Problem with Airing Radiator

[GQuigley67]

I've came across this problem twice in the past fortnight, the first time was in a household, with a combi boiler. I had the pressure set to 1.5bar, and the Radiator was on the 1st floor and so was the boiler.With the boiler on, the Radiator was hot at the bottom and so was the flow and return, but i had the bleed screw completely removed from the radiator and no air or water was coming out, Strange as it is 1.5bar you'd expect it to be flying out. I just said to the woman that she would need to get the system flushed, as i suspected it to be sludge.

Now I have come across this problem again, this time a Commercial sized heating system(gravity fed). when i filled it up it was fine, I bled the radiator until water was flying out, now that its been running for a few days, i went around to air the radiators again and same problem. The Radiator is on the top floor(building is B,G,1,2) and it is a long radiator think it is 3 joined together, It is hot half way along, and at the other side when i try to bleed it no air or nothing comes out. I've tried shuttin the lockshield to force it out but doesn't happen. is it a build up of sludge ? i am in the process of flushing the system as it is around 30 years old and i have added the sludge remover.

Does anyone know what the problem is ?

 

[Gray0689]

I've came across this problem twice in the past fortnight, the first time was in a household, with a combi boiler. I had the pressure set to 1.5bar, and the Radiator was on the 1st floor and so was the boiler.With the boiler on, the Radiator was hot at the bottom and so was the flow and return, but i had the bleed screw completely removed from the radiator and no air or water was coming out, Strange as it is 1.5bar you'd expect it to be flying out. I just said to the woman that she would need to get the system flushed, as i suspected it to be sludge.

Now I have come across this problem again, this time a Commercial sized heating system(gravity fed). when i filled it up it was fine, I bled the radiator until water was flying out, now that its been running for a few days, i went around to air the radiators again and same problem. The Radiator is on the top floor(building is B,G,1,2) and it is a long radiator think it is 3 joined together, It is hot half way along, and at the other side when i try to bleed it no air or nothing comes out. I've tried shuttin the lockshield to force it out but doesn't happen. is it a build up of sludge ? i am in the process of flushing the system as it is around 30 years old and i have added the sludge remover.

Does anyone know what the problem is ?

When you bleed rad is nothing coming out (ie air or water)
Try getting a pin and push in to bleed hole probably got crap stuck in bleed hole

 

[GQuigley67]

When you bleed rad is nothing coming out (ie air or water)
Try getting a pin and push in to bleed hole probably got crap stuck in bleed hole

i don't think so, its weird when i was putting the screw back in, then taking it out, air would come out for a few seconds then stop again.

 

[WHPES]

Try pushing a bit of wire right into the hole and through into the radiator, probably rubbish in bleed hole as stated. If that doesn't work then you have a blockage in the pipework, or a gate valve not open.

 

[PlumbingSucks]

regarding the gtavity fed system i had the same problem on a domestic gravity system. the rads wern't working upstairs at all and apeared they were all full of air and couldn't bleed them. thought air was coming out then stopping. It turned out that it was a negative system so if you bleed the rads with the pump going it sucks air into the vent on the rad . Took me a while to realise this. Have a feel for the air or put a small piece of toilet paper over the vent and see if it sucks it to the vent. i bled it with the pump off and now works fine.

 

[GQuigley67]

regarding the gtavity fed system i had the same problem on a domestic gravity system. the rads wern't working upstairs at all and apeared they were all full of air and couldn't bleed them. thought air was coming out then stopping. It turned out that it was a negative system so if you bleed the rads with the pump going it sucks air into the vent on the rad . Took me a while to realise this. Have a feel for the air or put a small piece of toilet paper over the vent and see if it sucks it to the vent. i bled it with the pump off and now works fine.

sounds about right mate because the pump is on the return, and im pretty sure it is sucking air in, as i though i could feel that when i put my finger over the vent. But as the same thing happened on the combi at 1.5bar except the rad was hot at the bottom and freezin at the top, i dunno if that was a build up of sludge, as it was a single panel radiator.

So what your saying is I will need to turn off the pump to get remaining air from the system ?

 

[Gray0689]

Why do you have to have pump on to bleed rads ?????????????
Bleed without pump on

 

[PlumbingSucks]

i bled it with the pump off and now works fine.[/QUOTE]

 

[GQuigley67]

Why do you have to have pump on to bleed rads ?????????????
Bleed without pump on

I initially bled the system with the boiler off, but as i was going around checking the radiators a few days later i was jst tryin to get remaining air out of the system

 

[Twinhawk]

i came across this problem when some oul ******* had me replumb his house and stick his radiators back on, after telling him on several occasions the radiaotors goosed he insisted on putting them back on. had to go back and bleed them after the system was drained for some apparent reason a few weeks ago and put a pin in and hit it with a hammer (and my thumb in frustration with him because i told him about the radiators and he insisted it was my fault) untill water came out