Radiator valve stuck closed (Not TRV)...

[GaryTG]

Hi, I would appreciate a little help.

I am unlucky enough to have an 8mm microbore gravity fed indirect central heating system (11 Radiators) on a 30 year old free-standing floor boiler. The radiator valve/lockshield are the twin entry type (8mm).

All the radiators are fine except for two: a small upstairs bathroom radiator and a large hallway radiator. I have tried to fix the small upstairs radiator without success. I bunged the F&E tank and cleaned it out for the first time in about 45 years! (and yes, I did refill and un-bung it afterwards!)

I tried bleeding the upstairs radiator without success. It has been cold for some years now. I thought the likely fault was an airlock. So I ran the system and then turned BOTH the lockshield and the manual (non-TRV) off. I tried to depressurise the radiator but there was no pressure to release. I then switched the boiler off.

Next I opened the lockshield and bled the system: Only water and no air came out. The water was warm. So far so good.

Next I closed the lockshield and opened the radiator valve: no water no air...nothing.

As far as I can see, this should have forced any airlock on the flow side out through the radiator. But there was nothing at all.

My best (amateur) guess now is that the radiator valve is stuck closed (even though the tap top appears to undo properly).....or there is a huge airlock!

Any ideas/help? Can I try freeing the radiator valve with WD40? I have looked online and everyone and their dog tells me how to fix a stuck radiator valve....but only if it is a TRV.

Thanks in advance......

 

[ShaunCorbs]

Sounds like the pipe could be blocked which normally happened with them

 

[GaryTG]

Sounds like the pipe could be blocked which normally happened with them

Ahh yes. The radiator internal pipe (director/spreader? not sure about the proper name). That pipe is VERY narrow AND it could dip into the crud in the bottom of the radiator....I agree a prime candidate.....particularly for the long radiator.

 

[GaryTG]

Sounds like the pipe could be blocked which normally happened with them

And if it's blocked in the 8mm feed....I don't even know where the manifold is..... double Grrrrrr

 

[Roy_66]

And if it's blocked in the 8mm feed....I don't even know where the manifold is..... double Grrrrrr

Hi Gary,

Sounds like you might be at a point to get a good professional in.

If you want to carry on could you remove the radiator, take it outside, connect it to hose and blast it clean (video prob avail).

Also flush the system in the house, making up some bits of scrap where the rad should be to go into a bucket. Guess you might need to pressurise the system up.

Sounds a professional job, but if you have the time and energy you will get satisfaction from sorting it.

Cheers,

Roy (very amateur plumber with 10mm connections, and I do use professionals)

 

[GaryTG]

Hi Gary,

Sounds like you might be at a point to get a good professional in.

If you want to carry on could you remove the radiator, take it outside, connect it to hose and blast it clean (video prob avail).

Also flush the system in the house, making up some bits of scrap where the rad should be to go into a bucket. Guess you might need to pressurise the system up.

Sounds a professional job, but if you have the time and energy you will get satisfaction from sorting it.

Cheers,

Roy (very amateur plumber with 10mm connections, and I do use professionals)

Just colour me "confused". I said I got no air or water out when bleeding one side. But this morning, as if by magic, this very small radiator was working again.

I don't understand why....unless I moved the airlock or got rid of just enough of it for the radiator work again.

So I tried doing exactly the same for the other much bigger (downstairs) radiator. This one is much bigger (about 1.5m long). I tried the method twice but so far no luck. I'll see what tomorrow brings after the system has stopped, settled and restarted in the morning.

I'm not convinced I know what has happened but 50% of my problem appears to be fixed......and I've got a nice clean F&E tank with a new home made cover to keep it clean!

 

[Roy_66]

Just colour me "confused". I said I got no air or water out when bleeding one side. But this morning, as if by magic, this very small radiator was working again.

I don't understand why....unless I moved the airlock or got rid of just enough of it for the radiator work again.

So I tried doing exactly the same for the other much bigger (downstairs) radiator. This one is much bigger (about 1.5m long). I tried the method twice but so far no luck. I'll see what tomorrow brings after the system has stopped, settled and restarted in the morning.

I'm not convinced I know what has happened but 50% of my problem appears to be fixed......and I've got a nice clean F&E tank with a new home made cover to keep it clean!

Perhaps the gunge had shifted. Do you put corrosion inhibitor in your system?

Cheers,

Roy

 

[GaryTG]

Perhaps the gunge had shifted. Do you put corrosion inhibitor in your system?

Cheers,

Roy

Yes perhaps it has moved it. As for inhibitor......er......I don't know if there is any in it. Whatever I have bled out was clear, clean....so probably no inhibitor (assuming I would see some colour). The system hasn't been drained for decades.....

I've just been round all the downstairs radiators...and there is no drain tap (?). There is a drain tap on the boiler but it is about 9" higher than where a radiator drain tap would be. I suppose I could add the inhibitor to the F&E tank and then draw it in by draining from the boiler....

I just know I hate microbore....especially the 8mm variety.