Faulty boiler

[Connor Williams]

Hello, I am having problems with a Worcester Greenstar si boiler, the hot water works fine but the boiler instantly switches off when I turn on the heating.
The pump is working and there is no air in the system and there is no room stat.
The flow pipe coming out of the bottom of the boiler is hot for about 10inches down the pipe and then is cold,I doubt its an airlock, could this be a faulty diverter valve? Many thanks.

Connor

 

[nzmanc]

Airlocked?

 

[REDSAW]

had the same symptoms a few months ago on a wb.
is it a new install or was it working fine before in its current situ?.

 

[Connor Williams]

Hello thanks for your reply,the boiler was fitted four years ago and was apparently working okay before the summer.
I have vented all the rads,pump and air valve several times, each time the boiler would shut down I would keep venting but no air was present.
The pump seems to be working but the flow pipe will get hot about a foot down its length and then is cold, I cant understand why the water will not pump round the system.
I can only assume the boiler has a faulty diverter valve but how difficult are these valves to purchase and install on a Greenstar Si boiler?