Imagine such situation: you purchased Coleman furnaces and faced the problem with their functioning. You should get the point that it’s absolutely normal and if the problem seems to be rather serious, it doesn’t mean it’s really this way. Just look for the necessary model in the manual here and start the repair which isn’t going to take long time.
It sounds simple, but even the best of us have days that we are not thinking clearly. In dual systems, make sure the thermostat is set on Heat, not Cool. Most programmable thermostats run on batteries; make sure they have plenty of charge left. Also, verify that the unit has power; it should be plugged in with the emergency switch in the ON position
Change the air filter
One of the top causes of a furnace blowing cold air is reduced air flow from a clogged filter. To prevent this problem, change the filter at least once a month while the system is in operation. Replace dirty filters more frequently if necessary. Foam filters can be washed and reused if they do not show signs of damage and are dried thoroughly. Box filters must be replaced each time. They should also be installed with the arrow printed on the frame facing the furnace
Relight the pilot light
Most older gas furnaces have a standing pilot light. If it goes out, the burner will not ignite. Follow these steps to reignite your pilot light
Verify that the gas is on
Turn the gas valve knob to the pilot setting
Press and hold (or depending on your furnace, slide and hold) the knob and use an extended match or grill lighter to ignite the pilot light.
Hold the knob in place for at least 30 seconds after the pilot is lit.
Slowly release the knob and turn it to the on position.
If the pilot light goes out immediately, wait five minutes for the gas to dissipate and repeat Steps 2-5. If there is air in the line, it may take several tries to purge it before the pilot light will stay lit
Check the thermocouple
The thermocouple is a flame sensor that determines whether the pilot is lit. When it senses the pilot light, it triggers the gas valve to switch on, lighting the burner. Check its position; misalignment means the sensor will not work correctly and the gas valve will remain closed. If the thermocouple is correctly aligned but the gas valve is not working, you may need to replace it. The inexpensive part is readily available at retail stores that carry home improvement supplies
Furnace is noisy
Creaks, squeaks and groans
These sounds may be caused by the blower motor assembly. If the belt is cracked or worn, replace it. The belt must also be properly tensioned and positioned. It should have no more than half an inch of slack on either side. Any twisting indicates that an adjustment to the belt pulley is necessary.
Make sure the blower motor is clear of dirt and debris. Fan motors with oil ports should be oiled twice a year. Look for two oil ports on the opposite end as the motor shaft, directly across from each other. Use 1-4 drops of 3-in-1 SAE 20 motor oil in each part
This sound is heard when an electronic spark fails to ignite a pilot light.
Furnace cycles too often
A short furnace cycle may indicate an air flow issue or the thermostat heat anticipator may need to be adjusted. First, check the air filter and replace it if needed. If that does not fix the problem, remove the thermostat cover. Frequent cycling can be caused by a heat anticipator set at .2 or below. Check the manufacturer’s instructions for your furnace model and adjust the anticipator accordingly
Blower motor not working
If the blower motor will not switch on, check the burners first. The fan motor will not engage if the burners are not lit. Next, check the blower motor. Move the fan switch on the thermostat to the position labeled “manual” or “on.” If the motor runs with the fan switch manually engaged, the issue may be a faulty limit switch. If it does not start, check for blown fuses or loose connections in the furnace. Finally, replacing a damaged blower motor or burnt wiring is a job for a professional
Coleman PXXU V Furnace Troubleshooting
NO AIRFLOW OR MOTOR DOESN’T RUN
Verify that the blower wheel is properly tightened on the motor shaft.
Verify 115 Volts AC at the power connector at the motor.
Be sure the connectors at the motor, ignition control and CFM Selection Board are properly connected and fully seated.
Switch the thermostat to CONTINUOUS FAN mode. If the motor does not run, verify 24 VAC on the R to C lines. If there is no voltage correct the cable/wiring, trans- former fault. If there is voltage at the connector, the motor has failed.
Check High Heat, Low Heat or Cool output terminals for 24 volts.
Check motor for tight shaft.
Perform Moisture Check. Be sure motor connectors are facing down. Arrange the wire harness to create a drip loop under the motor. Check for plugged condensate drain. Check for low airflow. Check and plug leaks in return ducts
MOTOR ROCKS BUT WONT START
Check for loose or compliant motor mount.
Perform motor/control replacement check.
MOTOR OPERATION IS INTERMITTENT
Verify that all connectors are firmly seated. Gently pull the motor connector wires at both ends of the cables individually to be sure they are properly crimped into the housings.
MOTOR RUNS WHEN IS SUPPOSED TO BE OFF
Allow a few minutes for the motor to shut off. Motor-off delays are controlled by the ignition control
MOTOR STARTS BUT: RUNS ERRATICALLY
Check the line voltage for variation.
Check low voltage connections at motor, unseated pins in motor harness connectors.
Check “Bk" for erratic CFM command
MOTOR HUNTS OR “PUFFS”
Excessive restriction in duct system or filter. Reduce maximum air flow
STAYS AT LOW CFM DESPITE SYSTEM CALL FOR COOL OR HEAT CFM
Check low voltage wires and connections.
Verify fan is not in delay mode - wait until delay is com- plete.
“R" missing /not connected at motor or terminal strip.
Perform motor/control replacement check.
STAYS AT HIGH CFM
“R" missing/not connected at motor or terminal strip.
Is fan in delay mode? Wait until delay is complete.
Perform motor/control replacement check
BLOWER WONT SHUT OFF
Current leakage from controls into G, Y, or W? Check for Triac switched thermostat or solid state relay.
Determine if it’s air noise, cabinet, duct, or motor noise.