Underfloor Heating Pump goes into a blocked error (Grundfos UPM3)

[howdoyousaynejc]

Hi all!

Went to stick the underfloor heating on and the pump started making a weird noise and the first red LED and the last amber LED are on - which per instructions means that the pump is blocked and it is necessary to deblock the shaft. It has a deblocking screw in the centre of the control box so I push it down and turned it counter-clockwise multiple times and I can hear it turning so the shaft shouldn't be blocked. But when I turn the system back on it goes into the same error mode.
I even tried to give it a a few love taps with a rubber hammer - anything else I can do, besides calling the engineer to have a look?

The pump is also a new one having been installed back in March this year, so I doubt any sludge is in the pump yet.
Worth mentioning that this is the first time we have switched the heating on for at least 5 months.

 

[ShaunCorbs]

Did you love tap the screwdriver?

 

[Pat Dear]

I've tried using the screw driver but it didn't work, more advice please?

 

[ShaunCorbs]

Need to split the pump and clean the ball

 

[Andrew365]

I have exactly the same issue. Have you resolved yours yet?

 

[Jon Eastcombe]

I had the same issue. I found the anti clockwise turn alone wouldn’t clear it. I isolated the flow and return, switched off the power and then tapped the screwdriver with a hammer whilst turning. I then switched it on with the flow and return still off and it started again. Then turned the flow and return on and all working.

 

[Russell S]

I had the same issue. I found the anti clockwise turn alone wouldn’t clear it. I isolated the flow and return, switched off the power and then tapped the screwdriver with a hammer whilst turning. I then switched it on with the flow and return still off and it started again. Then turned the flow and return on and all working.

I had the same issue. Tried turning anti clockwise multiple times but it didn’t work. Then found Jon’s advice, tried that and it worked first time. Thank you Jon!