Just one radiator in system won't heat up at all

Discussion in 'Plumbers' Talk' started by SkiTuscanyCom, Dec 6, 2010.

  1. SkiTuscanyCom

    SkiTuscanyCom New Member

    Hi there!

    I have a radiator problem which doesn't seem to be answered by previous posts, so I wondered if anyone else has any ideas that might help me?

    One radiator in my system will not heat up AT ALL.

    I have tried:
    1. Shutting off all the other radiators
    2. Draining down, removing and flushing radiator with a hosepipe - it was full of black water whereas the system had clean brown Sentinal inhibitor.
    3. Replacing the TRV and lockshield valves with new ones and fully bleeding the system

    It still won't heat up at all.

    It's a 10mm microbore system.

    Any ideas?

    Many thanks!

  2. M20 Plumbing

    M20 Plumbing New Member

    Try shutting off all the other radiators again as you may have introduced an airlock when you drained down and fitted the new valves.

    Failing that it sounds as though the pipework is blocked. You'll need to check that you can get a reasonable amount of water out of the pipework on either side of the radiator - doing this can make quite a mess if you get it wrong!
  3. SkiTuscanyCom

    SkiTuscanyCom New Member

    Thanks M20. I will try shutting off all the other radiators again.

    In the meantime, I tried the following:

    1. I shut off the lockshield valve and opened up the TRV fully and then opened the bleed valve - plenty of water pressure and water spraying out ... seems OK, but still stone cold. Shut the bleed valve.

    2. I then opened up the lockshield valve fully and shut off the TRV fully and then opened up the bleed valve - plenty of water pressure and water spraying out ... seems OK but still stone cold.

    3. Shut the bleed valve and opened up The TRV fully. Still all stone cold :(

    Doesn't seem like a blockage or airlock to me, but could it be? M20 - what do you think?

    Many thanks!

  4. tetleyman

    tetleyman New Member

    Turn off both valves drain rad off take rad off, put a bowl under valve on one side to catch water open valve and let water run when it gets hot turn off valve and repeat at other valve put rad back on and refill rad by filling half of rad from one valve and turn off and other half from other valve then make sure you open all valves when finished
    330d and codhead87 like this.
  5. SkiTuscanyCom

    SkiTuscanyCom New Member

    Tetleyman -

    Thanks for this tip! Can you tell my why this will work and why it doesn't work automatically?

    Just curious :)

  6. Opening each valve in turn will confirm that the pipes are not blocked, and will remove the possibility of an airlock.
  7. SkiTuscanyCom

    SkiTuscanyCom New Member

    Thanks Graveyard Walker. I'll try this tonight! Many thanks to everyone who helped. I'll report back tomorrow :)

  8. I had the same problem, only mine was self-induced. Many years ago, I altered the pipework on the three radiators in the lounge bay window so that the water ran into one, then through the next, then through the last radiator before returning to the boiler. I thought at the time the flow through was so little it would make little difference, with each radiator not having its own supply of hot water. Over the years it became obvious that I was wrong and I decided to change it back. I managed to get one radiator piped to have two flows and no return. So the water was there, bled easily but wouldn't heat up. I rechecked my pipework and moved one of the pipes to a return and it started working fine. My mistake was at the manifold (mine is in 10mm pipe too) I'd misread the letters on the manifold. It may not solve your problem, as you don't say how old your system is or wether you bought it with the house etc Hope this helps, Les
  9. SkiTuscanyCom

    SkiTuscanyCom New Member

    I shut off every other radiator and opened up the bleed valve again hoping for salvation, but all to no avail!

    So then I did as I was told and sure enough there was a bit of spluttering and some black water coming out of the pipe feeding the TRV ... followed by the normal clean brown hot water. Other end spluttered a bit too, but water was clean brown.

    I'd never have believed that removing the radiator would be any different, but it was.

    Thanks to everyone who replied, but especially to Tetleyman. Your clear instructions enabled me to solve the problem 100%.

    Case closed :)

  10. ThreadJacker

    ThreadJacker Active Member

    Yes, you need a nice full bore outlet for the airlock to splutter out, opening the bleed valve is too small a hole. Thanks for getting back, most people take the free advice and run.
  11. tetleyman

    tetleyman New Member

    Thanks SkiTuscanyCom glad we all could help you with your problem,tetleyman
  12. petertheplumber

    petertheplumber New Member

    Last time I had a problem like this one I had to remove radiator with both valves closed the using a wet/dry vaccuum, on wet sucking while one valve is opened until vaccuum is full. close valve empty vac then repeat on other valve, the power of sucking on valve helps remove air locks and usually does the trick. Good luck. P.S. the vaccuums only cost £40-£50 in wicks which is a must when messing with rads in my opinion.
  13. HOTDOG ø

    HOTDOG ø Active Member

    Peter. Its bad forum etiquette digging up very old posts. Stick to the more recent stuff.
  14. Captain Leaky

    Captain Leaky New Member

    Tell him HD!
  15. petertheplumber

    petertheplumber New Member

    Ok HD got the message, I'm new to this.anyway when does post become old? 2hrs, 1 day? 2 days?
  16. G Brown

    G Brown New Member

    Well two years is certainly old! :)
  17. Minifish33

    Minifish33 New Member

    Two years, three months. I win! ;-)
    P.S. Thanks for the advice, no matter how old it is, I'll be trying it tomorrow...
  18. codhead87

    codhead87 New Member

    Thank you so much sir! (if you are still around 8 years on!)
    4 nights spent figuring out my cold radiator and this worked a treat!
  19. 330d

    330d New Member

    Thank you very much. This method has helped me.

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