Worcester 24 CDI

[lee1976]

Hi i have been to a job today the problem is when the boiler is on DHW or C/H within 5 sec of turning the boiler on the 2amp fuse in the PCB blows.!!
I have gone though around 6/7 now.
My first thought was that the fan was faulty but i have changed it but still the same problem.......
second thought maybe the pump as the pump and fan are the only high voltage items all the rest are low voltage...but the pump is running fine..
CAN ANY ONE PLEASE HELP
CHEERS

 

[gas4you]

gas valve opening? solenoid fault?

 

[lee1976]

it can not be that becouse its low voltage the fault must be on either the fan or pump i would have thought also thought board was damp but warmed it though still the same problem

 

[Rob]

the fault must be on either the fan or pump

you've changed the fan...

 

[scatmanjohn]

What part of the start up/ignition sequence is it getting to.

demand...pump running....fan running...aps made....ignition sequence..etc

 

[lee1976]

pump running.... aps ok.....fan starts to run then the fuse explodes does not get to ignition?????????

 

[ChrisR]

Try with the GV disconnected. Not logical at low voltage , sure, but something isn't logical here!

 

[gas4you]

have you checked condition of wires to fan? Are they shorting somewhere?

 

[lee1976]

Try with the GV disconnected. Not logical at low voltage , sure, but something isn't logical here!

 

[lee1976]

have you checked condition of wires to fan? Are they shorting somewhere?

Checked wires all seem fine got continuity and all wires fully insulated....when the fuse blows it really does go with a bang it's not just poping

 

[Softus]

...but the pump is running fine...

This doesn't mean that it's not the pump, but it sounds more like PCB fault.