Baxi 105e pump low pressure fault - PCB?

[eddyesi]

Boiler failed tonight, flashing up the pump/low pressure error and pump not kicking in

Checked the PCB and 0V at motor or A4 3&6, so according to the manual its a PCB issue

Took the PCB off and there look like there is slight scorching around one of the solder joints, it looks like its for the relay above the A2 connector, below the large transformer/PS in the middle

Digging around it seems i have the old/original PCB, which is known to have issues with relays, and should get the 5112380 in place.

Going to try this first, as its bloody freezing, if not any other ideas?

 

[eddyesi]

Ok,

confused, got a new pcb and still had the issue, tested the old one again, properly this time, and am getting 230V to the pump, so not the PCB

manual also suggested it could be the primary flow valve, but took that off and seems fine, cant seem to trace it

Anyone got any ideas?

 

[davebgas]

But is the pump spinning? Might be getting 240v but not moving. Does the pump operate the flow switch?

 

[eddyesi]

But is the pump spinning? Might be getting 240v but not moving. Does the pump operate the flow switch?

Yes pump is spinning, put a new head on it already, but its not operating the second microswitch, the front DHW microswitch is ok but not the second one on top, plunger isnt moving. If you manually operate the second switch the boiler fires up for both DHW and CH, but soon as you let go fault flashes up

suspect it may be the diaphragm for the second microswitch (one on top not front), or the plunger. I cant get at it easily so getting a plumber in, as if its not that, need someone to trace the next poss problems.

could a blockage in the heat exchanger cause the issue?

 

[namsag]

If pump is spinning and the top plunger is not coming out to hit the micro switch then its the diaphragm gone
248065 manufacturers number

 

[eddyesi]

Cheers, it was the small diaphragm that had gone, ended up getting a plumber in to sort, as he had the part, it was blood freezing, and boiler needed a service anyway.

All up and running now, just a little lighter in the wallet