Troubleshooting - Lennox MS8 SERIES Installation And Service Procedures

Troubleshooting

SYSTEM FAILED START UP (ALL SIZES)
System failed to start.
Breaker trip or
blow fuse.
Non-responsive
system after power
up. No audible
response and
control input is
unresponsive.
No response from
remote control.
MS8C / MS8H (208-230V)
APPLICABLE UNIT SIZE(S): All
APPLICABLE ERROR CODE(S): NONE
Circuit breaker immediately trips when
set to ON on remote control.
Circuit breaker trips after
system has been running for
a few minutes.
No power.
Power connections are incorrect.
Fuse on outdoor control has blown.
Transformer connection is loose, bad
contact, or the transformer has malfunction.
Outdoor control has malfunction.
Remote control batteries are dead
Remote control has malfunction.
Indoor unit infra-red receiver wire harness
has a loose connection.
Infra-red receiver has malfunction.
System voltage is low
FIGURE 83
Page 72
Measure insulation resistance to
ground and see if there is any leakage.
Issue could be system circuit fault. Verify circuit
breaker is installed correctly. If installation is
correct, then replace circuit breaker.
Check power supply circuit.
Check power connections and
repair.
Replace fuse.
Repair wiring connection to the
transformer; measure the output
voltage of the transformer. If incorrect,
replace transformer.
Replace remote control.
Replace batteries.
Press the AUTO (MANUAL) button to
place the unit into AUTO mode. If system
is unresponsive, check wiring between
indoor and outdoor unit. If system is
responsive and runs normally. Verify IR
receiver connection to indoor control is
good and that remote control is working.
Check voltage and if lower than 10% of the rated
input voltage, then determine fault and repair.