Mars Air Systems L-2254 - Manual (Page 11)

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English L-2254 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.