Leaking from feeding pipe tap to Combiboiler

[macgyver]

Please excuse my lack of knowledge of correct terminology.
I found a leak from an opening from the pipe feeding into my combiboiler.
Sorry if I am not clear. Will post a picture.
When I tried to tighten or loosen the knob on top with an adjustable Wrench and
a plyer, it is stuck and slipping. Have applied some vinegar soaked cloth on it to loosen the connection.
I do not need this tap. Can I just put some blocker or Sealant in the hole to stop the leak or any other ideas please.
Thanks for looking.

 

[terryplumb]

That's a drain cock. The square shape in the centre should be operated with a spanner to close / open the drain cock ,not pliers.
If tightening fully ,clockwise, doesn't stop the leakage it will need to be stripped down and a new washer / seal fitted.
Or a complete replacement if the square shaft end has been rounded off.

 

[Macgyver11]

Edit: Sorry it's me again. Didn't realise I have an account already and created another one.

Thanks for the reply. Yes, I used the spanner but it was slipping. Will try again after I remove the vinegar soaked cloth and try the spanner with some cloth to hold the square shaft so that it doesn't slip.
Thanks again

 

[gas112]

https://www.screwfix.com/p/arctic-hayes-mt-drain-cock-tap-washers-1-2-5-pack/6666j

take it apart and stick new washer on it

 

[macgyver]

https://www.screwfix.com/p/arctic-hayes-mt-drain-cock-tap-washers-1-2-5-pack/6666j

take it apart and stick new washer on it

Thanks for that. First challenge is to unscrew the square bolt. Have put some vinegar around it. Will get some wd40 tomorrow if it fails.

 

[macgyver]

Unable to unscrew the square bolt. Tried with Adjustable ranch after apllying vinegar and WD40 to it. Will buy the spanner for it. Need to know the size of the spanner I need to buy please. I found this on searching
Drain cock: A 7.9 mm square socket bleed key is suitable for drain cocks.
Thanks

 

[terryplumb]

Did you use an adjustable spanner ? The square looks to be badly deformed in your picture ,and a spanner may not even work if it has been rounded off. I would replace the whole valve if I were you .

 

[macgyver]

Yes I did. Thanks. I think I will need a plumber to fix it. Thank you all for the help.

 

[ChrisJP]

Before giving up entirely I would try applying proper penerating oil (not WD40), let it soak for 24 hrs and then try unscrewing it using a self-locking wrench (typically called a mole wrench) on the square bolt, done up really tightly.
Just one thought - you are trying to unscrew it by turning it anti-clockwise?

 

[oldbuffer]

Provided the stop cock below the drain off valve is working, you could easily replace it yourself:
1. Buy a new compression fitting drain off valve. Assuming the pipe is 15 mm diameter, BES Item 7802 is what you want.
2. Shut of the stop cock by screwing the handle clockwise until it won't go any more.
3. Undo the two big nuts on the drain valve, one above and one below the spout. Residual water from the pipework above will drain out. You will need either two adjustable or correct size spanners or one such spanner and a pair of grips.
4. Remove the old drain off valve, clean the pipes, and fit the new valve, spout pointing down.
5. You should be able to:
5.1 Re-use the old nuts and olives if they are the same thread (highly likely). If so use some sealing paste such as JetLube V2 smeared around the olives, or wrap 4 or 5 turns of PTFE tape around the olives.
5.2 If you can't re-use the old nuts, remove the olives (without damaging the pipe) and use the new nus and olive which come with the drain valve.
6. Tighten the compression nuts firm finger tight, then 1/3 to 1/2 turn with a spanner, holding the valve with spanner / grips to prevent it turning. You can nip the nuts a bit tighter if you get a leak
7. Make sure the drain off valve is closed (square nut tight, but not over-tight).
8. Turn the water on again to test.