Tried to remove a radiator for flushing, but the nuts attaching it to the valves are encrusted in several layers of paint.
Chipped some off but wouldn't budge (not without it breaking something). (And I think I turned them the right way..)
Any ideas on how to free them up? Almost resigned to just replacing the radiator and the valves as well, but I don't want the bother of draining down the system.
Big spanner. Great care.
Agreed, can be a PITA. Threads may also be "glued" with dried up Boss White. This can be softened using a normal gas torch. Try heating the nut about as much as you would do to make a solder joint on "dry" pipe. It won't get as hot because of the water inside, of course.
The right way is the wrong way (if you see what I mean) because the nut unscrews from the valve towards the radiator, with a right hand thread. It is as if you were trying to screw something into the radiator.
You only *think* you turned them the right way? Check your thoughts against newshound's reply!
Once have have made sure that you really know the *right* way to turn them, you will need a spanner with a long handle in order to get sufficient leverage. Make sure that the spanner is a tight fit, because you don't want it to slip under load. But if that's *all* you do, you'll find that the valve will also rotate, and will bend - or even break - the copper pipe, with undesirable consequences. So you need to hold the valve with something else, to stop that happening. I sometimes grip the body of the valve with a Mole Wrench, applied from above, so that the stem of the valve goes inside the wrench (but isn't gripped by it). I use tape or rag on the valve body before applying the wrench, to avoid damaging the chrome. It sometimes helps to have two people if possible - one holding the valve and the other turning the nut.
Rotate it both ways back and forth, even if it only moves a tiny bit it'll gradually loosen up
NT
Leave it until next summer when you won't need the central heating
It does depend on the valve though... some have a traditional cone joint where the nut is retained on the rad tail and screws onto the valve. More recently the tails seem to simply have a protruding length of chromed 15mm Cu pipe, and the valve in effect has a normal compression fitting that tightens onto the pipe stub. Needless to say they undo in the other direction.
(the new sort allow a little lateral adjustment of the valve relative to the rad)
The fun party trick is when you do all that, and the mounting lugs on the back of the rad break away from the rad and the top of the thing then falls away from the wall under leverage!
And a leg pushed against the rad if you are levering the top "out"
Excellent point, I have just fitted a couple of these myself. But they do seem to be a relatively new development. Very valid points also about gripping valve and providing reaction force to radiator.
But to repeat earlier point, I have been pleasantly surprised how linseed oil based sealants do soften up on heating.
I'm not sure what you mean by that - the "other direction" from what?
Surely, whether it's a cone joint nut or a compression nut, they both screw onto the valve from the rad side, and both have to be unscrewed clockwise when looking from the valve to the rad.
The reaction force on the radiator is not one I would have considered, until I ended up changing my whole kitchen rad rather than just the valve as I had intended! (SWMBO's comment about "that one always was a bit wobbly" made more sense when I realised the left lung had obviously broken off years ago. The one remaining one objected to my manhandling!)
Yes, come to think of it I might be talking spherical objects ;-)
They are the "other way round" in the sense that the valve notionally fixes onto the tail, rather than the tail fixing to the valve - however the rotation direction should be the same as you highlight. (and once fitted the backnut is still captive on the rad due to the olive)...
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