[donedidit]

Hi Everyone -- Any advice is appreciated!

My 8 year old York furnace has had a rough season. It began with a high-limit switch that went bad and was replaced. Shortly after being replaced (with the same part number) the roll out switch on top of the burners began intermittently tripping, upon reaching the set temperature or prior to, but NEVER on ignition (which seems like an important observation). This leaves the fan continuously running until the switch is manually reset.

A few weeks ago, while continuing to troubleshoot and observe, in hopes of identifying a pattern, I received an error code for the ignitor, which appeared to be cracked upon closer inspection. I replaced the ignitor, and at the same time, put in a new roll-out switch. I also cleaned and verified the flame sensor to be working properly, tried cleaning out the burner box with air and vacuum.

New problems gone, however, I'm back to the roll-out switch (5 flashes) needing to be reset, intermittently. I also noticed that it appears to need multiple resets between 60-70 but above 72 it could run for hours, sometimes without needing a reset (unless, of course, it reaches set temperature (say 80), then it seems like a 50/50 shot of turing off properly (without tripping of roll off switch).

In summary: It has never tripped on ignition, but mainly when turning off, or before and more frequently at lower temperatures.

I crawl down and re-set the switch every time it trips, but there has to be a way to pinpoint the problem so that I can work towards finding a solution.

Any ideas?

Thanks!
New homeowner

[wmproop]

Have you ever watched, in the burner area ,for any possible flame roll-out or flashback?something /somewhere is overheating the rollout switch. It's a possibility of a cracked heat exchanger that can cause this probablem