Trane Start to Finish R-410A Installation Manual page 33

module must match module input voltage as printed
on module nameplate.
2. Check wire connection tightness.
3. Try to reset the module (interrupt power for
five seconds).
4. If, after reset, module M1-M2 closes, determine which
fault caused module to trip.
5. If M1-M2 remains open, proceed as follows:
Disconnect PTC thermistors from S1and S2 terminals,
and measure the resistance of the PTC using a device
with a maximum output of 3 volts.
• Resistance = ∞.
Open PTC open; replace compressor.
• Resistance = 0 ohms
PTC shorted; replace compressor.
• Resistance >2750 ohm
Wait until the motor has cooled down and
resistance is less than 2750 ohms; reconnect and
try to reset motor protector. Diagnose problem that
caused motor over temperature.
• Resistance = 150 ohms < R< 1250 ohms
Normal resistance value for PTC ambient
temperature.
Test the module within the terminal box
1. Disconnect L-N voltage supply.
2. Disconnect S1-S2 PTC circuit on the module.
3. Disconnect M1-M2 safety circuit control contacts.
4. Apply a resistance between 150 and 1250 ohms across
S1-S2. This simulates a functional, cool motor.
5. Reconnect L-N voltage supply. Ensure that the voltage
to L-N has been disabled for at least 5 seconds. This
will reset the module.
6. Check M1-M2 with ohmmeter.
7. M1-M2 closed—Module okay.
8. M1-M2 open—Module defective.
PART-SVN234B-EN
Troubleshooting
33