Do I bleed radiators in a sealed system with it hot or cold?

[Mutley56]

Hi there. In a sealed system, does the ch system need to be cold before bleeding the radiators or should the system be hot? The boiler controls will be switched off just before bleeding to ensure pump will not start up. I have a system boiler and there is air bubbling in an upstairs radiator after system was drained and refilled to allow some pipe repair work. Inhibitor was added and I have checked the air expelled with a lit match and it doesn't pop and so it probably isn't hydrogen.

Thanks in advance for your advice.

Mutley56

 

[Richardthe3rd]

Always bleed a sealed system when it's cold, do it when it's hot you'll get a inaccurate reading as you're reading it as expanded hot water.

PS. You know I'm amazed that no 'so called expert' has answered your question, this forum is full of 'knowitalls', that know jack about the subject...........

 

[Mutley56]

Thank you

 

[sooey]

Obviously such a technical question needs a 'master' like yourself to do it justice dick.

 

[Richardthe3rd]

Obviously such a technical question needs a 'master' like yourself to do it justice dick.

That goes without saying la!!