Baxi 105e won't ignite

[Adam75]

Hi, I've just replaced the diverter valve diaphragms. When trying to restart the boiler for either CH or DHW, the micro switches engage, the pump runs but the boiler does not ignite. The 'Fault on Pump or Low Pressure' light flashes. Have restarted the boiler a few times, still get the flashing light.

Have checked the pump pressure release valve.

There is a little water under the PCB but all looks dry. Have also checked the current on block A4 terminals 3 &4, all ok.

Any ideas, or is it a PCB board?

Thanks

Adam

 

[CBW]

Do you have system water pressure? Is the pump proving switch making?

 

[Adam75]

Yes there is pressure, just under 1 bar.

Sorry what is the pump proving switch?

Both the CH & DHW demand micro switches seem to work correctly

 

[Madrab]

When you manually work (click) either switch does the boiler fire up then? Did water actually get onto the PCB? Pump proving switch is the back one of the 2 micro switches.

Great step through for the 105e diverter here.

 

[Adam75]

Thanks. Doublecheck the pump proofing switch, the pin was coming up and engaging the metal of the proofing switch but not pushing it enough make the switch work.
Then in the metal slightly has temporarily resolved this, I will order the switch.

Still no hot water though, this is definitely engaging but not starting the boiler

 

[CBW]

Still no hot water though, this is definitely engaging but not starting the boiler

Still the dame fault or just nothing?

 

[Adam75]

Same fault for DHW

 

[CBW]

So when you clear the fault, move and engage the pump proving switch manually it still has the same fault?

 

[gas112]

so you now have heating ?
no hot water ?
Is the pin on front of water section facing you coming out and hitting the microswitch when hot tap turned on

 

[Adam75]

so you now have heating ?
no hot water ?
Is the pin on front of water section facing you coming out and hitting the microswitch when hot tap turned on

Yes we have CH but no DHW. The pin is coming out and fully pushing the DHW switch

 

[gas112]

Yes we have CH but no DHW. The pin is coming out and fully pushing the DHW switch

HW demand neon comes on ?
Pump then comes on ?
Is pump proving pin on top hitting the switch or is it not getting high enough

 

[Adam75]

Yes HW light comes on. Pin comes out fully, boiler tries to switch from heating to hot water then the low pressure light comes on.

 

[CBW]

Try operating the pump proving switch and or hot water microswitch when creating a hot water demand

 

[gas112]

you may have put the pump proving diaphragm in upside down also below the diaphragm there is a small hole that can get blocked slightly stopping it working right .Take apart again and clear hole out use the pin on plate thats in there

 

[Adam75]

We went out for a few hours, left the heating running. Came home, tried the hot water without touching the boiler it worked! All works now.