Bleed the air out or not!

[adderzigzag]

Hi,

I've had an upright radiator installed in my bathroom, its the highest raditior on the system. Its a pumped system. The top of the rad felt cold (top 4") so i let some air out from the valve at the top. I expected the rad to start to warm further up instead the amount of cold space at the top increased (to about 24"). Any thoughts!

Nigel

 

[adderzigzag]

Hi,

I've had an upright radiator installed in my bathroom, its the highest raditior on the system. Its a pumped system. The top of the rad felt cold (top 4") so i let some air out from the valve at the top. I expected the rad to start to warm further up instead the amount of cold space at the top increased (to about 24"). Any thoughts!

Nigel

If I had a slow leak could allowing air into the system by bleeding allow remaining water to drain from the leak. Shouldn't the pressure from the header tank have refilled the system!

Is it better to bleed out of a rad with the pump running, heating on, or when the heating is off!

 

[jobloggs]

Did you bleed air until water started to come out. Your second post would suggest that air entered radiator when you opened the bleed vent.

Head from feed and expansion tank should force air out of radiators in a vented system but feed can sometimes block. See posts on this problem.

 

[adderzigzag]

No I didn't bleed it until water came out, thought best to do it a bit at a time. Is it better to do it with the pump running or stopped or does it make no difference.

Looks like a look at the header tank next, you say this feed pipe could block, if I poke something down it, wire or something if I dislodge the blockage could it upset the system elsewhere! Or would it just become lost.

Could it be the sign of a leak that air is getting into the rad or just a normal occurance due to evapouration during the water being heated.

Nigel

 

[ollski]

Depends where the rad is tee'd into the pipework, but it sounds as though the pump is on when you are bleeding it and pulling air into the system. Always turn off to bleed.

 

[Soggy_weetabix]

Cant it be pressurised out with a u guage tube attached to your blow torch and pushed down the cold feed?

Hard work if cold feed is on a close coupled and sludge has been allowed to get hard.

Sludge removal this way always ends up in pump though.

Dave

 

[JohnD]

I'd be interested to hear from someone who's used those magnetic traps.

 

[brentwood]

If you haven't bled it until water comes out how do you know the coolness is air and not cool water? Are you sure you have flow through the rad?
Has it just been fitted? Was the system drained, bunged or frozen? ie has the rest of the system refilled ok? Has it been working properly? Are both valves actually open? Has it got a straight trv? If so is the trv going with the flow? (Most straight are directional).
If the rest of the system is filling I'd guess air lock or valve wrong way around.

 

[adderzigzag]

The new rad and all the others rads were working fine till I blead out the air from the new one cause it was cold at the top. I did bleed it with the pump running and from the replies so far understand that wasn't my best idea. I would like to bleed it further as some say until water comes out but I'm worried that if the level appears to drop further in the problem radiator I will have no heat in the bathroom and if the header feed is blocked upset the system further. That would be popular with the wife! I am I just worrying, or should I bleed it!

I may wait until after Christmas incase I need professional help!, from a plumber you understand. Thanks for all the assitance so far.

 

[ChrisR]

WIth the pump off, for the level to drop you'd have to have a leak AND no feed from above.
Cover the area round the vent with big bubbles mades from a strongish washing-up liquid solution, then open the vent slowly. You should see bigger bubbles.