Vokera Compact HE 29 - Brainstorm help needed

[ShaunJUK]

Boiler problem. Managed to get from an NTC fault but now have an APS fault.

So far boiler has new PCB, Fan, NTC sensor, Pressure Differential Switch and Air Pressure Switch.

Followed flow chart. PCB control outputs ok. Getting 22v from 8.3 - 8.5 but not getting 24v to Fan so fan isn't spinning.

I am thinking new PCB faulty?

 

[ShaunJUK]

Just to add. Flowchart states replace cabling and connections however I have fully tested the cabling with a multimeter and everything is fine. NTC is showing expected resistance when cold.

 

[ShaunJUK]

All fixed. PCB was faulty and APS had been connected incorrectly.

 

[vulcancontinental]

If problem comes back get a GAS SAFE engineer to clean the negative venturi spotless or replace.