Boiler gets very high pressure, and cuts off

[jim.allwood]

Hi,

I have a boiler that has not been used for about 6 months. The system had been drained until yesterday, when I filled it back up.

I bled all the rads, no problems, no leaks. But when I try to run some hot water or turn on the heating the boiler fires up perfectly, then the pressure rises dramatically within seconds, and the boiler goes off, reset button pops up.

I know there is not blockages as the water ran to the rads fine and water comes out when I turn a hot tap on.

I pressured the system up to about 1 bar.

Any ideas?

Thanks in advance.

 

[archiedale]

check iso valves below boiler

 

[jim.allwood]

Hi, yes, that my first thought, but they are all open.

 

[dontknowitall]

Is the filling loop letting by? I'm not too hot on boilers though!!

 

[jim.allwood]

No, I disconnected it after I'd pressurised the system. That would have made sense though.

 

[Billy Bob Bob]

sounds like pump has failed/jammed

 

[jim.allwood]

Yeah, that sounds like a possibility, it gets red hot. How can I test it? Thanks

 

[Billy Bob Bob]

power off centre screw out be prepared for some water,try spinning the pump,you may un stick it,if not can you use a multi meter?

 

[jim.allwood]

OK, I'll give it a go. I'll get back let you know in the morning. Yes, I can use a multimeter. Many thanks.

 

[jim.allwood]

Ok, so I couldn't resist waiting, and you were spot on. It was jammed. A quick fettle with a screwdriver, and she spins freely. Boiler fires up, and stays on. Problem solved. Thanks very much. Now I notice though that the relief valve is slowly dripping water, so I guess it maybe faulty, I'll investigate a replacement in the morning.

Anyway, thanks for your help.

 

[Billy Bob Bob]

Ok, so I couldn't resist waiting, and you were spot on. It was jammed. A quick fettle with a screwdriver, and she spins freely. Boiler fires up, and stays on. Problem solved. Thanks very much. Now I notice though that the relief valve is slowly dripping water, so I guess it maybe faulty, I'll investigate a replacement in the morning.

Anyway, thanks for your help.

could be just the prv faulty BUT...be aware you could have a faulty filling loop or expansion vessel causing this