Radiator Bleed Valve stuck

Postby sammydarlo » Thu Dec 13, 2007 10:05 pm

One of the bedroom c/h radiators and the bathroom radiator both need bleeding. :roll:

I know how to do it, BUT i can't get the bleed screws to unscrew (probably corroded in?- the system is around 5 years old, although there was inhibitor added to the system), i have tried several of the brass square hole keys but they just keep slipping and i presume the bleed screw has rounded off?

The bleed screw is at the back of the radiator so not easy to get a look at or see it physically, any suggestions? ( far simpler to see when they used to be at the ends of the radiators) :roll:

I did try araldite :idea: [u]into one of the rounded off keys [/u]and keeping it in position on the bleed screw 'peg' till it had hardened but despite glueing on fine it was still too "tight" to unscrew the bleed plug and eventually the glue gave way.

So short of removing the radiator and replacing it :( (remember i'll not be able to drain it down effectively as i can't slacken off the air bleed screw) do any heating experts have any suggestions or ideas :idea: :?:

Many thanks in anticipation. :D
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Simply Build It

Postby peter the plumber » Fri Dec 14, 2007 6:17 am

Its sounds like you have one of the “cheaperâ€
peter the plumber
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Postby sammydarlo » Fri Dec 14, 2007 5:18 pm

Hi peter, many thanks for the reply.

Yes i'm sure its one of the cheaper ones as there is no nut into which the bleed screw actually fits which would come out and be replaced instead, it just screws direct into the radiator, your answer was the one i was probably expecting but i was hoping that there might be a crafty way round it.

Thanks anyway, much appreciated, looks like a pair of new radiators then as the bedroom one is the same with a 'stuck' air bleed screw. :(
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Postby roger196 » Sun Dec 16, 2007 8:03 pm

Hate to state the obvious, but are you unscrewing in the correct direction?
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Postby sammydarlo » Sun Dec 16, 2007 8:41 pm

Unfortunately yes :lol: (anti-clockwise) i've bled it previously, but i appreciate you asking, as a sparky myself i sometimes 'ask the obvious' too where leccy questions are concerned, so i understand where your coming from, thanks anyway tho'. :D

I'll try squirting some more WD40 or releasing fluid on it and leave it a few days to soak in and try the glue idea again with a better quality of araldite (it was only a cheapo version i originally tried it with) its a bit near christmas now to be messing around with darining and getting new radiators and i cant think of anything else :(

It cant harm if my only other alternative is a new radiator anyway. (or to try and get the bleed valve out with the radiator removed :wink: )

Any other thoughts ideas still welcome?? Cheers. :D
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Postby roger196 » Mon Dec 17, 2007 4:23 pm

The engineering solution is to drill out the bleed screw with a left handed drill. If you have a friend to borrow one off, otherwise Tracy Tools down in Devon sell these. Or use a conventional right handed drill followed by a screw extractor or tap left handed. The tapping action usually unscrews any stuck screw. However the cost of the tools and the time taken will vastly exceed the cost of a new rad.
If you have used WD40, you will have to very thoroughly clean the area to have any success with araldite or similar.
I wonder whether someone has replaced the bleed screw cross-threaded which is making it so difficult to shift.
Good luck anyway.
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Postby Buggsy » Thu Jan 10, 2008 8:03 pm

Drill a small hole (about 1/8inch) near the top of radiator (somewhere not obvious) this will let the air out. To reseal hole use a self tapping screw with PTFE wrapped round it>
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Postby htg engineer » Thu Jan 10, 2008 9:05 pm

You can remove the radiator without draining the system. Just turn off both radiator valves and remove using your thumbs to cover both ends. If a large radiator you may need a hand.

Once the radiator is off you should be able to get a grip of the nipple with pliers.

If you get the nipple out, you can get replacements then refit the radiator.

Hope this helps
htg engineer
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Postby Steved » Mon Feb 11, 2008 7:01 pm


I have the same problem. The air bleed nipple was stuck in what I understand is an older type of radiator. I managed to remove the nipple but it is now worn down. I cant find a replacement. Does anyone know where to obtain such replacements?

Many thanks,
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