Vaillant Pump Replacement

[JimM169]

The pump on our Vaillant Eco Tec 637 boiler has finally given up, I had to manually spin the shaft to get it to fire up yesterday but when I tried that today it's started to trip the RCD in the CU. I've measured the resistance across the L and N and it's reading in the Mega Ohms so pretty sure it's dead.

A genuine pump assembly is knocking on the door of £300 but a replacement is a much more reasonable £126 or just a replacement pump head itself can be had for £70

https://nationalboilerspares.co.uk/product/vaillan...

Swapping out the pump head looks to be the easiest (4 bolts and it's out) and cheapest but before I do is there any reason why I should swap the whole assembly instead?

Thanks

[GasEngineer]

Swapping just the head is what most heating engineers will do.

[JimM169]

GasEngineer said:

Swapping just the head is what most heating engineers will do.

Great I'll crack on with a pump head only then, although realised the one I linked to probably isn't going to work as need a 5 wire connector and that looks to only be 2!