Pioneer QUANTUM INVERTER Series Service & Troubleshooting Manual page 149

8.5 4-way Valve Check
1. Power on the system, and use a digital tester to measure the voltage. When the unit operates in cooling, it is 0V.
When the unit operates in heating, it is about 230VAC.
If the value of the voltage is not in the range, the PCB has faulted and needs to be replaced.
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2. Turn off the power, and use a digital tester to measure the valve's resistance. The value should be 1.8~2.5 KΩ.
Troubleshooting 41
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