Bleed vents on Radiators.

[Vorny]

I have recently drained down a gravity feed central heating system,(up stairs only) and installed a towel rail in the bathroom.
When draining down the system I was unable to open the vents on two of the radiators, when filling the system back up I was not able to bleed the air from the two rads with the faulty air vents, so these two rads are not getting hot only warm at the very bottom of the rads.
Any suggestions on how to sort this problem out would be of great help.
Have considered of really trying to force the vents open but didn't want to break the bleed nipple if I can help it.

Many thanks!

 

[JohnD]

The bleed nipple is probably set in a larger screw-in plug which is replacable. Is it recessed into a hexagonal hollow?

If not please post a photo

see //www.diynot.com/forums/viewtopic.php?t=129539

 

[Vorny]

The two radiators in question are old panel radiators with just the bleed nipple, no replaceable air vent.
Thanks for quick reply.

 

[JohnD]

how about that photo?

 

[Vorny]

Here is a picture of a similar one and yes it is in a hexagonal hollow not a circular hollow as picture shows.

Untitled

• Vorny
• 11 Jan 2011
• 1

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[JohnD]

this will unscrew the old plug. You can buy a new one, with bleed nipple and pin. Turn off both rad valves first to prevent leaks. Clean out the old thread with wire brush or green nylon kitchen scourer. Wrap PTFE tape round the thread of the new plug before fitting. The new one might be chromed and might fit an ordinary spanner. Buy a few and replace all your jammed or worn ones in one go.

http://www.screwfix.com/prods/11467/Hand-Tools/Plumbing-Tools/Radiator-Tools/Radiator-Spanner

 

[WabbitPoo]

JohnD - does that tool somehow fit over the small square nipple in the pic? Interested cos I have same nipples in some of my rads

 

[JohnD]

yes. The wrench fits the socket in the plug, like an Allen Key, but it has a hole drilled in the end so it can go in, over the protruding nipple. You can see the hole in the product picture when you enlarge it. It is preferable to unscrew the nipple if you can.

The wrench will also fit the blank plug in the other end of the radiator, they occasionally leak or have rust stains. Cleaning them up and wrapping the thread with PTFE tape will usually help.

The larger hexagon of the wrench fits the internal hex on older radiator valve tails. more modern ones have an external hex that an ordinary spanner will fit.

 

[WabbitPoo]

thanks. looks like a useful tool!

 

[Vorny]

All fixed now, many thanks for all your help.

 

[WabbitPoo]

Did you use that tool?

 

[Vorny]

No as the bleed nipple was screwed directly into the radiator but I did manage to get the bleed nipple out, by using some long nosed pliers and a bit of elbow grease.
Thanks again for all your suggestions,