Mars Air Systems L-2254 manual Fault No heat, Fault Unit switches to heat while in cool mode

Fault: Fan runs continuously although it is set to cycle with compressor.

Possible Reason/Correction

1.Failed triac on Passport I/O circuit board.

Send for repair or call local service technician (see back of book for a listing).

Fault: No cooling or heating.

Possible Reason/Correction

1.Digital control programmed for heat or cool only.

Elite Control: Press and release the Mode button (bottom right corner of display) until the desired mode LED is lit.

Passport I/O Control: Reprogram parameter P-1.

2."HPF" or "LPF" is displayed. See below.

Fault: No heat.

Possible Reason/Correction

1.Digital Control may be set to Electric Heat, not Reverse Cycle.

Elite Control: Reprogram parameter P-13

Passport I/O Control: Reprogram parameter P-15

Fault: Unit switches to heat while in cool mode.

Possible Reason/Correction

1.De-icing feature enabled due to coil icing up. Elite Control: Reprogram parameter P-7 Passport I/O Control: Reprogram parameter P-8

Fault: Fan coil is iced.

Possible Reason/Correction

1.Improper airflow.

See the General Troubleshooting section above first, before reprogramming digital control.

Reprogram parameter P-7 for Elite or P-8 for Passport I/O. If de-icing cycle does not melt ice, switch a/c to heat until ice melts or use hair dryer to melt ice.

If problem persists, reprogram Low Fan Speed Limit for maximum value. Set P-2 to 55 for Elite or set P-3 to 64 for Passport I/O.

Fault: System runs continuously.

Possible Reason/Correction

1.Improper air sensor location.

Verify display head location with criteria found in the control manual. Install alternate air sensor if neces- sary.

Fault: “HPF” is displayed.

Possible Reason/Correction

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

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-2 to 55 for Elite or set P-3 to 64 for Passport I/O. And, set the Reverse Fan Speeds During Heating Mode parameter to "rEF" (P-12 for Elite or P-13 for Passport I/O), or manually set fan speed to high.

Fault: “LPF” is displayed.

Possible Reason/Correction

1.Low-pressure switch is open due to low seawa- ter and/or low return air temperatures.

Try restarting the a/c unit, the optional low pressure switch has a ten minute shutdown time delay that may be in affect.

2.Low pressure switch is open due to loss of refrigerant.

Check a/c unit for refrigerant oil leakage, call service technician.

Fault: “ASF” is displayed.

Possible Reason/Correction

1.Indicates failed face plate air sensor, alternate air sensor or display cable.

Unplug alternate air sensor if installed or plug in alternate air sensor if not installed. Try another display cable.

L-2254 Troubleshooting 13 ❖ English