New pump electrics problem

[Jpsmith]

hello,

I have just fitted a new pump Grundfos alpha1, but it just starts for about 3 seconds and then goes dead as if it has no power.
I plugged the pump directly into the mains and it works fine so I can’t figure out what is wrong.
It is a y plan system with a nest heatlink and thermostat.

Any help would be greatly appreciated as I am pulling my hair out.

James

 

[John.g]

hello,

I have just fitted a new pump Grundfos alpha1, but it just starts for about 3 seconds and then goes dead as if it has no power.
I plugged the pump directly into the mains and it works fine so I can’t figure out what is wrong.
It is a y plan system with a nest heatlink and thermostat.

Any help would be greatly appreciated as I am pulling my hair out.

James

Is the "power 0n" still indicating (lit) even when it appears to be dead.? assuming you have the grundfos alpha1 vs the alpha1 L which requires a app to configure but (whichever model) if it is working OK on the mains then it might point to the output from the nest/thermostat(s), check for voltage from this supply.

 

[Millsy 82]

Is it just on the heating by any chance? Have you got power to orange and grey with hot water off of your 3 way valve?