Carrier 48EZ(N) - A Installation Instructions Manual

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Contents

36Table 12 – Troubleshooting Guide–HeatingSYMPTOM CAUSE REMEDYBurners will not igniteWater in gas line Drain. Install drip leg.No power to furnace Check power supply fuses, wiring or circuit breaker.No 24--v power supply to control circuitCheck transformer.NOTE: Some transformers have internal over--current protectionthat requires a cool--down period to reset.Mis--wired or loose connections Check all wiring and wire nut connectionsMisaligned spark electrodes Check flame ignition and sense electrode positioning.Adjust as necessary.No gas at main burners1. Check gas line for air. Purge as necessary. NOTE: After purginggas line of air, wait at least 5 minutes for any gas to dissipate be-fore attempting to light unit.2. Check gas valve.Inadequate heatingDirty air filter Clean or replace filter as necessaryGas input to furnace too low Check gas pressure at manifold match with that on unit nameplateUnit undersized for application Replace with proper unit or add additional unitRestricted airflow Clean or replace filter. Remove any restriction.Limit switch cycles main burners Check rotation of blower, temperature rise of unit. Adjust as neces-sary.Poor flame characteristics Incomplete combustion results in: Aldehyde odors,carbon monoxide, sooting flame, floating flame1. Tighten all screws around burner compartment2. Cracked heat exchanger. Replace.3. Unit over--fired. Reduce input (change orifices or adjust gas lineor manifold pressure).4. Check burner alignment.5. Inspect heat exchanger for blockage. Clean as necessary.Table 13 – Troubleshooting Guide–LED Error CodesSYMPTOM CAUSE REMEDYNo Power or Hardware fail-ure(LED OFF)Loss of power to control module (IGC)*.Check 5--amp fuse son IGC*, power to unit, 24--v circuit breaker,and transformer. Units without a 24--v circuit breaker have aninternal overload in the 24--v transformer. If the overload trips,allow 10 minutes for automatic reset.Limit switch faults(LED 2 flashes) High temperature limit switch is open.Check the operation of the indoor (evaporator) fan motor. Ensurethat the supply--air temperature rise is in accordance with therange on the unit nameplate. Clean or replace filters.Flame sense fault(LED 3 flashes) The IGC* sensed flame that should not be present. Reset unit. If problem persists, replace control board.4 consecutive limit switchfaults(LED 4 flashes)Inadequate airflow to unit.Check the operation of the indoor (evaporator) fan motor and thatsupply--air temperature rise agrees with range on unit nameplateinformation.Ignition lockout(LED 5 flashes) Unit unsuccessfully attempted ignition for 15 minutes.Check ignitor and flame sensor electrode spacing, gaps, etc.Ensure that fame sense and ignition wires are properly terminated.Verify that unit is obtaining proper amount of gas.Pressure Switch Fault(LED 6 flashes) Open pressure switch.Verify wiring connections to pressure switch and inducer motor.Verify pressure switch hose is tightly connected to both inducerhousing and pressure switch. Verify inducer wheel is properlyattached to inducer motor shaft. Verify inducer motor shaft is turn-ing.Rollout switch fault(LED 7 flashes) Rollout switch has opened.Rollout switch will automatically reset, but IGC* will continue tolockout unit. Check gas valve operation. Ensure that induced--draftblower wheel is properly secured to motor shaft. Inspect heatexchanger. Reset unit at unit disconnect.Internal control fault(LED 8 flashes)Microprocessor has sensed an error in the softwareor hardware.If error code is not cleared by resetting unit power, replace theIGC*.Temporary 1 hr auto reset(LED 9 flashes) Electrical interference impeding IGC software Reset 24--v. to control board or turn thermostat off, then on again.Fault will automatically reset itself in one (1) hour.*WARNING : If the IGC must be replaced, be sure to ground yourself to dissipate any electrical charge that my be present before handling new controlboard. The IGC is sensitive to static electricity and my be damaged if the necessary precautions are not taken.IMPORTANT: Refer to Table 11 ---Troubleshooting Guide ---Heating for additional troubleshooting analysis.LEGENDIGC—Integrated Gas Unit ControllerLED—Light---Emitting Diode48EZ -- A

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