Service tech replaced rollout switch, broke the bracket while doing it, and cleaned flame sensor. Charged $300, told me to replace thermostat, and problem still persists. They want another $100 for "call out."
Here is what happened today when I observed its' operation; ( I cleaned the flame sensor, as many on this site suggested)
Blower shuts off. After 30 secs, Igniter comes on, gas valve clicks, burners light up. 15 secs later blower comes on. Furnace runs for 14 minutes. Burners and blower stop, inducer keeps running.
1 min later, igniter comes on, gas valve clicks but no re-light.
2 min later,(repeats) igniter on, gas valve clicks, no fire. Blower runs, cold. LED flashes #1, lockout.
Cycle power off, repower in 30 secs.Furnace goes through re-light cycle, 1 min later blower starts and furnace runs normally; for only 8 minutes. Fire goes out, blower and inducer remain running.
1 min later, igniter comes on, gas valve clicks, but no burners light.. 30 secs later blower shuts off.
1 min later, igniter on, gas valve clicks, no fire.
2 minutes later, igniter on, gas valve clicks, burners light, 30 secs later blower runs.
Furnace runs for 4 minutes, then shuts off, 3 degrees below set point temp.
5 minutes later, blower and inducer start, led flashes code 1 lockout.
Cycle power and furnace relights as it should and contiinues running for over 30 minutes, shutting off at the set point temp. blower and inducer run on for a minute, then shut off too.
I could sure use some help with this, I have had three different techs, from two local York dealers, charge me a bundle of dough but they cannot diagnose it either. I have some diagnostic skills, mostly with big diesel engines, transmissions.
Thank you

If I were you, I would protest the charges you have already paid since you have not received satisfactory results.

If I were you, I would protest the charges you have already paid since you have not received satisfactory results.

This is the fourth "factory trained, dealer tech' I have had work on this darned thing. Same result every time. Runs OK for a week or so, then back to square one. How York qualifies its dealers is a mystery to me.

I cleaned out the inducer housing. Checked the vacuum, ewith a manometer. It holds about 1.5 in H2O constant. The pressure switch activates and completes the circuit.

When it is operating I have 24V at the limit switch, so it is closed, as it should be. It maintains 24V at the yellow lead to the gas valve.
Also have 24V at the rollout switch.

The flame sensor has 1.3 M ohms resistance, and provides 0.000,007 Amps vs a specification of 0.001 Amp. If I disconnect the sensor, the unit runs through the pre start sequence, fires up, then shuts off after 5 seconds; which seems about right. So it seems like it is reading the flame presence, but maybe loww on ampereage?

This morning it was blowing cold again. I cycled the power and it lit up after the second attempt.