I have been in my house for 5 years when the thermostat calls for heat, the inducer blower comes on and almost immediately I hear the pressure switch click and then the relay on the main board clicks and the inducer blower goes off. This happens over and over for a couple of minutes and finally the inducer motor stays on and then the igniter glows and the furnace heats... The furnace would always eventually heat the house. This is way it always worked until this week.. NOw the inducer blower cycles the same way but it never ignites... I hear gurgling when it is running inside the drain trap assembly. I turn the power off for 10 minutes and turn it back on and it may heat for a day, but then it stops ignititng again. I had the service man out and he replaced the pressure switch. For $80 and this did nothing...
I refuse to call him again, I don't think he understood the furnace at all.
Should there be gurgling in the drain trap?.
Is it a pressure switch or a vacuum switch?
HELP please,
Thanks in advance

The drains are partially plugged I'm guessing. A plugged drain will cause pressure switch issues.

After the furnace has run a while, when the drain can't keep up, it causes the furnace to lock out with a pressure switch fault code.

I have been in my house for 5 years when the thermostat calls for heat, the inducer blower comes on and almost immediately I hear the pressure switch click and then the relay on the main board clicks and the inducer blower goes off. This happens over and over for a couple of minutes and finally the inducer motor stays on and then the igniter glows and the furnace heats ...The furnace would always eventually heat the house. This is way it always worked until this week.. NOw the inducer blower cycles the same way but it never ignites... I hear gurgling when it is running inside the drain trap assembly. I turn the power off for 10 minutes and turn it back on and it may heat for a day, but then it stops ignititng again. I had the service man out and he replaced the pressure switch. for $80 and this did nothing...
I refuse to call him again, I don't think he understood the furnace at all.
Should there be gurgling in the drain trap? ...
Is it a pressure switch or a vacuum switch?
HELP please,
Thanks in advance
I finally bought a new system board and the problem disappeared.
Easy fix.