Reversing Valve Check - Lennox MCB Series Service Manual

5.4. Reversing Valve Check

a. Power on the system and use a digital tester to measure the voltage when the system is operating in cooling mode and
the reading should be 0VAC. When the system is operating in heating mode, the value should be 230VAC. If the voltage
value is not in the specified ranges, the PCB will be the issue and will need to be replace.
Turn off the system power use a digital tester to measure the resistance. The resistance value should be 1.8~2.5 Ω.
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