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16.0 TROUBLE SHOOTING
In diagnosing common faults in the heat pump system, develop a logical thought
pattern as used by experienced technicians. The charts which follow are not intend-
ed to be an answer to all problems but only to guide the technician’s thinking.
Through a series of yes and no answers, follow the logical path to a likely conclu-
sion.
A novice technician should use these charts like a road map. Remember that the
chart should clarify a logical path to the problem’s solution.
16.1 ELECTRICAL CHECKS FLOW CHART
Unit Running?
NO
YES
Thermostat Problem?
Go to
Mechanical Checks
YES
NO
for Cooling or Heating
Repair and Recheck
Transformer Problem?
YES
NO
Repair and Recheck
Voltage on Compressor
Side of Contactor?
YES
NO
Run Capacitor
Voltage on Line
Side of Contactor?
Start Capacitor
NO
YES
Potential Relay
Circuit Breakers
Compressor Contactor
Compressor Internal
or Fuses Open
Overload Open
Hi Pressure Cut-Out
YES
Compressor Winding Open
Hot Gas Sensor
Compressor Winding
Unit Wiring and
Grounded
Compressor Time-Delay
Connections
Outdoor Fan Motor
Unit Wiring and
Grounded
Connections
Grounded Capacitor
Replace Fuses
or Reset Breakers
and Recheck System
