water pump issue?

hi all,

the central heating water pump at my parents house seems faulty. it makes unusual noises like gurgling, groaning noises that we never heard before. further to this after just 2 mins in the pump gets very hot and the boiler switches off. the pump itself was originally installed in 1986!! as its the oldest component i am guessing it is that.

the system is a condensing boiler (Worcester bosch 18Ri) with an F&E tank in the loft. the pump itself is SMC comet 130-45 installed 1986 we have NO cylinder

i have done the following to diagnose the system:

Drained F&E tank and refill. all works ok, ball cock works fine. tank drains at a steady rate and also fills at a steady rate.

i have bled all the radiators in the house starting at the bottom. all fine

i have ran a magnet on the pipes in and out of the tank, and around the water pump, no pull on the magnet

i have attempted to diagnose the actual pump, but when i take off the cover, i cannot find any bleed screw

after the above, the pump makes a loud whirring noise when switched on, it runs hot, but does not groan and gurgle. the boiler switches off after 5 mins

i am wondering, or seeking advice what else i can do to get the pump working and ultimately the CH back up working. is it a faulty pump?

previous to this the CH has been running fine. we estimate we stopped using it in may, and last week we put it on to test if the heating was working fine

i will attach some photos.

please note i am not a plumber or CH engineer, i am a DIYer with a splattering of knowledge and experience

many thanks in advance

Pumps gone / cap

You can try testing the cap and then if bad changing the capacitor first if you want

thanks for your quick reply shaun. how can i be sure its not an airlock issue? i don't mind changing the pump, its served us well! but it will be pointless having a new pump if i there are outstanding issues.

Have you drained the system?

ShaunCorbs said:

Have you drained the system?

Click to expand...

hi shaun, yes, i drained the system to check for any cold feed blockages on the F&E tank. there was no issues. it drained and filled up at a steady rate

Did you fully drain the system or until you heard the tank running ?

Hi Shaun, I was actually up in the loft. I watched the tank drain all the way , and watched fill back up, if that’s what you mean, thanks

hi all update:

i drained the tank in the loft and all the radiators today. i then went through the bleeding process once the water was reinstated. there was no issues with the tank re-filling and the ball valve closing the water. after the whole process. i attempted the central heating and same result. the boiler lasted 2 mins and shut off. the pump was not making excessive noise but it didn't "sound" right. whole process took me 2.5 hours.

any suggestions?

thanks

Turn the hot water on only and the boiler temp to min and let it run

ShaunCorbs said:

Turn the hot water on only and the boiler temp to min and let it run

Click to expand...

hi Shaun just a reminder that this is a condensing boiler not a combi. the boiler is for the central heating only. however, do you still want me to try?

thanks