Another Plumbing / Rad Q

[Ballistic Banana]

Just been bleeding My Rads as just lately they have been banging something cronic.

Anyhow I find the Rad at the highest point of the House is 9/10ths full of air, why would that happen.
obviously I understand teh Air will gradually go to the highest point in the system.. But what i dnt understand is where all this air has got in the system.. No rads haev been of the wall while decorating etc for well over year now.

TIA

BB

[sheepy]

[rev-erend]

Ballistic Banana said:

Just been bleeding My Rads as just lately they have been banging something cronic. Anyhow I find the Rad at the highest point of the House is 9/10ths full of air, why would that happen. obviously I understand teh Air will gradually go to the highest point in the system.. But what i dnt understand is where all this air has got in the system.. No rads haev been of the wall while decorating etc for well over year now. TIA BB

I've not done this yet but it sounds like the answer to the problem :

http://heatandplumb.com/acatalog/Aladdin_Autovent3.h

Put one on the highest rad..

Air(OK Oxygen) is in H2o.. and gets removed but the pumping action .. I believe.

[ferg]

Auto vent is treating the symptom not the cause. The 'Air' is likely to be hydrogen due to some rusting going on. A leak somewhere alowing the system to top up with fresh oxygenated water allowing the rusting to occur is fairly likely. 'Pumping over' from the heating vent is a distinct possibility and causes re-oxygenating which you can check by taking a look in the loft when the heating is running.
The other possibility is a micro leak at the suction side of the pump or even an auto airvent 'gulping air' when the pump starts up.

[simpo two]

Blimey Ferg, is that the best you can do

I suppose you could prove/disprove the hydrogen option by holding a match to the bleed valve...

[Parrot of doom]

Well if your pipes are banging that suggests to me that you might have a valve on the wrong way around.

[dirkgently]

simpo two said:

Blimey Ferg, is that the best you can do I suppose you could prove/disprove the hydrogen option by holding a match to the bleed valve...

Yes you can but hydrogen burns with an invisible flame so you must make sure you don’t set fire to the curtains

[robinhood21]

Have you checked the expansion tank? It could be the ball-valve has stuck in the closed position and is no longer allowing water into the system.

[ferg]

simpo two said:

I suppose you could prove/disprove the hydrogen option by holding a match to the bleed valve...

We used to do that.

[rev-erend]

ferg said:

Auto vent is treating the symptom not the cause. The 'Air' is likely to be hydrogen due to some rusting going on. A leak somewhere alowing the system to top up with fresh oxygenated water allowing the rusting to occur is fairly likely. 'Pumping over' from the heating vent is a distinct possibility and causes re-oxygenating which you can check by taking a look in the loft when the heating is running. The other possibility is a micro leak at the suction side of the pump or even an auto airvent 'gulping air' when the pump starts up.

Very impressive.. nice GTM by the way

[ferg]

Thanks. It's my job though.

While we're admiring cars... Lovely T350C.