Biasi M90E no DHW or CH

[PDS]

Hi Guys, called out to a Biasi M90 with no DHW or CH. ignition pcb was faulty but since realised that there is no live to that board. I have a live feed into the main board and fuse is good. Do we reckon it’s the main pcb that’s at fault?

 

[ShaunCorbs]

Overheat stat fine ?

 

[PDS]

Hi Shaun, yes checked as per Biasi instruction.

 

[ShaunCorbs]

Pump running when demand or just totally dead?

 

[PDS]

Pump running but no fan.

 

[ShaunCorbs]

No voltage to fan ?

Check the pump proving circuit

 

[PDS]

No voltage to fan or on the second pcb.

 

[garygvl]

as shaun said is spindle coming out on pump proving and operating the microswitch assembly on the left hand side of the boiler. if you take microswitch off its housing by removing the spring clip then turn on so pump running then push a small screwdriver into the hole to operate the m/switch and boiler fires up you need to change the diaphragm on pump proving assembly

 

[PDS]

I have just checked this and all is working fine. Spindle is free and diaphragm operates correctly.

 

[ShaunCorbs]

Pcb then I would say

 

[PDS]

Thanks Guys. I did think that but thought it was best to confirm.