1 x Rad = cold at bottom/hot at top

[rocketmanbkk]

Dear Friends

as above, bleed it? Balance it?

Thanks as always, all guidance appreciated.

Regards to all

Rocket

 

[Mike Jackson]

Couls be two things, balancing or sludge. An easy check to see if balancing is the issue is to shut down all of the other rads. If it now gets hot top to bottom the sustem needs balancing. If it's still cold at the bottom it is sludged up.

 

[Phil B]

I would shut all other radiators off at BOTH valves and force to the affected radiator.

Sounds either blocked or air locked.

 

[rocketmanbkk]

Thanks, it's a new rad i put in 2 weeks ago so should be balancing, hopefully.

 

[GQuigley67]

is the lockshield fully open ?

 

[Phil B]

is the lockshield fully open ?

Sounds like it, especially if they state it's been in a couple of weeks.

Air locked if lock shield is open.




Is there a drain off valve connected to pipe work under the radiator?

 

[rocketmanbkk]

yeah, open, it worked well for two weeks but went up earlier and cold at bottom. I'll have a look, should be able to sort it, good practice anyway.

Thanks all.

 

[rocketmanbkk]

sorry, no drain valve

 

[Phil B]

I would still shut all other radiators at both valves and turn system on, see if you can force the air lock through.

 

[GQuigley67]

I don't think its an airlock I think the hot water is being circulated around the rad taking the easiest route and leaving the cold heavier water at the bottom of the rad due to the lockshield being open full, the water will take the path of less resistance, you need to adjust the lockshield valve

 

[Phil B]

I was thinking air locked return..

 

[rocketmanbkk]

Thanks Quigley, i'll update tomottow when it's fixed.

 

[GQuigley67]

depends if the return is hot or stone cold, are the flow and return both hot and just the bottom/middle of the rad is cold ?? or is the return pipe cold also ?

 

[sparra1100]

ad bet me boots its air quigley and being upstairs aswell ad just bleed it into a bucket till it bleeds through all the air plus it was working fine so no other reason that i can think of

 

[rocketmanbkk]

both pipes hot

 

[sparra1100]

rocketman try bleeding it thro into a bucket thro the bleed vent might take a while but should come thro sometimes need to do it cold as the cold wont overcome the hot but ad give it a go

 

[rocketmanbkk]

Ok, I'll try it. Cheers

 

[sparra1100]

Ok, I'll try it. Cheers

you could also try turning the 2 nearest rads of to it at the lockshields aswell ave had to do that b4 now to get it thro when hot

 

[ray]

What type of system do you have micro bore? 10mm /15 mm? Is it a combi boiler or conventional is the rad upstairs or downstairs?? and how far from the boiler, what about the pipe work is it reasonable by this I mean straight runs.. Dips in the pipe work if the pipes are under the floor?i s it the last rad on the line size of rad..how many on the sytem.. you did it yourself ?

 

[steadyfriend]

SOME AIRLOCKS ARE REALLY DIFFICULT TO REMOVE !

About 6 months ago, I had installed a straight extra radiator under a window, its pipework was tee-d off another rad about two feet away, along the skirting board, as the customer did not want the floor disturbed which had a new laminate on it.. This new small radiator wouldn't heat up, the system had a newish Valliant boiler. I tried everything, from venting it to shutting off the 13 other radiators in the house, but it still wouldn't work. I had to visit the house more than once ! Ultimately, in desperation, I took the radiator off the wall (closing both its valves) to check if there was sludge inside. Then, I opened the lockshield valve slightly, when a gasp of airlocked wind came out with an almighty hiss ! Upon connecting the radiator back, it worked normally !

The point is, closing all the other radiators to direct the pump pressure to the affected radiator does not always work.

I remembered old open vent 'non-combie' systems could have the pump either on the flow pipe or on the return pipe; with the pump on the flow pipe, 'positive' pump pressure would normally remove any airlock, whilst most modern combie systems have the pump on the return pipe and the 'negative' pressure does not always help in removing every kind of airlock !

 

[ray]

SOME AIRLOCKS ARE REALLY DIFFICULT TO REMOVE !


Well you have done something wrong for sure but what... ok the boiler you say it’s a
Combi? Boiler the Pipe work is it 10 mm or 15 mm to?
I am trying to work out in my mind the room and how the rad is fitted...
Is it in the same room you say it (was tee-d off another rad about two feet away, along the skirting board)
What size is the new rad you fitted
How did you shut the system down what did you do?
Again is it an open vented system or a closed system
There could be too many rads on the system could be! You say you have 13? Already

Removing recently fitted radiator. Dose the rest of the system have a problem example air in the other 13 or one of them, rads not getting the heat they need anything unusual

What is the boiler rating? Btu’s watts whatever!


Try turning the pump down on the heating side variable pump I would assume it will have three settings on it try tuning it down to 1, 2, 3, see what happens on say 2 then move up then see what happens.


Also do the same with the domestic pump on the boiler turn it down if it on three set it to 2



The heating pump could be Caviatating.. .. have a nice weekend

 

[ray]

what is the boiler mod and number deatiles please

 

[rocketmanbkk]

It's a conbi boiler, all working fine until yesterday, been in 5 odd years, new rad 2 /3 weeks ago, all fine until I checked yesterday, all sorted now, needed balancing, done it so another skill added!

Thank you all.

 

[GQuigley67]

whenever you are doing radiators you always have to adjust the system to suit, sometimes that means just cranking down some lockshields on some of the radiators, the closer the radiator to the boiler the less open the lockshield will be

one you finished and you fire up the heating, walk around every single radiator putting your hand to each corner of the radiator, this usually gives you an indication of whats going on and what is heating up quicker, the ones that heat up quicker then turn down their lockshields and then feel the ones which were struggling.

 

[rocketmanbkk]

OK, Greatm Thansk for that Quigley.