[fmkaspick]

T-State is calling, vent fan is running, blower fan is running, have gas and valves open.. . But ignitor doesn't glow.. . Checked voltage to it and have less than 12V.. . What next?

[mygirlsdad77]

Check all limits(high limits and rollout switches). Only the vent fan should run when there is first a call for heat. IF both vent fan and blower are running, it leads me to believe you have a limit problem.

[KC13]

Status light blinking?

[fmkaspick]

As a matter of fact, yes, I did have an error code - 3 flashes - Vent Pressure Switch Error. However, I thought I cleared that when I got the vent fan running by helping it start by turning the blades with a screwdriver.. . Though it's still flashing. This furnace hasn't run since last winter.

[zanec]

If this is an XE 90 unit, I've had problems with the pressure switch and the tube coming from the plenum to the switch collecting condensation which will clog it. I'm not an expert but maybe check the hose and the switch, also the little nipple on the pressure switch itself might be clogged. It worked for me.

[fmkaspick]

I haven't check that yet even though I do recall reading re just such a problem in another post. I'll report the results after I check it.

[zanec]

Ok. Another thing that is most likely the problem: if you manually had to help the fan to start, the motor could be bad or the capacitor could be bad. Sometimes the capacitor will visibly show signs of it being bad like fluid coming out of it or it could be shaped like a soda can that was left in the freezer. The problem code is correct. It's not closing the pressure switch because the fan isn't running in it's sequence time. The fact is, you shouldn't have to help the fan motor start.