coleman evcon presidential II 7900 series gas furnace

[sehi87]

furnace has been acting up for the last week or so. it will kick on and run fine but when it kicks off after the cycle is the problem. it is cool to the touch while it is running but after it shuts down the furnace cover where the motor & squirrel cage is located is hot to the touch for awhile until it cools back down! can someone please tell me what the problem is? we have already changed the reset limit switch, gas valve, & thermostat! any info will be greatly appreciated

[Robert]

Are you getting good/normal airflow from registers ?

If so, you may have a motor going bad and overheating. That needs to be checked as it is a fire hazard.


Thanks,
Robert

[gordo48111]

I am curious what your end result was. The outer panel on the blower compartment may feel slightly warm to the touch once the furnace has been off for a time, this is normal. Some heat will rise into the blower compartment after shut down (downflow furnaces) but it shouldn't be so hot you can't keep your hand on the blower shroud. Amp out the motor while it is running and compare with running load amps or full load amps listed on the motor housing label. Make sure the access panel is in place when doing this. If the amp draw is above the motor rating, replace the motor. Check air temperature at register when blower shuts down. Increasing the blower off delay time may be necessary. Usually a 95-100 degree register air temperature at blower shutdown is safe and comfortable. 105 degrees is ok but will lead to the access panel feeling warmer.

[Robert]

If it's "hot to the touch", it is a motor issue, not residual heat from furnace chamber IF there is good airflow from registers.


Thanks,
Robert