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Table 28 — Heating Service Troubleshooting
Table 29 — EconoMi$er Troubleshooting
LEGEND
PROBLEM CAUSE REMEDY
Burners will not
ignite.
Misaligned spark electrodes. Check flame ignition and sensor electrode positioning.
Adjust as needed.
No gas at main burners. Check gas line for air purge as necessary. After purging
gas line of air, allow gas to dissipate for at least 5 minutes
before attempting to relight unit.
Check gas valve.
Water in gas line. Drain water and install drip leg to trap water.
No power to furnace. Check power supply, fuses, wiring, and circuit breaker.
No 24 v power supply to control circuit. Check transformer. Transformers with internal overcurrent
protection require a cool down period before resetting.
Miswired or loose connections. Check all wiring and wirenut connections.
Burned-out heat anticipator in thermostat. Replace thermostat.
Broken thermostat wires. Run continuity check. Replace wires, if necessary.
Inadequate heating. Dirty air filter. Clean or replace filter as necessary.
Gas input to unit too low. Check gas pressure at manifold. Clock gas meter for input. If too
low, increase manifold pressure, or replace with correct orifices.
Unit undersized for application. Replace with proper unit or add additional unit.
Restricted airflow. Clean filter, replace filter, or remove any restrictions.
Blower speed too low. Use high speed tap, increase fan speed, or install optional
blower, as suitable for individual units.
Limit switch cycles main burners. Check rotation of blower, thermostat heat anticipator settings,
and temperature rise of unit. Adjust as needed.
Too much outdoor air. Adjust minimum position.
Check economizer operation.
Poor flame
characteristics.
Incomplete combustion (lack of Check all screws around flue outlets and burner compartment.
combustion air) results in: Tighten as necessary.
Aldehyde odors, CO, sooting flame, or floating flame. Cracked heat exchanger.
Overfired unit — reduce input, change orifices, or adjust
gas line or manifold pressure.
Check vent for restriction. Clean as necessary.
Check orifice to burner alignment.
Burners will not Unit is locked into Heating mode for a Wait until mandatory one minute time period has
turn off. one minute minimum. elapsed or power to unit.
PROBLEM POTENTIAL CAUSE REMEDY
Damper Does Not
Open
Indoor (Evaporator) Fan is Off Check to ensure that 24 vac is present at Terminal C1 (Common Power)
on the IFC (Indoor [Evaporator] Fan Contactor) or that 24 vac is present at
the IFO (Indoor [Evaporator] Fan On) terminal. Check whether 24 vac is
present at PL6-1 (red wire) and/or PL6-3 (black wire). If 24 vac is not
present, check wiring (see unit label diagram).
Check proper thermostat connection to G on the connection board.
No Power to EconoMi$er Controller Check to ensure that 24 vac is present across Terminals 24 VAC and
24 V COM on the EconoMi$er control. If 24 vac is not present, check wiring
(see unit label diagram). If 24 vac is present, STATUS light should be on
constantly.
No Power to G Terminal If IFM is on, check to ensure 24 vac is present on G Terminal of the
EconoMi$er controller. If 24 vac is not present, check wiring (see unit
label diagram).
Controller Fault If STATUS light is flashing one flash, the EconoMi$er controller is
experiencing a fault condition. Cycle power to the controller. If condition
continues, replace the EconoMi$er controller.
Thermostat Fault If STATUS light is flashing two flashes, the EconoMi$er controller senses
the thermostat is wired incorrectly. Check wiring between the thermostat
and the connection board in the electrical panel. The fault condition is
caused by Y2 being energized before Y1.
Actuator Fault Check the wiring between the EconoMi$er controller and the actuator.
Hold CONFIG button between 3 and 10 seconds to verify the
actuator’s operation. (This process takes 3 minutes to complete.)
EconoMi$er
Operation Limited to
Minimum Position
Minimum Position Set Incorrectly Verify that the MIN POS (%) is set greater than zero. Adjust MIN POS (%)
to 100% to verify operation, and then set to correct setting.
EconoMi$er Changeover Set Point Set Too
High or Too Low
Set at correct value. See Table 4.
Supply Air Temperature Sensor Faulty If STATUS light is flashing 4 flashes, Supply Air Temperature Sensor is
faulty. Check wiring or replace sensor.
Outdoor Air Temperature Sensor Faulty If STATUS light is flashing 5 flashes, Outdoor Air Temperature Sensor is
faulty. Check wiring or replace sensor.
Damper Position
Less than Minimum
Position Set Point
Supply Air Low Limit Strategy Controlling The supply-air temperature is less than 7 C (45 F), causing the minimum
position to be decreased. Refer to the Start-Up instructions. Verify correct
setting of MIN POS (%). If correct, EconoMi$er is operating correctly.
Damper Does Not
Return to Minimum
Position
CO
2
Ventilation Strategy Controlling If a CO
2
sensor is being used, and the damper position is greater than
minimum position, the ventilation control strategy is controlling. Refer to
the Start-Up instructions. EconoMi$er is operating correctly.
Damper Does Not
Close on Power Loss
Damper Travel is Restricted Check to ensure the damper is not blocked.
IFM —
Indoor Fan Motor
PL —
Plug