I was asked by a plumbing/heating firm to investigate a boiler.
Thy had changed the PCB (a very expensive item) and the fault remained.
Boiler tried to fire but shut down after a few seconds if I recall correctly.
As I remember it basically I discovered that a microswitch switch over depending on flue pressure. The thing had a lot of snow in it - it was an exeptionally bad year for snow - it had ruined the microswitch. I one position it put the fan on and once pressure was correct it changed over and ran the boiler. Snow had got in and ruined the microwsitch so all three contacts made. I changed that microswitch and all was well.
I was asked by a plumbing/heating firm to investigate a boiler.
Thy had changed the PCB (a very expensive item) and the fault remained.
Boiler tried to fire but shut down after a few seconds if I recall correctly.
As I remember it basically I discovered that a microswitch switch over depending on flue pressure. The thing had a lot of snow in it - it was an exeptionally bad year for snow - it had ruined the microswitch. I one position it put the fan on and once pressure was correct it changed over and ran the boiler. Snow had got in and ruined the microwsitch so all three contacts made. I changed that microswitch and all was well.
