Marine Air HVAC systems

Marine Air Conditioners INITIAL START UP
          A) Open Seacock
          B) Prime sea water suction pump
          C) Position thermostat to 'OFF' and set desired temperature
          D) Open all vents and be sure nothing is restricting air now into the return air intake of your unit.
          E) Position thermostat to "A/C" and 'FAN" to "AUTO". After the 4 minute built in thermostat delay your unit should start operating. Immediately check for steady water flow from "water out" fitting on the outside surface of boat. If water flow is erratic or missing, immediately put thermostat in "OFF' position and refer to Trouble Shooting Guide.
            F) Once your unit is running, you may program your digital thermostat to whatever programs you desire using the Thermostat Operating Manual provided.

SHUT DOWN  
            A) Put thermostat in "Off' position and "Fan" in "Auto". Then place circuit breaker to "Off'. NOTE: When leaving your boat unattended for long periods of time it is always a good policy to close all seacocks
. THEORY OF OPERATION 
            A) GENERAL All air conditioners operate the same regardless of the capacity of the unit. The only exception to this rule is when the unit is equipped with electrical heat or reverse cycle heat pump. The digital thermostat is the master control of the system and dictates the operational mode of the air conditioning unit thru an electrical box (see Figure 2). Though the thermostat has many optional modes such as programming time of day, day of week, etc. - all you need to know to operate the basic functions of Cool and Heat is to set the desired temperature using the Up and Down Arrows and to put the "A/C" "Off' - "Heat" Switch in the applicable position. Remember, the thermostat has a built in delay and you should familiarize yourself with its operation with the booklet provided.
           B) ELECTRICAL The thermostat is supplied 24 VAC from the electrical control box which the thermostat uses to activate the appropriate controls in the electrical box. For instance, when the thermostat "A/C" and "Heat" Switch is placed in the "A/C" position, the compressor contactor relay and fan relay are energized providing 115 VAC to the compressor and the fan. If the "A/C" and "Heat" Switch is in the "Off' position and the Fan switch is placed in the "Fan" position, the fan relay only will be activated providing 115 VAC to the fan which will run circulating ambient cabin air. There will be no cooling of the air unless the "A/C" and "Heat" Switch is in the "A/C" position. In the "Fan" position the fan will run continuously as long as the switch remains in the "Fan" position. Marine air-conditioners come in two types of heating units. The first is electric heat where heater coils are activated and the fan pulls returned air across the coils and discharges in the cabin area. The second method of heat is provided by reversing the flow of Freon through the unit, creating a "heat pump" similar to those in homes. When the "A/C" and "Heat" Switch is in the "Heat" position the heat contactor will be energized in lieu of the Compressor Contactor on electric heat units. The compressor does not run in the "Heat" position on electric heat units. On reversing valve units (heat pumps) the reversing valve relay will activate along with the compressor contactor relay reversing the flow of Freon, causing the evaporator to be the unit heat exchanger. The unit will operate exactly the same as in "A/C" but heat will be produced.
           C) WATER FLOW Water enters the boat through the Foot Scoop under the boat, up through the seacock, then through the strainer into the 3/4" pump input. The pump forces the water through the condenser coils cooling the Freon and is then ejected overboard through the thru hull discharge port

. TROUBLE SHOOTING GUIDE THERMOSTAT IN A/C POSITION - NO OPERATION.
        After you are confident that the thermostat time delay has been completed and the unit is not operating, perform the following checks:      
       A) Check the thermostat battery and make sure that the thermostat is properly programmed. Unit will not turn on unless the "demanded" temperature setting is lower than the cabin temperature. NOTE: On some model air conditioners, If cabin temperature is over 99 degrees and thermostat is displaying "HI", the ambient air around the thermostat must be reduce to a temperature less than 99 degrees. This is normally accomplished by merely airing out the cabin by opening your hatches.
          B) Check power source to boat
         C) Check unit circuit breaker or breaker box for power in and out.
          D) Check 115 VAC leads on unit electrical box for tightness, condition and proper polarity.
          E) Check for 24 VAC at the thermostat connector block located on the side of the air conditioner's electrical box. If 24 volts is present and all of the above checks are positive, the thermostat is faulty. If 24 volts are not present, the problem is in the electrical box. This could be a faulty transformer or a lead may have vibrated loose. At this point you should call the manufacturer. WARNING: Never open the electrical box unless the 115 volt circuit breaker has been placed in the 'OFF" position and you have checked to make sure no 115 volt power is present. Dangerous electrical shock could be experienced if power is left on and box is opened.

THERMOSTAT IN "A/C" - FAN RUNS - COMPRESSOR DOES NOT
         A) Put thermostat in "OFF" position. Check compressor safety switch on top of unit. Reset by pushing in button on side of switch. This switch is generally activated by a lack of cooling water. Check pump and all water lines to find the problem. Repair or adjust, then put thermostat back in A/C and check for water flow out of discharge through side of boat. On, Reverse Cycle units the compressor safety switch will also be activated in the heat mode when there is a restriction in air flow such as a closed discharge vent or a dirty filter.
         B) If water is good and pressure switch has not activated. Connect a jumper wire between the wires marked "R" and "B" on the thermostat connector block on the side of the unit electrical box. If compressor runs, thermostat battery is bad or thermostat is faulty. If compressor does not run when jumper is applied, the problem is in the electrical box or the compressor is faulty. You must now contact the factory for help. ·
COMPRESSOR RUNS-FAN DOES NOT
             A) Put thermostat in "OFF' position. Apply a jumper between "R" and G" on the thermostat connector block located on the side of the unit electrical box. If fan runs, thermostat battery is bad or thermostat is faulty. If fan does not run, problem is in the electrical box or the fan is faulty.
 NO WATER THROUGH DISCHARGE IN HULL 
          A) Put thermostat in "OFF' position and check pump for prime.
              B) Check for loose or kinked hoses.
              C) Check if seacock is open.
              D) Clean strainer and check for restrictions.
              E) Check that seacock is not clogged.
              F) If new installation, make sure pump is mounted below water line.

 EVAPORATOR FREEZING
              A) Open all air supply vents.
              B) Check blower operation. 
              C) Return ail blocked - check for dirty filter. 
              D) Insufficient number or size of supply air vents.
              E) Thermostat set too low, not allowing unit to cycle.
              F) Low on Freon, call for help.

CONDENSER FAN OVERFLOWS 
         A) Drain clogged.
              B) Drain hose blocked mis-aligned or kinked.
              C) Unit not shimmed properly to allow flow through drain hole.

CIRCUIT BREAKER WILL NOT STAY ON
              A) Put thermostat in "OFF' position check all wiring external to electrical box and unit for lose or burnt wires.
              B) Check circuit breaker for failure.
              C) If there are no obvious problems, call for Help.

NO HEAT - WITH ELECTRIC HEAT UNIT
              A) Burnt out thermal fuse. Remove aluminum cover over evaporator. Cover is removed by removing the two screws on either side of evaporator and the two screws on the top fan bracket. Cover then slides off to reveal heater strip. Replace thermal fuse by removing the retaining screw. Reassemble in reverse order. Fuse is located on bottom of heater strip. WARNING: Put circuit breaker in "Off" position before removing cover. High voltage is exposed and can cause serious injury.
              B) Heater strip is open. Replace with new strip.

NO HEAT - REVERSE CYCLE UNIT
             A) Lightly tap reversing valve with end of screwdriver handle this may free up a sticky valve.
             B) Reversing valve faulty or electrical box