ch pump very hot rads downstairs cold

[todaystrouble]

I have a Grundfos 15-50 pump - when central heating turned on gets extremely hot and pipe around pump are all hot.

However rads downstairs are cold, rads upstairs are hot.

I have flushed all rads downstairs with water to remove sludge etc. but still rads do not get hot. Have tried turning off upstairs rads to no avail. Have bled rads until hot water comes out but heat is not retained in rad.

Only advantage is spending most of time in bedroom??

any ideas help please

 

[mackandmutley]

I think the regulars on here would suggest the pump at fault and to check it is turning, they did with me when I asked a very similiar question.

 

[seco services]

if you drained the system etc check pump is not airlocked and is working.

 

[Slugbabydotcom]

Sometimes the armature will spin making you think the pump works but how do you know the impeller is still attached to the other end of the armature?
With isolation valves turned off its time to undo the 4 allen bolts and have a look inside the pump

 

[todaystrouble]

Many thanks for the info, not sure how to tackle the pump so may have to get a superior brain