boiler going off after short time

[herculesms16]

hi all...

I have an old gloworm 52 b boiler that I plan on changing next year but would like to get another winter out of her. I am running a wilo gold 50 pump on it.

I had a problem last winter with the boiler going totally out after it has been fired up for about 10 minutes. I put some anti sludge stuff in there ran it and drained it down then refilled. This got me through last winter but the problem has come back. I have drained and refilled now twice but the problem is still there.

This led me to think an air lock or pump issue. I have bled all radiators after filling up and cant get any more air out of system. I read a bit today and looked deeper into the pump.

I removed the screw at the rear to gain access to the impeller shaft and it is very free with some forwards backwards float. It comes on and changes speed accordingly so I am thinking the pump is ok....unless it is too free and the impeller is goosed.

How much resistance should there be on the pump when isolated and turned with a terminal screwdriver? I can easily finger and thumb it......

Im at a loss and am almost ready to bite the bullet and buy a replacement just to rule it out.

any help greatly appreciated...

also the pilot goes off too......would this be normal in an overheat lockout situation?

thanks

 

[Agile]

Without proper information on flow and return temperatures I cannot give you any suggestions.

Your pump sounds fine but removing the head and doing the finger test would confirm that. See FAQ.

Old boilers are protected on overheat by cutting the pilot light.

Tony

 

[45yearsagasman]

Your old boiler does not have overheat protection if I remember correctly.
The pilot going out is a gas related fault and nothing to do with pumps.
Get the boiler properly serviced and the pilot fault can be rectified.

 

[JohnD]

edited

my mistake

 

[herculesms16]

cheers for the replies...

I have had the pump split now and it seems fine apart from some float which I believe is normal. I need a rag to stop the impeller by hand on highest setting. bearings fine with no play or hint of seizure..... impeller fine..

It just had a good run and got all rads hot then cut out completely(including taking out pilot) as you'd expect in an overheat situation. It will then not stay on for more than a few seconds until it has cooled down!!!

I thought all boilers had to have some protection for overheating as i know from working on large scale industrial boilers that they can blow up with devastating consequences. but I aint a plumber so what would i know!!

I can still hear some air rushing through system at the pump so am wondering if there is a repeating air lock but cant get it out....well not through the rads anyhow as ive bled them all with no escaping air.....does this sound plausable?

perhaps time to give up and call someone in...just like to do thing myself.
cheers all and any other ideas welcomed

 

[45yearsagasman]

FFS I don't know why I bother to post if advice is ignored. IF THE PILOT GOES OUT ON YOUR BOILER IT IS A GAS FAULT AND FA TO DO WITH THE PUMP. GLOWORM 52 HAS NO O/H PROTECTION.
There, I feel better now, I think