Air Sensor Failure - Displayed

1. Indicates failed face plate air sensor, alternate air sensor or display cable. Unplug the alternate air sensor if installed or plug in alternate air sensor if not installed. Try another display cable. 

2. Damaged jack/socket in display head or on circuit board. Visually check to see that pins inside socket are not bent or corroded. Repair or replace display or circuit board if needed. 

Filter Reminder - Flashing

Filter needs to be cleaned or replaced. Clean or replace filter, and reset P-21 to "00"

High Refrigerant Pressure - Displayed

1. High pressure switch is open (in cooling) due to improper seawater flow. trainer 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.

2. 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, and set the reverse fan speeds during Heating Mode parameter P-13 to "rEF", or manually set fan speed to high.

Low AC Voltage - Displayed

1. Supply voltage is too low. Verify power to unit with multimeter. 

2. Voltage is improperly calibrated. Verify that P-22 matches voltage reading to unit with multimeter. Adjust P-22 if necessary.

Low Refrigerant Pressure - Displayed

1. 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 shutdown time delay that may be in effect.

2. Low pressure switch is open due to loss of refrigerant. Check air conditioning unit for refrigerant oil leakage, call service technician. 

Low Pump Flow - Displayed

1. Condenser coil is too hot. Verify that unit is getting water flow, and that condenser is not fouled. 

2. Thermistor is damaged. Unplug water sensor if installed. Try another if it is available. 

3. Damaged jack/socket or circuit board. Visually check to see that pins inside socket are not bent or corroded. Repair or replace circuit board if needed.