Boiler Not Working

3 Month ago, i changed the wax converter, on my Potterton 100 combi boiler. Since then it has worked fine, till this week.
Sunday, switched on the boiler, and it blew the internal fuse. It is a ceramic fuse, 2 amp. I put in a peice of fuse wire, and re-started the boiler,
the presure guage, on the fill loop, was reading just in the green, after 10, maybe 15 seconds of running, the needle went passed the normal position, and into the red at the opposite end of the clock. the boiler then cut out, and air not steam, came out of the top air vent. also water, and steam came out of the drain pipe ! could it be the pump, or the expansion vessel.
Any help would be much appretiated

Pump most likely. Check there is power to it and use the black cap on the front to try and turn the impellar. It maybe seized or just wearing out. If so just replace it.

I have removed the pump, started the system and the propeller is not turning... there is electric to it, as I got a belt from the wires when removing it. I realise this is not the proper way of checking the pump. anyone tell me the proper way to check it?

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Foolish post removed

Mod Rupert

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best to get someone in before you damage yourself and your boiler IIMO

I wonder how many DIYers get killed each year. Must be a few hundred.