One cold radiator

Hi all

I've replaced the y plan valve on my system and now I have heating again no problems every radiator works apart from one downstairs.

Ive tried turning the locksheild off and trvs to 0 and then just leaving that one on and it just about gets aired. I then reopened them locksheild just cranked open a turn and a half and trvs 3 upstairs 2 down stairs they all get hot again but the offending radiator still won't get hot and even loses it's tepid temperature when I re opened the rest of the radiators on the system

Checked the trv and locksheild working fine on the radiator aswell

Can anyone shed aft light I'm out of ideas

So if all the other rads are shut off, does this one get hot at all? Have you made sure the TRV and lockshield on the problem rad are fully open when you test?

I think you are opening the other lockshields too far and possibly robbing heat from this rad. Try to get this rad hot on its own first then gradually introduce the others but open the lockshields a minimum amount.

Look up the FAQs on balancing radiators.

Yes done the above made sure it got hot and then only cranked them open a bit not full just slightly open.

Trv moves freely on the pin and locksheild has opened slightly and the cold radiator will get hot but still doesn't come warm when I turn the others slightly open

Ok, so open this rad's lockshield fully, let it get hot, then open the others gradually so you get a balanced flow to all.

Not the most scientific way of balancing rads but it might work in this instance.