Emerson 2 - Manual (Page 33)

Troubleshooting
27
8.0 T
ROUBLESHOOTING
Table 14 Troubleshooting guide
Problem Probable Cause Remedy
Unit will not start No power to unit Check voltage to input circuit breaker.
Control voltage circuit
breaker open
Locate short and reset breaker.
Shut off by external
thermostat or stat is
defective
Check operation of thermostat.
No cooling Low refrigerant
charge
Check with gauges.
Compressor contactor
not pulling in
Check voltage at contactor. If not present refer to print and determine
voltage loss. Check enthalpy sensor for full CCW or D setting.
No output from
thermostat
Check operation of stat. Should have voltage output to Y terminal during
cooling.
Unit cycles on
high pressure switch
Loss or restriction of
air flow
Check condenser blower assembly for proper operation. Check for dirty
coil or inlet grille restriction.
Defective fan cycling
control
Switch should make @ 240 PSIG ±10 (1655 kPa ±68.9). (Check settings
on adjustable switch when supplied.)
Heat does not operate No voltage output
from thermostat
Check stat for proper output to W terminal.
Fuseable link blown Check for open and replace.
Bad contactor Check for open and replace.