overheating boiler

[chunky789]

Hello everyone.
My old boiler (not the wife) is overheating. It is a glow worm econony, approx 15 years old running 8 radiators. is it possible that the internal thermostat is faulty, and can it be replaced. I have replaced the correct pump according to the suppliers spec.
Any ideas or solutions,Thanks in advance.

 

[ChrisR]

Did you open the pump valves?
Does the pump sound too quiet - if so unjam through screw in end.
Does it sound like there are bubbles in water - try bleeding pump and venting at all points , there is often a vent point near HW cylinder.

What work have you done - why/when did you change the pump?
Yes you will still be able to get the thermostat.

 

[chunky789]

Hello chrisr, thanks for replying. pump valves are open enough, pump is set to 3 and is working ok. No bubbles in the water. The pump has been bled and vented.
The pump was replaced 2 years ago because it was weak. It did improve but didnt stop the banging. I was advised to turn down the gas pressure, which a plumber did.
Just had a disater and stripped the thread on the pump valve screw cap, must replace now. I will check any replies and follow any advice when I have replaced the pump, thanks.

 

[ChrisR]

That's a bummer, never heard of that - what make of pump was it? Did have a pump valve come apart the other day though. Leaking from the joint on the shaft so I did it...apart!

If your rads ARE getting hot then yes the stat's suspect, if not then sludge could be the culprit.

Old GW's are noisy though!

 

[chunky789]

Managed to fix thread without replacing the pump. I checked the pump valves and the bottom one opened a bit more, The system has been on for over an hour and no banging yet when there was before, so fingers crossed. Thanks ChisR for your help.