The pwm or (demand/speed control) signals are very difficult to measure on this appliance using standard equipment.
The voltage change from standby to demand is very small and only happens once each time the appliance has been powered up and a demand created. This is why it is extremely important to follow the test in XSol carefully as the voltage increase is easily missed.
The fan connector must be removed from the fan so the voltage change is not masked but the harness must be connected to the PCB otherwise the voltage change cannot be seen.
This test is bespoke to XSol and has been produced/included because engineer feedback proves that the PCB can still be at fault even if the permanent voltage between purple and brown is present (manufacturers test).
There are also other fan tests in XSol not recognised by the manufacturers - these are all based on engineer feedback and rigorous testing of working and faulty components to cover issues experienced in the field and make diagnosis of faults on these appliances easier and more accurate.
The voltage change from standby to demand is very small and only happens once each time the appliance has been powered up and a demand created. This is why it is extremely important to follow the test in XSol carefully as the voltage increase is easily missed.
The fan connector must be removed from the fan so the voltage change is not masked but the harness must be connected to the PCB otherwise the voltage change cannot be seen.
This test is bespoke to XSol and has been produced/included because engineer feedback proves that the PCB can still be at fault even if the permanent voltage between purple and brown is present (manufacturers test).
There are also other fan tests in XSol not recognised by the manufacturers - these are all based on engineer feedback and rigorous testing of working and faulty components to cover issues experienced in the field and make diagnosis of faults on these appliances easier and more accurate.
