When you press the manual reset button, does it enable the unit to kick on and run again?
do you know where the limit is on the front wall? Rectangle flat plate 3"x4" with 2 wires hooked to it?
Ok thank you......it sounds as though you have a bad heat exchanger. The roll out switch is there for when the flame goes out of the exchanger and washes back. You will really need to have the exchanger tested to see if craked or plugged.
Not relevent info.
The secondary can have certain cells plugged but if water is backed up the pressure switch can not make contact thus leading to a different code.
I am a factory trained Carrier, Bryant, Payne tech for over 20 years....I can tell you with 100% that if the roll out is tripping consistantly it is bad exchanger or plugged...
Water drain issue = pressure switch code.
I know you are hoping and searching for a better suited diagnosis. But the reality is the roll out is there for one reason....a bad or plugged exchanger.
It is not what we want to hear. I can tell you the Carrier/Bryant 90% furnaces had a real issue with exchangers. They bumped them from 20 year to lifetime warranty due to class action court procedures..they supply the exchanger and cover 4 hours labor.
Usually the customer has about $300 additional cost into job.
Since this is one of the more critical events a furnace can face, I recommend a service call to verify the findings.
This is not just inconvenient.....this is dangerous. The roll out is main protection against C.O. poisoning and fire caused by furnace.
This is the most important safety on the entire furnace.
However....I am more than willing to opt out to another expert for another opinion.
Correct, the roll out is either open or closed so ohming is very definitive or check for 24v in and out.