air vents fitted,air will find its own way out,i would put some internal leak sealer in as well,it sounds like your losing water somewere

 

[nairb999]

Thanks for all the suggestions.

If I have cured my initial air problems through pipe changes and I am getting gas when I bleed the radiators - is the gas purely down to problems within the the heating system and not air making its way into the system.

I read the FAQ11 and that lead me to conclude that I either have a problem in the heat exchanger or the long horizontal run from the boiler to the pump ie 7-8 metres.

 

[nairb999]

Thanks for all the suggestions.

If I have cured my initial air problems through pipe changes and I am getting gas when I bleed the radiators - is the gas purely down to problems within the the heating system and not air making its way into the system.

I read the FAQ11 and that lead me to conclude that I either have a problem in the heat exchanger or the long horizontal run from the boiler to the pump ie 7-8 metres.

As per my original question would it be benefitial to remove heat exchanger and thoroughly clean/flush ?