Air lock in open vented system

[Davethomas]

Replaced pump on open vented system.

Potterton boiler downstairs.

Boiler work okay, while heating or hot water demands on as soon the demand is not there boiler will go in to lock out. When pump over run is on burner is off the boiler is bring more heat into the boiler or the air lock.

It's big radiators system about 18 rads, four pipe two for flow and two for return.

I will up load pic soon

 

[Darren Jackson]

Is the pump orientation the correct way round?

 

[Davethomas]

Is the pump orientation the correct way round?

Pump orientation is correct way.

Its potterton gold fsb 30 he boiler without pump overun. As soon the demands is off, zone valves will close and pump stops. Boiler will go into lockout and banging noise from pipework. Red light on boiler will flash.

I have spoken to boiler technical support. They say heat exchanger is big enough to cope with heat. Boiler is under manufacturer warranty. They have recommended installing pump overun kit.

 

[Last Plumber]

Hello.
Need some more information please.

What type of system do you have? It sounds like an S Plan but is it?
Does it have a Bypass installed? If so, what type? (manual or automatic).
Has this issue only occurred since the pump was changed?

In the first post you mention a pump over run but in the second post you say you were advised to install one.
Is there a pump over run installed on your system? If so, is there a route for water to take once the zone valves close? (presuming this is an S Plan).