TechPlus ComfortAire, Service Supplement Manual

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TechPlus
s e r v i c e s u p p l e m e n t
Electrical System Trouble Shooting
Clutch Not Engaging: Power is supplied to the clutch from the blower switch, to
the electronic thermostat and through the H.P. Binary Switch to the compressor.
The blower switch must be turned on to a selected speed before voltage is
supplied to the electronic thermostat.
Check all connections for proper contact and voltage readings.
Condenser Fans not Operating: R1, R2 and R3 relays are energized by the
blower switch at the dash. Once the relay receives 12V, it will energize through
pin 86 and close the contacts. Power will flow out of pin 87 and send 12V to the
Condenser fan motor. Power will also flow from the electrical box through the
circuit breaker to pin 30 of the relay.
Check all connectors for proper contact; ensure that the ground circuit is
complete. Check for correct voltage.
Note: 2 diodes are supplied in these circuits to protect the electronic
thermostats; these two diodes can be found in the condenser wiring
harness at the 6-way connector wire #’s 19 and 20.
Evaporator Fans not Operating Low Speed: Power is supplied to the R4 relay
when the blower switch is set to the low (first) Position. The R4 relay energizes
and sends voltage through pin 87, to and through the ceramic resistor to the
evaporator motors. Power is also supplied from the electrical box through the
circuit breaker to pin 30 of the relay.
Evaporator Fans not Operating Medium Speed:
Power is supplied to the R3
relay when the blower switch is set to the Medium (second) position. The R3
relay energizes and sends voltage through pin 87, to and through the ceramic
resistor to the evaporator motors. Power is also supplied from the electrical box
through the circuit breaker to pin 30 of the R3 relay.
Evaporator Fans not Operating High Speed: Power is supplied to the R2 and
R1 relay when the blower switch is set to the High (third) position. The R2 and
R1 relay energize and send voltage through pin 87, to and through the ceramic
resistor to each evaporator motor. Power is also supplied from the electrical box
through the circuit breaker to pins 30 of both relays.
Check all connectors for proper contact; ensure that the ground circuit is
complete. Check for correct voltage.
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APPENDIX
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