yes Went out on a service call today
york furnace model P1XD12N06401
BTU/HR INPUT 80,000 BTU/HR OUTPUT 64,000
PROBLEM:
furnace fires up, after two or three minites high limit open.
even gives fault code for high limit four blinks.
checked air flow the homeowner don't have a filter can see next room when i look up in blower compartment.
evap is on the bottom below the heat exchanger
took high limit out of heat ex changer, ohmed it out when it cools it closes, hot opens.
could this be a faulty limit or em i over looking something,
limits go like this look like working normal but faulty?
well monday going to pick one up.