Operation; Functions; Compressor Speed Control; Diagnostic Led - Coastal Climate Control Guardian Manual

Operation: The Coastal
1. Controls and displays refrigerator or freezer box temperature and compressor operational status.
2. Provides for automatic or manual compressor speed control for maximum possible system efficiency.
3. Gives audible and visual indication of temperature anomalies and system malfunction.
1. The Coastal MK II Digital Thermostat/Thermometer is pre‐installed and set to work as a refrigerator control
with a set point of 40 degrees Fahrenheit. Refer to separate instruction sheet for details on how to adjust temperature
set point, differential, temperature scale (F or C), and alarm thresholds.
2. Compressor speed is controlled by adjusting the rotary knob. When in the "AUTO" position and with Merlin
Smart Speed Controller installed, the compressor will automatically run at the most efficient speed, and changing the
knob position during that cycle will have no effect. If a manual speed is set, the compressor will run at that speed on the
next start‐up. Without Merlin SSC installed, the "AUTO" setting is non‐operational and will become the lowest speed
setting. The lowest speed should be set so that: (a) the box maintains the desired temperature, and (b) the compressor
runs for between 30 and 45 minutes in the hour. The principle behind controlling compressor speed being that the
longer and slower a compressor can be run, the more efficient it will be and the less power it will consume overall.
3. The Diagnostic LED, labeled "FAULT", will display a flashing error code of between one and five flashes
dependent on the nature of the fault, as listed below. Each flashing error code cycle is repeated every 4 seconds. When
a fault is detected, the compressor will stop but the fan or water pump, if applicable, will continue to run. A re‐start will
be attempted approximately every 60‐90 seconds. The fan or water pump will stop during restart attempts.

One Flash – Indicates low voltage. Voltage at terminals on the Danfoss controller has dropped to less than 10.4v.
Voltage must then rise above the cut‐in voltage of 11.7v before the compressor will attempt a re‐start. NOTE: If
initial power applied at start‐up is less than 11.8 volts: No code flashing on the diagnostic LED, thermostat digital
display will be lit, but the compressor will not start until the voltage has risen above 11.8 volts.

Two Flashes ‐ Indicates an overload on the Fan output. The fan output cannot support an average load greater
than 0.5 amp, or a peak load greater than 1 amp for two seconds.

Three Flashes – Indicates that the compressor cannot start due to too high a differential pressure in the
compressor. This is a common problem where poor voltage, or breaks in the power supply or thermostat wiring
cause the controller to attempt a compressor re‐start too soon after it has been stopped for some reason.

Four Flashes – Indicates that the compressor cannot reach minimum speed of 1,850 RPM.

Five Flashes – Indicates that the electronics heat sink has exceeded 212 deg F (100 deg C). This can be due to an
overcharge of refrigerant, water in the system, or excessive ambient temperatures combined with a compressor
operating under extreme load. A re‐start will be attempted when heat sink has cooled to 170 deg F (80 deg C).
PO Box 4535 Annapolis MD 21403 USA – www.frigoboat.com – info@frigoboat.com – 301‐352‐5738
Guardian - Operation
Guardian
performs three functions: