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Drain cock leak.

Discussion in 'Plumbing and Central Heating' started by ray316, 18 Feb 2021.

  1. ray316

    ray316

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    I’ve just noticed that the drain cock on my combi central heating has a slight dripping coming out the end where you open or close and the drain opening , l presume it could be the seal .
    The only reason l looked was the water pressure is low every few weeks so would this be the cause of the low pressure as all the valves are ok.
    The drain cock it self is fairly new and never been touched to drain down so can’t understand why it has started weeping now. It is the Type B and someone said l should have a Type A fitted as the one fitted always leak .
    Is there any plumbers tips l can use to stop it weeping without having to get the system drained ..
     
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  3. cross thread

    cross thread

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    Have you tried tightening it
     
  4. ray316

    ray316

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    I cannot tightening it any more than it is .
    I do know what and where the drain cock was from and could get buy a new drain cock to replace just the square nut and attached washer as the body of the drain cock is soldered and doesn’t leak.
    I wonder if l could whip out the old nut/washer quick enough and replace with new part without getting to wet , obviously blocking off the drain part while doing this or wouldn’t this be a good idea .
    Is there any way l could relief the water pressure while doing this or do l just drain down .. Any one tried this before.
     
  5. Nige F

    Nige F

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    Not a good idea, in fact attach a hose and lead it to drain ( as you would if emptying the system ) You can whip out the brass bit but the washer will stay behind - so have something to pick it out. Then go with the new setup. If it's over a carpet - pull it back a yard ;). Like I did on a job - and the customer queried it - then an old pipe broke off in my hand ! Customer was happy to have a carpet fitter re stretch the floor covering.
     
  6. ray316

    ray316

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    So by attaching a hose to drain , will most the water go down the hose giving me another time to take out the faulty nut and seal without losing to much water.
    I also thought the seal was attached to the nut when undone and removed.
     
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  8. Nige F

    Nige F

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    You have a chance - with an assistant - to put your thumb over the end where the plug unscrews, then the water will go down the hose. The seal will 99 out of 100 time come off and stick inside. The only ones I've seen that didn't were old 3/4 inch screwed brass ones with a proper thread and nut holding the washer. Most are just pushed onto a stub.
     
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  9. MeldrewsMate

    MeldrewsMate

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    Assuming the only expansion vessel is the one inside your combi boiler.
    Go and buy some MT-cock washers.
    1. Get the system up to full operating temperature.
    2. Turn the power off at the fused spur, and close both the flow and the return valves. Close any automatic air vents, and bleed upstairs rads.
    3. WAIT....until the rads are cool/cold.
    4. Attach hose to drain cock, and open the drain....it may discharge a couple of pints before the flow stops, it may not flow at all.
    5. CAUTIOUSLY unscrew the drain cock by hand, the jumper may be stuck, and there may be pressure behind it, so have a plan ready to block the end of the fitting (a finger is good only if the system is cold).
    6. Pick out the stuck jumper, and the remains of the MT-cock washer. Clean the drain cock sealing face.
    7. Attach new MT-cock washer, and re-assemble....finger tight plus 1/4 turn.

    Job done. Open the valves and top-up the pressure, etc. It shouldn't take much extra water. Put on a brew.
    Tell the missus you need some more parts, and have an hour to yourself. (she'll never believe that it was so easy; encourage those thoughts)

    MM
     
  10. ray316

    ray316

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    Thanks for the replys , l’ve still got the drain cock dripping on the heating system and will get it drained and replaced soon but for the time being is there any ideas for a quick fix .
    I was thinking about a bit of garden hose cut to fit over the drain opening and the nut opening and tighten a small jubilee clip over them .
    I don’t know if there is any end caps that could do this or not , any suggestions.
     
  11. TimboTwo

    TimboTwo

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    Put a hose on the outlet to drain.
    Unscrew the drain cock till you have about 3 threads showing.
    Wrap some PTFE tape around the threads and screw it back in.
    That should stop it leaking out there.
    Put a short bit of hose over the outlet and block the end. Secure with jubilee clips .
     
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