Cold radiator

[Dave1000]

Hello everybody. I have used this fantastic website many times and saved myself many callout charges, just from mining the forums for information and advice. However, I have run out of ideas and therefore need to post my problem. I have 2 radiators in the living room, both the furthest away from the boiler. It is a simple open vented system. The 2 radiators are cold. I have done the following: put cleaner in the system followed by inhibitor, rebalanced the system, taken off both radiators and flushed them with a hosepipe. Turned all radiators off but the 2 in question - still not working. The frustrating thing is they worked really well for a day when I first flushed them but now nothing. The water is hot to the inlet pipe to the radiator but will just not flow into the rad - but I have flushed it out!! What could be the problem? A blockage in the return pipe? If so, how can I flush the pipes without damaging the system? As an aside, I have turned the pump from 1 to 2 and it just forces hot water up the exansion pipe and heats the expansion tank nicely! Does this also suggest a blockage somewhere?

Please help as my wife is putting me under pressure to call a plumber out and admit defeat!

Many thanks in advance, Dave1000.

 

[Agile]

If you cannot put the pump on "2" there there is certainly some serious problem.

As far as the rads are concerned, you could remove them and then open each valve in turn into a bucket and see if a good flow comes out and that its clear.

Tony

 

[Watchmaker]

Is there a chance that the two lockshield valves,ie, those on the return side of the radiators, have collected a small amount of debris or, were they fully opened when you carried out the flushing? They are, normally, only open a small amount and, if they have not been fully opened, when flushing, any residue, in the bottom of the radiators, is likely to be carried towards them. As advised, it might help to remove the radiators and check the flow through the valves but, it would be prudent to do this with the lockshields as well. A long shot I know but, hopefully, worth a try.

 

[Agile]

When I said open each valve in turn I expected the OP to understand that I meant each valve at bothends of the rad.

The lockshield as you call it is a ( lockshield ) valve!

On many installations they are identical valves anyway with adjustable knobs!

Tony

 

[Rayzinzerbar]

do you have thermostatic valves on has the pin stuck inside?

 

[almal]

What boiler is it youve got. Have the rads worked before? it will be full of air if its [pumping over,you should be able to run it on 3 without it pumping over,so if your pump isnt on a high setting and one mightnt be enough to push the heat around then you need to find out why its pumping over and is the pump ok.I would turn it all off vent the system then open all the rads and have pump on one and see if its going and if it is what gets hot do the downstairs or just upstairs maybe just by gravity,is it a back boiler by anychance and a anti grav valve has shut maybe your cold feed is dirty,does the h/tank fill when filling system?

 

[Dave1000]

Many thanks for all the quick replies and advice. Most worrying is the comment that running the pump on high and water venting over into the expansion tank suggests a problem. Surely the path of least resistance will be followed by the water if the pressure is suddenly increased? Secondly, the boiler is a floor standing one in the kitchen - a Mexico Super FF gas boiler size FF60. It must be 10-15 years old, maintained annually until I bought the house last year! The pipes in the house must be the original ones - the house was built in 1974. None of the rads have TRVs on them just the old turny valves. When the system comes on, the upstairs rads get hot first - really toasty. The downstairs are also pretty good - its these 2 furthest ones in the living room where it grinds to a halt. I have tried loosening the nuts after the valves and water dribbles out - does this suggest the valves are not blocked? The system is bled fine - would fitting new valves and TRVs help?

 

[algeep]

first step deffinately shut off both valves drain rad and dissconnect valves from rad open each valve into a bucket and see what flow of water is like

 

[Watchmaker]

"The lockshield as you call it is a ( lockshield ) valve!"

"is there a chance that the two lockshield valves"


Yes, as I said in my comment, lockshield valves