Strange Central Heating / Radiators issues

[fixitflav]

I've a feeling that pump is faulty or the impeller & maybe the pump ports are full of sludge, I would switch off the boiler, shut the isol valves on either side of the pump, remove the four stud bolts from the pump and lever it up & out carefully, inspect for sludge build up in the pump ports, get a tie wrap and push it through each impeller vane to prove clear.

Agreed, I had a problem a few years ago. Had a slight kettling noise when system hot. Didn't suspect the pump but eventually it started to vibrate badly, so I replaced it (a stainless disc at the eye of the imperller had come adrift). The new pump cured the noise completely and when I looked into the old one, the impeller, 2 discs about 2mm apart, was solid with crud.
But OP - be careful releasing the water when you dismantle it. I did something similar on an earlier occsasion, can't remember the details but I got water in the junction box somehow and the RCD kept tripping. I had to set up a hairdrier on it for an hour or 2 to cure it.

 

[scotthud]

ok done that it went from 22W to 20W

 

[Johntheo5]

There is definitely something up with that pump, 20/22W on CP2 means the pump theoretically anyway is pumping nothing but it must be circulating something if the HW cylinder & (some) rads are heating up?, I would remove the pump head as suggested above.

Just confirm that this is your pump, a 6M.

 

[scotthud]

Looks the same this is mine.

 

[Johntheo5]

Well, you will have to check out the condition of that pump, I would remove the head and inspect it before throwing a new pump at it, how old is it?

 

[scotthud]

a few years now it was swapped from the original pump awhile back by British Gas, when it gets warm, ill have a look at taking pump off, unless it goes to crap before, what sort of pump should i be looking at to replace this one with at some point, 14 Radiators 6 up 8 down.

 

[Johntheo5]

6M Dab Evosta 3 which also displays the flowrate as well as the power. OR like my own, a 6M Wilo Yonos Pico, probably a bit cheaper but a very nice quiet pump, mine is 5 years old.

 

[scotthud]

Thanks ill take a look.
is this them?

Wilo Yonos PICO 25/1-6-130 Glandless Circulating Pump 230V - Screwfix

Order online at Screwfix.com. Easy installation and set-up, accessible through 'Green Button Technology'. High energy performance is achieved through the proven EC motor technology and precise setting in 0.1m steps. Longer de-blocking routine can be activated manually. Error code indication for...

www.screwfix.com

DAB Evosta3 Circulating Pump 60/130

• Suitable for heating and air conditioning systems• Covers 4, 5 and 6m head pumps in one model• High efficiency motor• IPX5 protection against water damage• Air vent plug for releasing trapped air and shaft access• Digital display• Quick coupling electrical connection can use other...

www.toolstation.com

 

[Johntheo5]

Yes, the DAB is very good price.