Gloworm Boiler locks out when both CH and HW are asked for.

I have a 7 year old Gloworm Ultimate boiler. When the boiler starts in the morning, I have it set to provide both HW and CH. After about 5 minutes, when the water temp in the boiler is only lukewarm, the high limit stat kicks in and disables the boiler. I have to wait for a couple of minutes before it will allow me to re-set it. It then simply repeats the cycle.

When I run the boiler with only CH asked for, it works fine. When I run with HW asked for, it kicks in the stat again.

I did have a problem with the motorized valve actuator, but replaced this and it is working fine but I don't think it has to do with this anyway.

Any ideas would be helpful.

Thanks

the pipe going intot the top of the cylinder is airlocked

Thanks Bradley

Is this the hot water storage cylinder?

Any ideas on how to remove the airlock?

The upper pipe going from the boiler into the side of the hw cylinder normally has a bleed point on it. I'm not so sure that's going to cure your problem entirely though.

Thanks Chris.

The pipes going out from the top of the boiler are boxed in (and decorated.) Anyway I might be able to bleed it nearer the tank? I think the air is circulating through the pump as I can sometimes hear a swooshing noise about 10 minutes after the boiler is switched on in the morning. Would a photograph of the set up at hot water cylinder help?

Antartica? I guess being able to repair your Central Heating is a pre-requisite down there - even in the Summer.

The bleed point will be at the hw cylinder end. Look on the upper pipe of the two which go into the side.

Don't tell anyone but I'm a penguin.