Dometic MCS15 - Manual (Page 29)

EN
MCS5, MCS15 Troubleshooting
29
“HPF” (High Freon
Pressure) is
displayed. High-pressure switch is open (in
cooling) due to improper sea-
water flow.
Strainer or intake may be
plugged, seacock may be closed. Check seawater hose for kinks or
collapses.
Verify pump operation.
Check pump circuit breaker if
applicable.
High-pressure switch open (in
heating) due to improper airflow. Remove obstructions in return air
stream.
Clean air filter and grille.
Check for crushed or restricted
ducting (ducting must be as
straight, smooth and taut as
possible).
If problem persists,
– reprogram Low Fan Speed
Limit for maximum value: Set
P-3 to “64”
– set the reverse fan speeds dur-
ing Heating Mode parameter
P-13 to “rEF”, or manually set
fan speed to high
“LAC” (Low AC
Voltage) is displayed. Supply voltage is too low. Verify power to unit with multi-
meter.
Voltage is improperly calibrated. Verify that P-22 matches voltage
reading to unit with a multimeter.
“LPF” (Low Freon
Pressure) is
displayed. Low-pressure switch is open due
to low seawater and/or low return
air temperatures. Try restarting the air conditioning
unit, the optional low pressure
switch has a ten minute shut-
down time delay that may be in
affect.
Low pressure switch is open due
to loss of refrigerant. Check air conditioning unit for
refrigerant oil leakage.
Call service technician.
“PLF” (Low Pump
Flow) is displayed. Condenser coil is too hot. Verify that unit is getting water
flow, and that condenser is not
fouled.
Thermistor is damaged. Unplug water sensor if installed.
Try another if it is available.
Damaged jack/socket on circuit
board. Visually check to see that pins
inside socket are not bent or cor-
roded.
Repair or replace circuit board if
needed.
Problem Possible Reason Solution