i am currently training with a registered gass engineer, and we were at a job today which has stumped us.
initial complaint- boiler does not fire and fan is cycling in speed, and no ignition. trusted mentor said that he had seen this before and could be pcb. Duly changed.
result- fan starts constant speed makes the pressure switch (as indicated by the neon on the PCB), ignition fired, pilot on and then it started!
the main burner came on for 2 seconds then switched off. but it then keeps doing this constantly until you turn the calling for heat off. While it is doing this you can hear contacts in the PCB making and breaking. Manufacture stated it was probably low inlet pressure causing problems with rectification. Gas board actually came out anyway and changed the regulator on meter! (on customers request) and checked pressures at meter and boiler. (must add this condition has just started and boiler has worked without fault for years)
boiler still doing same cycling on burner.
checked voltages from PCB.
voltage to pilot solonoid - 230v when calling. as expected.
voltage to main solonoid - cycling between no volts and Overload.
i can confirm that my fluke meter is working correctly so am bemused as to why the voltage is varying to such a high figure at the gas valve. (the range of my meter is up to 600V!)
This voltage swing was also noted at the pressure switch when the pressure switch had been made on fan start up.
I am a little bemused as to these readings. is it the gas valve (how i do not konw) or is the PCB we have put in to blame (brand new)
your thoughts please?
initial complaint- boiler does not fire and fan is cycling in speed, and no ignition. trusted mentor said that he had seen this before and could be pcb. Duly changed.
result- fan starts constant speed makes the pressure switch (as indicated by the neon on the PCB), ignition fired, pilot on and then it started!
the main burner came on for 2 seconds then switched off. but it then keeps doing this constantly until you turn the calling for heat off. While it is doing this you can hear contacts in the PCB making and breaking. Manufacture stated it was probably low inlet pressure causing problems with rectification. Gas board actually came out anyway and changed the regulator on meter! (on customers request) and checked pressures at meter and boiler. (must add this condition has just started and boiler has worked without fault for years)
boiler still doing same cycling on burner.
checked voltages from PCB.
voltage to pilot solonoid - 230v when calling. as expected.
voltage to main solonoid - cycling between no volts and Overload.
i can confirm that my fluke meter is working correctly so am bemused as to why the voltage is varying to such a high figure at the gas valve. (the range of my meter is up to 600V!)
This voltage swing was also noted at the pressure switch when the pressure switch had been made on fan start up.
I am a little bemused as to these readings. is it the gas valve (how i do not konw) or is the PCB we have put in to blame (brand new)
your thoughts please?
