Fault: Low airflow.

Possible Reason/Correction

1.Airflow is blocked.

Remove any obstructions in return air stream. Clean return air filter and grille. Check for crushed or restricted ducting, ducting must be as straight, smooth and taut as possible.

2.Fan Coil is iced. See below.

Fault: Fan coil is iced.

Possible Reason/Correction

1.Thermostat set point is too low. Raise set point.

2.Improper airflow.

Remove any obstructions in return air stream. Clean return air filter and grille. Check for crushed or restricted ducting, must be as straight, smooth and taut as possible. See the Digital Controls Trouble- shooting section below for reprogramming options.

3.Supply air is short-cycling.

Redirect supply air so that is not blowing into the return air stream. Seal any air leaks on duct.

4.Humidity level too high. Close hatches and doors.

5.When all else fails.

Switch a/c to heat until ice melts or use hair dryer to melt.

Fault: Water coil is iced in the heating mode.

1.Seawater temperature is below 40°F.

Shut down system to prevent damage to condenser. Allow coil to defrost.

Fault: System runs continuously.

Possible Reason/Correction

1.Set point temperature is improperly set: too low for cooling or too high for heating.

Raise or lower set point.

2.Porthole or hatches open. Close all port holes and hatches.

3.Seawater temperature too high for cooling or to low for heating.

Seawater temperature will directly affect the a/c unit's efficiency. This a/c unit can effectively cool your boat in water temperatures up to 90°F and heat (if reverse cycle option is installed) in water as low as 40°F.

4.Improper air sensor location.

Check your specific control troubleshooting section.

Digital Controls Troubleshooting

Fault: Digital display panel is not lit.

Possible Reason/Correction

1.8-pin display cable plugs are not making contact (unplugged, dirty, bent, or broken pins).

With POWER OFF at the circuit breaker, remove connector and inspect. If damaged, replace connec- tor or entire display cable.

Fault: Fan is not running or runs continuously.

Possible Reason/Correction

1.Digital control is programmed for either fan cycling with compressor or continuous fan operation.

Elite Control: Press and hold the fan button for 5 sec- onds to change to "con" so fan will stay on continu- ously or to "cyc" so the fan cycles with the compressor.

Passport I/O Control: Reprogram parameter P-14.

Note: After the compressor cycles off, the fan will continue to run for 2 minutes in cool mode and 4 minutes in heat mode regardless of parameter setting.

Fault: Fan is not running but the compressor is.

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).

L-2254 Troubleshooting

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Mars Air Systems L-2254 manual Digital Controls Troubleshooting