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Discuss Radiator Valve replacement in the Plumbing Forum area at UKPlumbersForums.co.uk.

  1. Steven Johnston

    Steven Johnston New Member

    Hi, I have an old system in the house with a fairly decent boiler, Worcester Greenstar 37CDI Combi.

    The radiators and pope work are old, I think the system needs cleaned but I also need new radiators.

    Because I’m renovating I can’t afford either done just now. I’ve noticed the valves on some are leaking but I haven’t even fired up the heating since Xmas? Any ideas why they have started dripping now?

    If I get new valves and drain the radiator system will I still be able to have hot water and stop thebsystem dripping - it’s just a shame to keep working on walls and floors to have them soaked.

    Any help much appreciated, cheers.
  2. AMGasServices

    AMGasServices GSR

    Anyone disturbed the valves ?

    That may be a the reason why they’ve started to leak or seals probably gone and also full of muck.

    I’d advice to isolate the flow and return under the boiler to make sure it holds the pressure at one bar and then start draining the heating system.

    Why don’t you try flushing your radiators yourself using a hose pipe.
    • Like Like x 2
  3. Rob Foster

    Rob Foster Top Contributor!!

    nice one AMG. connect hose to mains at one end, open pipe at another give it all a blast with rads off and then turn one onoff every hour or so. let the outgoing hose pour onto the road or concrete and you will see what comes out - it makes worms really wiggle if there is any chemicals present - saves a chemical test !
    • Like Like x 1
    • Agree Agree x 1
  4. Steven Johnston

    Steven Johnston New Member

    So to clarify, I have a drain valve on a down stairs radiator. Attach a hose to that and turn all radiators off at the lock shield.

    How do I then attach the mains to the system to flush it through? Do I just turn on the pressurising valve as if I was pressurising the boiler and leave it on?

    At what point do I let pressure through each radiator?

    Final point, I don’t know the sequence of the radiators, how can I work out which is closest to the boiler and so on so I clear the system from start to finish?

    So grateful for the time you guys have spent on this for me VMT.
  5. Rob Foster

    Rob Foster Top Contributor!!

    you have got it, isolate the boiler let the mains water into the system as you say and let it go around the system and out of the drain point through a hose with jubilee clip for good measure. dont pressurise anything. then when it all is flowing all dandy open one rad at both ends and repeat for them all in turn. as said dont let the water go into a drain but somewhere you can see its colour. the road outside is good
    you can also gently vibrate the rads esp along the bottom to activate the sludge - if you have a good magnet this is even better. yu should get loads of ferric black sludge its quite satisfying better tan pressure washing your drive. let us know how you get on. any black sludge on your wifes carpet comes of with gas leak detector spray
    • Like Like x 1
  6. Harvest Fields

    Harvest Fields S. Mod Trusted Plumber GSR Top Contributor!!

    Make sure you secure the hose to the drain off.
  7. Steven Johnston

    Steven Johnston New Member

    Sorry guys but still in the dark about how to “isolate the boiler” and how if not through the boiler pressurising valve how to “let the mains water into the system”? All I k ow how to operate is the valve on the base of the boiler to pressurise the system (always needs it) and the lock shield and TRV’s. I can connect a hose securely to the drain valve easily and have one rigged to go but don’t know how to introduce ‘other’ means of mains supply?

    Sorry if this is billy basics but I’ve no experience, thanks again for tolerating day 1 week 1 questions
  8. Rob Foster

    Rob Foster Top Contributor!!

    its ok...you have the mains water supply as you say. you dont need another - if you had a conventional system you would. isolate boiler ....there will be a shut off valve under the boiler on the flow and return pipes to/fro rads....we were all billy basics once
  9. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Time to get a pro in my recommendation
    • Agree Agree x 1
  10. AMGasServices

    AMGasServices GSR

    Please take and upload a picture of the valves under the boiler.
    • Like Like x 1
  11. Steven Johnston

    Steven Johnston New Member

    White square knob is to pressurise the boiler

  12. Steven Johnston

    Steven Johnston New Member

    Soaking and the nut doesn’t seem to have any play?

  13. Harvest Fields

    Harvest Fields S. Mod Trusted Plumber GSR Top Contributor!!

    New gas run at some point then?
  14. Steven Johnston

    Steven Johnston New Member

    Yes, 2 years ago
    • Like Like x 1
  15. Rob Foster

    Rob Foster Top Contributor!!

    white one to send mains into system then out thro the drain off. turn off central heating boiler with the two black knobs on the bigger pipes not the small pipe thats to the hot water. whats the unsoldered fitting not doing ?. leave the rads alone now and just flush it all thro. tell us how you get on.....off to a funeral
    • Like Like x 1
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