Mars Air Systems L-2254 manual General Troubleshooting

TROUBLESHOOTING

General Troubleshooting

Also see specific digital or mechanical control troubleshooting sections following these general guidelines.

Fault: Will not start.

Possible Reason/Correction

1.A/C circuit breaker is off.

Turn circuit breaker on at ship’s panel.

2.Control is not turned on.

See mechanical control section of this manual for MCP controls, or see the digital control manual for Elite or Passport I/O controls.

3.Wrong wiring at terminal strip.

Check wiring diagram and correct if necessary.

4.Push-on butt connectors became disconnected during installation.

Disconnect power supply and open electric box, check wiring diagram, correct if necessary

5.Input line voltage is insufficient.

Check power source (shore/generator) for proper voltage. Check wiring and terminals for proper sizes and connections. Verify with a volt-meter that the power at the unit is the same as the power source.

Fault: Fan is not running.

Check specific control troubleshooting section

Fault: No cooling or heating.

Possible Reason/Correction

1.Temperature set point is satisfied. Lower or raise set point.

2.Obstructed seawater flow.

Clean seawater strainer. Check for obstructions at speed scoop thru-hull inlet. Check for a good steady flow from the overboard discharge.

3.Seawater pump may be air-locked.

Remove hose from pump discharge to purge air from line.

4.Loss refrigerant gas.

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

5.Seawater temperature too high for cooling or too low for heating.

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

6.Fan coil is iced (in cooling).

Check your specific control troubleshooting section.

7.Fan is not running.

Check your specific control troubleshooting section.

8.Seawater plumbing is air-locked.

Ensure that seawater plumbing is installed per the guidelines in this manual.

9.Digital control is programmed for Cool or Heat only, or mechanical control thermostat is rotated to far towards either Cooler or Warmer setting.

See digital control manual for reprogramming or see mechanical control operation section in this manual.

10.High pressure switch open (in cooling) due to improper seawater flow.

Strainer or intake may be plugged, sea cock may be closed, check seawater hose for kinks or collapses. Verify pump operation. Check pump circuit breaker if applicable

11.High pressure switch open (in heating) due to improper airflow.

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.

12.High-pressure switch is open in heating mode.

System may cycle on high-pressure if seawater temperature is above 55°F.

13.Compressor's thermal overload is open due to either of the above reasons.

Compressor needs to cool down. Turn system off for a while (it may take up to three hours to reset thermal overload).

Fault: No heating.

Possible Reason/Correction

1.Unit is “cool only”, or if reverse cycle, reversing valve may be stuck.

Tap reversing valve lightly with rubber mallet while unit is in heat mode. Call for service if that does not correct the problem.

L-2254 Troubleshooting 11 ❖ English