Cold radiator (airlock?)

[Bitpipe]

We have 3 towel rads (Zenhder) in the three bathrooms on first floor - only rads in the house and are on their own circuit.

 

Two are hot, one is cold - has been like this since commissioning. Plumber suspected that it was air-locked and  came out and 'fixed' it but it didn't last. 

 

I've tried bleeding, there is an initial release of air / water but then it slows to a trickle and then nothing.

 

I've tried turning other two off and running pump - it eventually heats up and releases a little bit more air when bled but as soon as the other two are opened up again it goes cold.

 

Have asked plumber to come back, but while I wait any suggestions on resolving this?

 

Thanks.

 

[PeterW]

Is it a pressurised system..? What is the pressure set at..?

[Bitpipe]

21 hours ago, PeterW said:

Is it a pressurised system..? What is the pressure set at..?

 

Yes, and I'd forgotten to recharge the vessel after the initial round of bleeding. It doesn't have a gauge but charging it up seemed to do the trick.

 

Thanks Peter!

 

[PeterW]

It's sometimes the simple things ....!!