Hello all,

Since switching on the heating the other day I have a strange problem! The radiator in the lounge does not get hot. Now I have checked the thermostat valve and made sure the rad is actually on on the other end, but the strangest problem is that the feed and return pipes run along the wall and up into the ceiling and neither get hot. It worked last winter!

Does anyone have any idea what could cause this as all the other rads in the house are getting hot. The pipes dont have a shut of valve that im aware of so I havent switched it off by mistake.

Had a new boiler 4 years ago which runs heating and hot water both work fine except one rogue radiator.

Any help and advise, as usual is welcome!!

Thanks

Andy

I presume you have bled the air out of the radiators? Is there a bleed fitted somewhere at the top of the drop to the radiator?


I have had issues before in houses with microbore pipes (10mm)... They tend to be very subjective to the balance set on the radiators...

One end of the rad will have a valve/thermostati valve, the other end should have a lockshield or balancing valve... Close down the hottest radiators a bit and see if it pushes the heat into the cooler ones. Just like inreasing the resistance in an electronic circit, the flow will take the easiest route... so on long drops the flow can sometimes totally miss them unless you lock down the other rads a bit,..

Have you taken the T valve off an played with the plunger ?
I've had to take the top of the valve off a few of mine before because the valve is stuck closed.
And of course the obvious one that I assume you've done - bleed the rad ?

Unscrew the thermostat head off ( will be a big nut screwing the plastic head to the valve body)
On top of the metal valve will be a pin push down on it with something hard you shoud feel it go down 2-5 mm and when you
Release it it should spring up.
If it dont the valve is stuck shut you can some times free them off by gently working the pin up and down with some pliars if not time for new valve

I have taken the topp off the thermo valve, its not only the rad that is not getting hot but the feed pipe too. Even if the rad is switched off surely the feed pipe will have hot water down it, but its stone cold

I will close the others down a bit and see if that helps. I have bled the rad which is cold and as soon as I cracked open the bleed valve, water came out.


AAARRRGGGHHH

If no waters flowing through then the pipes will be cold

I found a load of air in an up stair rad, and although it was hot had quite a bit of air. The system gurgles and made some very odd noises and now as if by magic the rad is warming. I think I will replace the last few thermo valves as i have three old ones left.

Thanks for the suggestions guys.

Most likely cause is an air lock. If you shut the radiator valves both to off. unscrew the bleed valve and when no water flows out
remove the bleed valve complete. Insert a 1/2 " BSP straight compression coupling into rad with a short length of copper pipe.
Get ready with a bucket to catch the water. Open the rad valve to let the water flow into bucket. It should get hot quickly. Shut the valve and remove the fitting. With the bleed valve refitted open both valves and all should be well.

Other thing is to turn ALL the rads off (with the thermo valve, and not the ballancing valve).
then turn on the one rad that is causing the problem. With all the other rad shut down the water has to go thru that one open rad.

I had no hot water when I turned on the heating this autumn. I needed to "adjust" the thermo valve that goes into the hot water tank, by using an American Screwdriver on it. Only a gentle tap tap tappety tap was needed. Works fine now, and plenty of hot water.
It was just stuck shut after not being used since last year.

I have drained all my water from the heating and rads, it came out like a black syrup, more akin to oil in a knackered engine thats done 1Million miles without an oil change!

With a tub of non agressive cleaner, and a lot of pumping through one rad at a time (with all the other rads turned off) its cleaned and cleared the system.
It now runs hot and quiet.

Plumber wanted £450 to flush out my rads... I asked him if he had heard of Locostbuilders