Pump not working on central heating

[Darren Angel]

I have an open vented system with an oil fired boiler. The zone valve opens for the central heating, boiler fires but pump not working. Have checked inside of pump and the spindle turns freely. I'm thinking elecrical issue. Would changing pump head solve the problem. Thank you in advance for any replies.

 

[ShaunCorbs]

Power to the pump ??

 

[Best]

Check power to pump,
if yes, then try turning speed up, otherwise new pump.
What brand and type is it?
The modern pumps are full of electronics and this causes failures

 

[snowhead]

If it's an older pump you'll be very lucky to get a new head, it'll be a new pump.

 

[Darren Angel]

Its a grundfos 15-60. Not sure if there's power to the pump but its wired via a wiring box which is providing power to the boiler and zone valve. Have tried the pump on all 3 settings.

 

[ShaunCorbs]

You need to prove there's power going to the pump first before doing anything tbh

 

[townfanjon]

Assuming you have power to the pump , if you just want to change the pump head, try to locate a Ravenheat non ERP pump head , it is a grunfoss with a Ravenheat badge .

 

[doitmyself]

Which boiler do you have?

 

[Darren Angel]

Changed the pump head. All worked fine, rads getting hot, then about an hour later, rads cooling down, pump still working, room stat at max. Any ideas gentlemen.

 

[townfanjon]

Changed the pump head. All worked fine, rads getting hot, then about an hour later, rads cooling down, pump still working, room stat at max. Any ideas gentlemen.

Where did you get the pump head from Darren ?

 

[Darren Angel]

Screwfix

 

[Darren Angel]

I had to turn the pump head 180° for the wiring, is it now pumping the wrong way?

 

[moonlight]

Always fit the pump with the arrow facing the way the original one. The head can be removed and turned so better position for wiring.

 

[SavageW]

What boiler do you have? Did you isolate pump via the pump valves or drain the system? Does the pump sound noisey even though the impeller is spinning (if pumps airlocked the sound reminds of the TIE fighters from Starwars )

 

[Darren Angel]

I think there might be a blockage somewhere. Pipes hot from pump down past 2 port valve towards boiler but return pipe from boiler is cold

 

[Darren Angel]

What boiler do you have? Did you isolate pump via the pump valves or drain the system? Does the pump sound noisey even though the impeller is spinning (if pumps airlocked the sound reminds of the TIE fighters from Starwars )

Oil fired boiler. I isolated the pump at the valves, changed the head only. Opened valves, bled all rads and the pump. All was fine for about an hour, then i noticed rads were getting cold. Its not the roomstat, ive bypassed that for now.

 

[moonlight]

Is the feed blocked? And now the boiler is overheating and going to lockout?

 

[Darren Angel]

Shut all upstairs rads, forced heat downstairs, then one by one opened the upstairs again, seems to have worked. will find out in the morning if they all get hot