Which part to replace? (Worcester heatslave 15/19)

[Jakeh83]

Hi I'm hoping for some help, i have the same sort of thudding sound when the boiler switches off now and then and my RCD had tripped a couple ofbtimes although this may be a coincidence, I've eliminated any water pump and valve issues but wondering if its a new motor needed. Regards

 

[oilhead]

Knackered bearings scream persistently, maybe after a little running if the pump shaftseal leaks., not thud. Can you isolate where the thud comes from? If the oil pump solenoid is passing, you may be getting some post ignition. Which model burner do you have?

 

[Jakeh83]

Its a riello rdb its not noisy all the time.

 

[oilhead]

Could be a motor failing. If the pump has leaked along the shaft seal it takes out the bearing. A bad leak could trip RCD's