2 rads upstairs and 2 rads downstairs not working

[omegaman]

Hi,

Drained down heating system yesterday to work on a couple of pipes and filled system to 1 bar (cold) and bled the rads. Turned the heating on and 2 rads upstairs and two downstairs didnt get hot. The furthest rads upstairs and downstairs are hot. On one of the upstairs rads, pipes leading to the rad is cold and on one downstairs rad the valve is hot but rad isnt.

The rads dont have TRV's on them, just open/shut control valves and lockshields. Boiler is a system boiler with pump/expansion vessel built in (cant remember the make) and stored hot water is vented.

I've read the FAQ a few times and searched on the net but havent come across a similar problem.

Hope you guys can help.

 

[omegaman]

anyone want to at least hazard a guess?

 

[electronicsuk]

Air lock, most likely, unless you have either altered the TRVs or somehow made a mistake with the pipework. Try the usual process of closing off the valves on all rads except one of those that is affected, and see if it starts to warm up. Repeat as necessary for each affected radiator.

EDIT: Pump may also need bleeding?

 

[BingoBongo]

check the motorised valve is open

is there a vent on top of the boiler/cylinder?

 

[omegaman]

Thanks, I'll give that a go. Should I open the vent on the rad while doing this to get the air out?

I do actually remember turning one valve off because there was a leak on a nut and I forgot to turn it back it on. Thats now sorted. The other pipes/valves are untouched.

Motorised valve is open and the heating system is sealed.

 

[twgas]

filled system to 1 bar (cold) and bled the rads.

did you then check the pressure (I know, it's obvious but a lot of people forget to check it after they've bled the rads)

 

[omegaman]

Yes, I did.

 

[electronicsuk]

Thanks, I'll give that a go. Should I open the vent on the rad while doing this to get the air out?

No, although if you get some heat through then you can bleed the air out later, as some will inevitably collect in the radiator if there is an air lock in the system.

Make sure you take a note of how far open the lockshield valves are open on each radiator before you close them off, as it will save time balancing later on.