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D. Clogged Filter Thermostat and High-Pressure Switch
Confirm the air filter is clean and ConFM is energized and fan blade turns freely. Check
that the condenser coil is not clogged or restricted.
Confirm that appliance location meets factory requirements:
• This appliance is not intended for outdoor use. Normal operating ambient
temperature should be within 45°F to 100°F (7°C to 38°C).
• The appliance should not be located next to ovens, grills, or other high heat
producing equipment.
• The appliance should not be located in a corrosive environment.
• The appliance should be a minimum of 4" (11 cm) from side walls.
• A minimum of 10" (25 cm) overhead clearance should be provided for proper
ventilation.
Diagnosis:
Clogged Filter Thermostat:
This is a N/O switch. Closing temperature
is 163°F±5°F (72°C±2.7°C) and opening temperature is 153°F±5°F (67°C±2.7°C).
When the clogged filter thermostat closes, DB displays "CF" alternating with cabinet
temperature.
CB provides 5VDC from CB K6 connector pin #2 (P wire). Confirm CB 5VDC
CB supply by checking for 5VDC at CB K6 connector pin #2 (P wire) and CB K5
connector pin #2 (open). If 5VDC is not present, CB is bad and must be replaced.
Diagnosis:
High-Pressure Switch:
This may be a N/O (normally open) or
N/C (normally closed) HPS. See "VII. Wiring Diagrams" for cut-out and cut-in
configuration (CB automatically adjusts to N/O or N/C HPS). If HPS trips 3 times in
1-hour, E4 alarm occurs on CB. Press "RESET" on CB. See "II.E.3. LED Lights and
Alarm Safeties Chart." Check that the air filter and condenser are clean. Next, check
that the ConFM is operating. See "III.E.1.8. High-Pressure Switch." CB provides
5VDC from CB K6 connector pin #6 (V wire). Confirm 5VDC CB supply by checking
for 5VDC at CB K6 connector pin #6 (V wire) and CB K5 connector pin #2 (open). If
5VDC is not present, CB is bad and must be replaced.
Legend:
CB
–control board;
ConFM
–condenser fan motor;
DB
–display board;
HPS
–high-pressure switch
High-Pressure Alarm
Compressor discharge pressure is outside
normal operating range. High-pressure
switch has been triggered 3 or more times in
1 hour.
If the high-pressure switch trips 5 times in
1 hour, compressor stops and will not restart.
Press "RESET." If high-pressure switch resets
automatically, alarm will stop and "E4" will
clear when high-pressure switch closes. After
5 high-pressure switch trips, the alarm can be
silenced for 1 hour by pressing the "RESET".
For the service tech to reset this alarm, press
"ALARM RESET" on the control board itself.