plumbing question?

Question

I have one cold radiator in the house, all the others are fine. The hot feed pipe into the rad is hot and the outlet pipe is warm.
I have bled the rad and it is fine
I have turned off the outlet pipe and kept the inlet pipe on and i have opened up the bleeder and water comes out so that means the input valve is fine ok, right?
Whats wrong with it? I reckon its one of the Locksheild valves causing the problem. There are no TRVs by the way

Answer 1

Hi UK plumber here, as stated earlier it could be full of silt, this happens usually to the last rad on the system. You will need to flush it out.
If a gravity system it may need balancing as the flow rate ( inward water ) does not push the return ( outward water ) correctly, try opening the lock-shield slowly on the return side slowly to balance.

Answer 2

Try shutting down the hottest rads, beginning with the ones nearest the pump. Assuming that your cold rad is not sludged up and pump is fine, turning off the other radiators will allow the flow to increase through the cold rad. If it does get hot, balance the system (adjust lockshield valves, ie, outlets from rad). The rad lockshield valves should be barely open on rads near the pump - and more open as you move further from pump. Hope this helps; a little tired at the moment after hard day charging small fortune for your very same problem !

Answer 3

first of all shut both valves,and open the air vent this will tell you if the valves are holding.remove the radiator and flush with hose pipe.make sure you grip the valves when undoing the side nuts on the valves.before putting the radiator back open each valve in turn. if it is a combi boiler you will have to keep re-pressurising system while you flush water through valves.if this does not work turn of all radiators in house, except the one that will not heat up,if it heats up it is a matter of balancing the other radiators untill they are all the same temprature. if all else fails the pump may need replacing.if it is a tank fed system check the ball valve in the small header tank is not stuck

Answer 4

It sounds as if this is an old radiator and muck has accumulated inside restricting the flow. This often occurs if corrosion inhibitor has been omitted form the system. Remove the radiator and hose it out. Before replacing, place a container under and in front of each valve and carefully open it to check flow and possible clear any debris.

It may be worth while putting some de-sludging solution in the system, draining and flushing after 4-6 weeks and then refilling and adding inhibitor.

Good Luck.

Answer 5

Hi, take off the cap from the outlet valve ,turn it right up .you can try turning off all the other rads. it may help to free any airlock in the system .Have you got 2 bar pressure on the system?if it it a combi boiler.

Answer 6

bleeding one rad is not the solution.
the system may well need to be done and is usually the best option anyway.
maybe the pump is not working to capacity therefore the hot water is not getting moved round the system?
some pumps i know are on a seperate switch and need to be switched on rather than relying on the system to auto start it (maybe they all do, i am not a plumber) so this could be worth checking also.
good luck

Answer 7

I had a rad like yours, in the end I had to take it off the wall and flush it thru to solve the problem.

Answer 8

For DIY go with Ed Snow, If that dont work call a plumber

Answer 9

I don't know the answer to your Q, but you might try calling home depot, or lowes, ask for someone in the plumbing dept, ask them your Q, I bet they can help you.