Boyertown Furnace RSM 500 Installation, Operation And Maintenance Manual page 33

levels are greater than 100K, the control unit is functioning properly. If the multimeter resistance
levels are less than 100K replace the control unit.
Motor Verification
1. Disconnect or turn off power to the furnace, air handler, or system being serviced and wait 2
minutes. This allows the capacitors in the control unit to fully discharge.
2. Remove control unit if still mounted on motor. See control unit verification steps 2 and 3.
3. Inspect connector on back side of motor for bent, damaged, or recessed wires. Replace motor if
connector contains bent, damaged or recessed wires or terminals.
4. Check phase to phase resistance between each of the three phase terminals in the motor connector.
Resistance levels between any two contacts should be equal. If resistance is equal motor is
functioning properly. Replace motor if the resistance levels are not equal or are open or short
circuited.
5. Inspect the magnets through the back side of the motor for broken or chipped magnets in the rotor
core. Replace motor if magnets are chipped or broken.
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