In the Goodman heat pump there are two wiring sources that have to be connected. These two sources are high voltage and low voltage. High voltage is the voltage the unit needs to run. Low voltage is the voltage that is used to control the unit from a thermostat or other controlling device.

Heat pump in alley
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Step 1

Turn off all power sources to the heat pump and properly lock out electric. Check that there is no power present on wires using a voltage meter or tester before you start.

Step 2

Insert the high voltage wire through the hole on the side of the heat pump unit which is called a electrical knockout. Once wires are through the knockout use a electrical connector to secure them. High voltage wire should be sized from manufacturer's recommendation for heat pump's size and length of wire.

Step 3

Cut wires to 8 inches in length and strip the covering back off each wire a ½ inch. You will have three wires for single phase and four wires for three phase. Single phase will be two power wires and a ground, three phase will be three power wires and a ground.

Step 4

Identify the high voltage wires and the ground wire. Ground wire is commonly colored green or identified with green identification tape wrapped around it, while power wires are commonly colored red or black or identified with colored identification tape.

Step 5

Locate ground lug-on unit. A ground lug is a aluminum terminals that is mounted in the electrical compartment away from other components. Loosen the terminal with a screwdriver by turning the terminal counter clockwise. Once loosened slide the ground wire under the terminal and tighten down by turning the terminal clockwise.

Step 6

Locate the contactor in the high-voltage compartment. The contactor is one of the largest components in the compartment and will have labeled terminals L1,L2,T1 and T2 on it; locate terminals L1, L2. L3 if the unit is a three phase one. Loosen terminal L1 by turning the terminal screw counter clockwise; once the terminal is loose slide one of the power wires under the L1 terminal and tighten by turning clockwise.

Step 7

Repeat the terminal L1 process for terminals L2 and L3.

Step 8

Insert low voltage wire through the side knockout that is provided for low voltage wiring using the proper connector. The wire will need to be 18-7. This means 18 gauge with seven conductors. The seven conductors will have different colors for identification purposes.

Step 9

Strip back the jacket off the wire to expose 10 inches of the seven conductors ensuring that you don't nip the conductors. Strip each conductor's jacket ½ inch back exposing the copper wire.

Step 10

Identify wires and terminals. Wire colors are used to identify wires. Terminals are identified by letter or numbers. The most important thing is that the same color wire is connected to the same letter or number on the control board and the thermostat. for example, a blue wire could go on a Y terminal on the heat pump control board as long as the blue wire is attached on the other end to the Y terminal on thermostat or other controlling device.

Step 11

Locate the heat pump low-voltage terminal board. It will be a set of seven terminals with the letters R,G,O,W1,W2,Y and C.

Step 12

Loosen terminal R by turning the terminal counter clockwise, taking the red wire and wrapping the exposed copper around the terminal clockwise. Tighten the terminal clockwise to secure. The other end of conductor should be terminated at R terminal of the thermostat or other control device. Loosen terminal G by turning counter clockwise; using the green conductor wrap exposed copper around G terminal clockwise. Tighten terminal clockwise to secure. The other end of conductor should be terminated at G terminal of the thermostat or other control device. Loosen terminal O by turning counter clockwise; using the orange conductor wrap exposed copper around O terminal clockwise. Tighten terminal clockwise to secure. The other end of conductor should be terminated at O terminal of the thermostat or other control device. Loosen terminal W1 by turning counter clockwise; using the white conductor wrap exposed copper around W1 terminal clockwise. Tighten terminal clockwise to secure. The other end of conductor should be terminated at W1 terminal of the thermostat or other control device. Loosen terminal W2 by turning counter clockwise; using the brown conductor wrap exposed copper around W2 terminal clockwise. Tighten terminal clockwise to secure. The other end of conductor should be terminated at W2 terminal of thermostat or other control device. Loosen terminal Y by turning counter clockwise; using the yellow conductor wrap exposed copper around Y terminal clockwise. Tighten terminal clockwise to secure. The other end of wire should be terminated at Y terminal of the thermostat or other control device. Loosen terminal C by turning counter clockwise; using the blue wire wrap exposed copper around C terminal clockwise. Tighten terminal clockwise to secure. The other end of conductor should be terminated at C terminal of the thermostat or other control device.

Step 13

Ensure no conductors are touching other terminals or wires on both terminal board and thermostat. Power can now be turned back on and heat pump can be tested.