Bleding and zones

[plumbinguser]

When bleeding the radiators it is recomended to turn the boiler off to prevent air being drawn in (can't see how if the system is at 1.5 bar).

If the boiler and zones are off then would it bleed ok or do I have to ensure that the zone valve is on whilst the boiler is off?

 

[stevetheplumber]

When bleeding the radiators it is recomended to turn the boiler off to prevent air being drawn in (can't see how if the system is at 1.5 bar).

If the boiler and zones are off then would it bleed ok or do I have to ensure that the zone valve is on whilst the boiler is off?

manually open all zone valves

 

[Puddle]

When bleeding the radiators it is recomended to turn the boiler off to prevent air being drawn in (can't see how if the system is at 1.5 bar).

We are not turning the boiler off to stop air being drawn in ,it is the pump we are turning off,this is more important on open vented systems,were if rad on pull sit on pump this will happen,agreed on sealed ,pressure systems this will not happen,however we turn boiler off to protect it ,incase when you bleed rads the pressure gets to low,as you are letting pressure out to vent,so turn off and vent,refill and turn back on,if you vent system when hot turn off take note of pressure in system,maybe 2.1 bar,vent rad and fill back up to that point as when system cold will go back down

If the boiler and zones are off then would it bleed ok or do I have to ensure that the zone valve is on whilst the boiler is off?

If you are venting rad only there is not need to open zone valve ,if you are venting pipework and rad open zone valve so water can fill pipework upstream of valve

 

[plumbinguser]

Thank you both, it's only the radiator so I'll leave it all off