Radiator wont heat - tried all the basic advice already

Howdy do folks.


Getting sitting room re-plastered. Plasterer arrives, removes radiator (I wasn't here for this) and gets stuck in. He finished up yesterday, but obviously he can't re-hang the radiator as the plaster is still setting when he's heading off.


So I DIY putting the radiator back on myself. Not a necessarily difficult job. For clarity, it's the same radiator and pipes that were always there. No new parts bought, and no one touched the boiler during any of this.


So I've got the radiator back on the wall, screwed into place, tightened on both sides. Stick it on full power and.. nothing.

So I reckon I need to bleed it, which I do. Leave the valve open and the air hisses out, but no water follows. I check the (combi) boiler, and it's low on pressure.

So I top up the pressure, and send the brother into the radiator to keep bleeding until the water comes. Pressure increases on the boiler, water comes out the radiator, everyone celebrates.


Check radiator a few minutes later - cold. Every other radiator is untouchably hot.

So my poor logic tells me that maybe the water is old sludgy water, so I bleed it again, until the rusty brown water is gone, and clear water is coming out. At this point, the heating is powered on, and whilst im bleeding the radiator, the brother is in topping up the pressure as required (to make up for the water im letting out).

Eventually, the water that's coming out of the valve I'm bleeding on the radiator starts getting hot, i touch the pipe below the radiator and it too is also getting hot. 'Hooray', says I.

Check the radiator a few minutes later, and it's cold.



I can't get my head around it at all.


I have completely removed the thermostatic valve off the radiator (so in theory, it's stuck on full power) incase that was causing issues, and it hasn't made any difference.

I'm bewildered.


Boiler is still heating every other radiator just fine. Radiator in the sitting room is full of water, and fully bled, but still not getting warm. The pipe, that was getting hot whilst i was bleeding the radiator, has actually gone back to being cool now that I've stopped bleeding it.

I can't make sense of it at all.



Anyone got any ideas?


Cheers

agusta

How much did you open the valve on the opposite side of the thermostatic valve?,With the thermostatic valve head off,can you push the pin up and down?the pin may be stuck closed

DGOBS

Go around the house and turn off all other rads in the house, only leave on the rad thats not heating, turn on the boiler and give it about 10 minutes, check if heating.
Sounds like you have an airlock on the return pipe from that rad.(you may here a good bit of gushing first, this is the airlock moving)
Then go a round and bleed all rads in the house as you turn them back on.

Sorry to update so soon.. turns out it was just the valve on the other side of the radiator... I feel like a tit.

Jacovs

Had similar issue a couple weeks ago. Working in upstairs bathroom so removed the rad. Work done, put rad back on, bleed and heats up.
Go downstairs and notice in passing, the rad downstairs in the hall is ice cold. This wasnt touched. All other rads working fine.
1 or 2 days later after a couple of our regular heating cycles and all rads working perfectly again.
Its like an air lock moved around and somehow worked itself out of the system. No leaks anywhere.