Cold Rad

[steadfast01]

Guys, I know there have been many discussions on this but none of the answers worked for me.

I have a radiator that only gets warm on the flow but the rest of the rad is stone cold, I have changed the valves and if I turn all of the other rads off then it works. But when I turn the other rads on and try to balance the system, the same rad goes cold again. If i crack open the return valve then the rad gets hot through water flow and not just heat transfer.
The system is gravity fed microbore (god I hate the stuff).

I have power flushed the system (twice), after the second time, the boiler was getting up to temprature to quick and pushed the water back up into the F & E tank then kept cutting out.

I have replaced the pump and valve, also tried putting the pump on to push the water the other way, all with no sucess. The rad is not even last in the run.

Any other solutions i'm missing?

 

[twgas]

I have changed the valves and if I turn all of the other rads off then it works .
But when I turn the other rads on and try to balance the system, the same rad goes cold again. .

this points to a balancing issue

If i crack open the return valve then the rad gets hot through water flow and not just heat transfer..

I dont understand this!

I have power flushed the system (twice), after the second time, the boiler was getting up to temprature to quick and pushed the water back up into the F & E tank then kept cutting out.

I suspect your power-flushing skills are not quite what you think they are.
Do you have twin entry valves or normal (one each end of rad)?

 

[robertsamual]

I think in your case this is faulty heating pump. This can be checked only by a professional. Other reason can be air which is stopping continuous filling of hot water in the radiator. You can do it by bleeding the air off from radiator or a heating engineer can help you out.

 

[steadfast01]

Hi guys, sorry, pump is new, and now a 15-60, was a 15-50.
By means of cracking open the return valve, I mean, opening up the nut and letting water flow out of the rad into a tray.
Its a normal system, ie, has two valves on the bottom and at opposite ends.
definitely no air in system, even filled it via the return, spent 3 days on this job and now it's costing me money, to go back there.
I have isolated both valves, drained some from the rad opened up the bleed nipple then opened up the return valve and water comes out of the nipple at quite some pressure so i know the return is not blocked.
Any more ideas?

 

[twgas]

I'd disconnect the rad and try running the water into a bucket or through a hose, a bleed valve is too small to determine if a blockage exists.
Or give customer a refund, as you haven't solved his/her problem, and walk away.

 

[steadfast01]

Think thats best, Tried everything. Put it down to the one that got the better of me.
Cheers
Stu.