WiremanWireman · HVAC & refrigeration troubleshooting · 2023 NEC ·
HVAC & refrigeration
Condensers, furnaces, heat pumps, thermostats.
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A/C outdoor unit won’t runSplit it at the contactor: is the 24 V call arriving, and is 240 V getting through?Up to 4 stepsCondenser fan won’t spinBearings, the FAN side of the capacitor, voltage at the motor, then the windings.Up to 5 stepsCompressor won’t start or trips the breakerCapacitor, voltage on start, the C-S-R windings, then windings to ground.Up to 5 stepsThermostat blank or no 24 VFind where the 24 V stops: the unit’s power, the transformer, the board fuse or the wire.Up to 5 stepsFurnace no heat (electrical side)Follow the ignition sequence: W call, limits, inducer and pressure switch, igniter, flame proving, blower.Up to 3 stepsHeat pump stuck in defrost or no heatReversing valve signal and coil, the defrost sensor and board, and aux heat.Up to 4 stepsElectric heat strips not workingBreakers, the W call, amps on each element, then elements, limits and sequencers.Up to 5 stepsMini-split error or won’t startPower at each unit, the communication wiring, and what each kind of error code means.Up to 3 stepsWalk-in cooler or freezer defrost problemsIced coils, drain line heaters, the defrost timer and the termination control.Up to 4 stepsRooftop unit won’t startThree-phase power, control transformer, phase monitor, then the safety chain to the contactor.Up to 5 steps