lockshield valve with bleed screw

[crooner]

hi, can someone please take a look at this image of this radiator valve ,it's at the bottom right of radiator the TRV is at the TOP left of radiator , have had problems with this radiator heating up,
finally an engineer got it going said he cleared an air lock at bottom valve ,
it's back to being cold again , what i want to know is can i simply treat the the screw that is between the side of the radiator & the lockshield shut off ( see image ) as a bleed screw to clear it again & hopefully get it heating up again

 

[terryplumb]

Not likely to do anything other than let water out. Have you got air in top of rad , have you bled the rad from the bleed screw at the top of rad ?

 

[crooner]

yes , top of rad has been bled

 

[terryplumb]

Remove the trv head ,and ensure the pin in the centre of the valve body ( not the removed head ) is free to move up and down a couple of mm. This is to determine if the trv is letting hot water into the rad .

 

[crooner]

Trv free to move has recently been replaced

 

[crooner]

Would it be safe to unscrew that bleed screw on the lockshield to see if there is any air in the rad .if so wont get a chance to do that till next week

 

[terryplumb]

It looks more like a drain cock to me. If you decide to open it ,only do so 1/4 turn at a time ,and be prepared for water to come out .air will not naturally collect at the bottom , your rad is full of water. If your engineer told you he had shifted an air lock ,it will have been in the pipe run ,not the radiator.any air getting into the radiator will rise to the top ,that's why the air bleed valve is situated there.

 

[shambolic]

That’s a drain to drain water out the leg. Normally used on a drop feed system.

 

[crooner]

thanks terryplumb, shambolic agrees with you that its a drain cock , i didn't think it was because there was no drain to attach a hose , still seems to be a air lock problem , will have to get him back again , posted this thinking i could simply get the air out with that screw , thanks to you both for your help

 

[terryplumb]

Worth trying yourself mate .something you could try ....turn off trvs on every other rad in property ,with central heating on. See if rad now works. I assume you have a gravity fed c/ heating system ,as opposed to a combi / pressurised system. Just being nosey ,the above can be tried with all of them.

 

[shambolic]

The valve is actually upside down.
You put a bowl under it and partially unscrew using a bleed key then fit hose over the end of it.

 

[shambolic]

Sorry not upside down but 90deg out if you know what I mean judging by your photo.

 

[crooner]

Will have another look at it next week
just wish i was there when the heating engineer cleared the air lock ,