Radiator Not Working

B

Ballyman

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Hi

The radiator in my dining room doesn't heat up like the rest in the house. It's only lukewarm while the others are piping hot.

I bled the rad but there was no air in it as water came out the second I opened the nut. I have checked the temp of the inlet and outlet pipes to the rad and these are only lukewarm also compared to all the others. It only seems to be a recent problem (last few weeks) as I would have noticed if it wasn't working properly before that.

I have a total of 8 rads. 4 upstairs and 4 downstairs.

Anyone have any idea what the problem might be??
 
Have exactly the same problem in the upstairs bedrooms since the weekend. Eagerly awaiting a reply.....
 
Try opening the lockshield valve( the one on the other side to the main control valve but be sure to note the number of turns you give it as then you can lock it back to its original position if you need to. Also check the main valve is fully open.
 
How old is the system? a plumber advised a friend of mine with 15 year old house that if bleeding the radiators doesn't work, the system might need flushing out (presumable, dirt rust in pipes is impeding water flow).
 
HighFlier said:
Try opening the lockshield valve( the one on the other side to the main control valve but be sure to note the number of turns you give it as then you can lock it back to its original position if you need to. Also check the main valve is fully open.
Click to expand...

Main valve is fully open.

What does the lockshield valve do?? I mean, what is it there for?
 
The lockshield valve restricts the hot water flow through the radiator so that all the radiators get their fair share of hot water. If it is too far open and is closer to the boiler than other radiators then the water will short circuit and leave other rads cool. If it was'nt disturbed then the performance of the rad should not have changed but check and see if it makes any difference.

Also if someone tampered with a lockshield valve on another rad it could affect the one you are having trouble with.

To adjust pull off the cap and turn anti clockwise to open. You will need a pliers or vice grip to catch the tab. Be very sure to count each half turn so you can return it to its original setting if this does not work.

If it does work only open the lockshield to the minimum position where you get satisfactory heat to avoid disturbing the balance of the other rads.
 
If it's a simple rad with a straight forward twist on/off knob on each end then you want to let the in pipe fully open with the out pipe only slightly open (close the out pipe fully and then open less than one turn) . . the hottest pipe should be the in pipe.
 
If it's a relatively new system and so you can rule out the possibility of sludge buildup you could try a tip I got from a plumber recently. He suggested switching off the system, closing all rads except the faulty one, then re-starting the system.

I'd be fascinated to know if it works so perhaps you'd keep us posted?
 
michaelm said:
If it's a simple rad with a straight forward twist on/off knob on each end then you want to let the in pipe fully open with the out pipe only slightly open (close the out pipe fully and then open less than one turn) . . the hottest pipe should be the in pipe.
Click to expand...

Doing this, as mentioned above, will knock the system out of balance. So you may lose heat to other rads. See the link in this previous post on how to balance the system.
Leo
 
Leo said:
Doing this, as mentioned above, will knock the system out of balance. So you may lose heat to other rads. See the link in this previous post on how to balance the system.
Click to expand...
I'm sure you know more about this subject than me Leo but just to say that my suggestion is based on my own simple 10 year old system . . I have all rads set as I have suggested and it works fine for me.
 
Simple thing to try if just 1 radiator isn't working is to turn the rest of the radiators off and just leave the one not working open and the pump should then push the airlock out of it. No need to touch the balancing valves at all. With most new houses the radiators downstairs are fed from above and it's not a strange happening for 1 radiator to airlock like this.
 
You should check all your rads for air including the upstairs rads. if they have air in them they will cause the system pressure to drop which will starve the rad furthest from the boiler. Also make sure the valve that feeds the hot tank coil is not fully open as this will cause short circuiting. For info I have that valve set at about 1 quater open.
 
I get that problem every now and again. They have always been air locked. Try letting the air out of them and see if that works.
 
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