Y plan refilling problem (airlocking)

[tom0]

Hi all - hope someone can help.

I have a Y plan system that I have drained the CH to replace bathroom rad with towel warmer.

When refilled I have bleed the rads and mid position valve then tested. The boiler (british gas 330) raises the temp quickly and shuts off but the pump remains on. The pipes on either side of the mid position valve are different temps and bleeding it doesn't change anything, suspect airlock around here.

Have tried back filling from cold mains, turning all rads off bar one and running and turned the pump around, all without success.

The only thing I didn't do was set the mid position valve to "man" when draining and refilling. Could this be the problem?

Any other advice would be appreciated.

Cheers

 

[Slugbabydotcom]

Between the 3 way valve and the cylinder there should be a vent. Have you bled the air from it?

 

[gasgeezer]

the boiler is fairly new prob still in warranty it has a pump over-run test that or get b.g back to sort it

 

[tom0]

Between the 3 way valve and the cylinder there should be a vent. Have you bled the air from it?

yup, several times

Does having the valve set to man make a big difference?

Cheers

 

[tom0]

the boiler is fairly new prob still in warranty it has a pump over-run test that or get b.g back to sort it

Thanks for the prompt response but i'm fairly sure it is air as i can hear it but cannot shift it. I'm sure the airlock is around the port valve but the bleed valve just produces water. Tried closing all rads bar one and turning the pump around. Any ideas?

Cheers

 

[chrishutt]

Return 3 port valve to auto position, set system for HW only, then see if you can clear air from just the boiler and that circuit. Does the boiler have an air vent in it? It may be automatic, but check that cap on top is loose and letting air escape.

 

[tom0]

Return 3 port valve to auto position, set system for HW only, then see if you can clear air from just the boiler and that circuit. Does the boiler have an air vent in it? It may be automatic, but check that cap on top is loose and letting air escape.

Thanks for the help.

The boiler doesn't have a bleed valve but has drain valves on the circuits where they enter the boiler. Suspected the air was around the boiler so in desperation I tried flushing the circuits out by back filling and opening the drain valves at the same time. Improved the situation cos the temp didn't rise as quick. Got heat to one side of the rads before boiler cut out and noticed the temp difference between the pipes at either side of the mid position valve. Tried bleeding this several times without success.

Any ideas?

Cheers

 

[chrishutt]

Any ideas?

Try what I just suggested?

 

[tom0]

Any ideas?

Try what I just suggested?

Will do - cheers