I have a Criterion II heater. Sometimes it works sometimes it don't. I hear the thermostat "click" on, but no spark, no blower, no nothing. The two green lights are always on except when the thermostat triggers "on", then the OK light flashes on and off 4 times. I do notice under the strip where the thermostat wires go, there are two horizontal white things that get somewhat hot?

I have a Criterion II heater. Sometimes it works sometimes it dont. I hear the thermostat "click" on, but no spark, no blower, no nothing. The two green lights are always on except when the thermostat triggers "on", then the OK light flashes on and off 4 times. I do notice under the strip where the thermostat wires go, there are two horizontal white things that get somewhat hot?

I also just looked at the schematic, it says four lights followed by a 2 second pause, which mine is doing, said it is the pressure switch closed. Where I the pressure switch?

I also just looked at the schematic, it says four lights followed by a 2 second pause, which mine is doing, said it is the pressure switch closed. Where i the pressure switch?

Well again, now it fired up noproblem. Don't understand. When it does work, it works fine. But I did learn a little bit more about this thing reading from this site, thanks.

Found out what it was. To the left of the blower is a small round black plastic thing that has a vacuum tube running to the blower. It has a couple of wires running to it as well. When the thermostat kicks in, but nothing happens, I just tap this thing and it fires right up every time. Is this the pressure switch?

Yes this that is the pressure switch. Blow out the vacum tubes and try it again.