CRUISAIR


INSTALLATION, OPERATION, AND MAINTENANCE OF CRUISAIR MARINE AIR CONDITIONING EQUIPMENT

INTRODUCTION

The CRUISAIR remote condensing unit system consists of five basic elements and in some cases several accessory parts. They are:

(1) Cooling Unit
(2) Controls or. switch assembly
(3) Condensing Unit
(4) Installation Kit and
(5) Seawater Pump.

This instruction will describe and explain the function of the basic parts of a CRUISAIR system and will outline the installation, interconnection and startup of a complete system. It also includes maintenance and operation of CRUISAIR equipment in general. CRUISAIR marine air conditioning equipment is designed specifically for use on boats operating in a salt water environment. Units are available in 5000, 7000, 10,000, 12,000. and 16,000 Btu/Hr. capacities operating on 115 volt, 60 cycle AC power-. Additional units for 220 volt, 50 cycle, or 240 volt, 60 cycle power are available in capacities up to 5 tons.

All CRUISAIR equipment is available for cooling only or in the reverse cycle heat pump configuration for heating as well as cooling. CRUISAIR cooling units are available in five configurations to suit different installation requirements and all CRUISAIR components are designed to be compatible with each other allowing many hundreds of individual marine air conditioning systems to be put together to suit varied specific requirements.

Special Note: The Freon (Refrigerant 22) needed to recharge this system requires a licensed installer. Contact any refrigeration company to have this done.

GENERAL DESCRIPTION OF BASIC COMPONENTS

A. Cooling Unit:
The cooling unit is the refrigerant-to-air heat exchanger which is located in the space to be cooled or heated such as a stateroom or salon. The cooling unit is sometimes referred to in the held as the "evaporator" or the "cooling coil" but in this manual we will use the term "cooling unit." The cooling unit is constructed of a series of copper tubes held in place by vertical aluminum fins. Inside these tubes, the system refrigerant gas expands to produce a chilling effect or condenses to produce a heating effect. This chilled or heated tube-fin assembly cools or heats the air forced through it by the fan or blower, which is an integral part of the cooling unit. The cooling unit will always include a capillary tube type refrigerant expansion device and may or may not include a decorator cabinet with controls.

B. Controls or Switch Assembly:
The switch assembly consists of a main switch, a fan speed control and a thermostat. All switch assembly wiring terminates at a color coded terminal strip which is the   electrical center of the CRUISAIR system. From this terminal strip, the 115 volt power is distributed in the proper sequence to operate the cooling unit fan or blower as well as the power to operate the compressor, reversing valve and pump.

C. Condensing Unit:
The condensing unit consists of the refrigerant compressor, the refrigerant receiver, accumulator, refrigerant-to water condenser, the associated electrical components and the system service valves. Power to the condensing unit is fed from the main switch assembly terminal strip through a three or four conductor wire harness. Wiring connections to the condensing unit are made through a polarized plug.

D. Installation Kit:

The installation kit includes:
(1) The refrigerant grade soft copper tubing, 1/4", 3/8" or 1/2" OD sizes used to connect the cooling unit to the condensing unit.
(2) The polyfoam insulation used to insulate the copper tubing to prevent condensation and drippage.
(3) The four conductor wire harness (three conductor for cooling only) used to transmit power from the main switch assembly terminal strip to the condensing unit.
(4) A can of refrigerant gas to be used to purge the installed system before putting it in operation. Installation kits are available in any length up to 50 feet.

E. Seawater Pump:
The CRUISAIR seawater pump serves to circulate raw seawater through the refrigerant-to-water heat exchanger, generally referred to as the condenser. This circulating water condenses the hot gaseous refrigerant into a cool liquid state for transfer through the connecting copper tubing to the expansion device at the cooling unit. So that it will stand the numerous corrosive effects of the raw seawater, the entire water circuit of all CRUISAIR equipment is made of an 80% - 20% alloy of copper and nickel referred to as 80-20 Cupronickel.

CRUISAIR seawater pumps are available in the centrifugal or the rubber impeller, positive displacement types. The centrifugal pumps, which are not self priming, must be installed below the water line and must be plumbed so there are no loops or vertical bends in the plumbing hoses. The pump will then remain primed and not tend to become airlocked. The disadvantages of these installation considerations are offset by the long life and quiet operation of the centrifugal type pumps. If the above plumbing considerations cannot be met, the rubber impeller, positive displacement type pump, which can be installed in any manner, can be used.

INSTALLATION OF BASIC COMPONENTS

A. Cooling Unit:
In all installations, the cooling unit must be installed so that the air outlet is at least three feet from the floor level. Ideally, the cooling unit outlet should be installed as high as possible. The cooling unit must be installed with the condensate drip pan positioned at the bottom of the unit so that the water dripping from the evaporator coil collects in the drip pan. The cooling unit drain must be installed so that the drain tube makes an immediate 1" drop after leaving the drain fitting and must be routed from that point to continue downhill to a suitable drain location. It is recommended that the condensate be drained overboard since it is fresh distilled water that can cause dry rot if allowed to drip on otherwise dry wood. The quantity of water involved on a hot humid day may be as much as several pints per hour.

The cooling unit must be installed so there is an adequate path for the air to circulate freely into the unit from the space being cooled and then from the unit back into the space being cooled. It is important that the cross sectional area of all discharge air ducts and grills be at least equal to the area of the discharge air portion of the cooling unit involved. An exception is the Type C cooling unit (models EB05 and 6 and EBS10, 12, and 16). In these units, the cross sectional area of the discharge air duct must be at least twice the area of the discharge air portion of the units.

The "cross sectional" area refers to the "open" area of a discharge air grill rather than the total area as determined by the overall measurement of the grill itself. For instance, if a grill is made of expanded metal, perhaps only 50% of the area is open for the passage of air. The metal web itself will block air from passing through the other 50%. In such cases, the total area of the grill must be doubled to achieve the required "open" area.

In the return air duct, mount a piece of ordinary household screen wire as close to the cooling unit as possible to serve as an air filter. On a boat there is not so much concern about dirt as there is about lint. Ordinary window screen does an excellent job of catching lint without causing an inlet airflow pressure drop as thicker or more dense filter materials will do. Screen wire is the only recommended air filter material.

For all discharge air applications, wood or plastic frame grills are recommended. Aluminum frame grills will become cold and produce secondary condensation that will drip from the grill frame. If aluminum frame grills must be used, however, a heater strip can be installed behind the lower edge of the frame to prevent condensation. For heater strip electrical connections see CRUISAIR Specifications for SA1 or SA3 Series Switch Assemblies.

B. Controls or Switch Assembly:

In the type A cooling unit, the switch assembly is an integral part of the unit. On all other types of cooling units, the switch assembly is supplied as a separate item. When using the type A cooling unit, never remove the switch assembly from the cabinet and install it in a remote location . The fan speed control rheostat will produce an excessive amount of heat if it is installed away from its well ventilated normal position in the side of the mahogany cabinet.

The switch assembly for all types of cooling units except type A has a three position type fan speed control which produces no heat at the switch assembly. The main switch assembly has three knobs and the plate is printed either for horizontal or vertical installation. (specify preference when ordering).
The switch assembly is designed to be mounted over the opening you cut to receive it and is fastened from the front with four screws. The wiring from the three control switches terminates in a color coded terminal strip that should be securely mounted in a suitable place with two screws. This terminal strip is the center of the system's electrical connections. These connections are typical for a CRUISAIR 115 volt systems. Switch assemblies for cooling only systems are different from those for cooling and heating and cannot be interchanged. Operation of the controls will be covered in section IV-D.

The thermostat in the switch assembly has a 36" capillary tube leading from it to a temperature sensing bulb. This bulb must be located in the system's return air stream so that the bulb is exposed only to the air returning from the space being cooled or heated. If this detail is not considered, the thermostat will have little or no control over the operation of the system. 10' and 20' capillary tube lengths are available.

C. Condensing Unit:
CRUISAIR condensing units are designed to be installed in any location. They are not affected by moisture, vibration or ambient temperatures up to 140oF. No ventilation is required. The units can withstand the normal pounding encountered on a pleasure yacht in a heavy sea. All refrigeration components are hermetically sealed, and all electrical components are spark-proof for maximum safety. Install the condensing unit wherever space permits. Make sure the wood base is positioned at the bottom of the unit on a horizontal plane. Fasten the condensing unit securely.

Cooling for the refrigerant condenser in the condensing unit is provided by the flow of seawater through the unit. The compressor in the condensing unit is cooled by the refrigerant gas returning to the compressor in a cold and un-superheated state. The CRUISAIR condensing unit is sufficiently quiet to allow installation under a bunk or in a locker if engine room space is not available.

D. Installation Kit:
1. Copper Tubing: When installing the two connecting copper tubes between the cooling unit and the condensing unit, there are several important factors to consider. First, the tubing can be run in lengths up to 50 feet. It can run uphill, downhill or sloping as required and can have as many bends as necessary . (avoid sharp bends and do not use soldered elbows). The tubing should be insulated to prevent moisture from forming on the tubes and dripping off.

CAUTION: Always insulate the tubes separately. Never allow the two tubes to physically touch each other. On cooling only systems, only the largest tube needs to be insulated. On heating and cooling units, both connecting tubes must be insulated separately. Be sure to insulate the connecting flare nut joints carefully to prevent dripping of condensed moisture from these joints.

CAUTION: Always use refrigeration grade, seamless, soft copper tubing. Never use neoprene, Teflon, rubber or any other type hose or tube. The refrigerant used in the CRUISAIR system is monochlorodifluoromethane, or refrigerant #22. This gas is not compatible with any tubing except copper (automotive units use neoprene refrigerant lines because a different type of refrigerant is used). The copper tubing is connected to the cooling unit and condensing unit with flare joints. Flares of exceptional quality are essential to prevent refrigerant leaks. Flares must be of the 45" single flare type. DO NOT use a double flare. The flare should be large enough in diameter to fill the flare nut completely. (see Figure 3-1)

cruisair-fig3-1.gif (3225 bytes)

Only the large forged flare nuts, such as are supplied with CRUISAIR equipment, should be used. DO NOT use long stem machined flare nuts. Flare nuts should be tightened until the nut ceases to offer resistance to tightening. This is the point where the flared portion of the copper tubing is beginning to flow or mash under the force of the nut being tightened. In general terms, tighten 1/4" flare nuts with strength of your forearm, 3/8" flare nuts with the strength of your entire arm and 1/2" flare nuts with the weight of your body. After the tubing is insulated and in place, secure it well with copper clamps.

2. Wire Harness: The wire harness which connects the condensing unit to the main switch assembly terminal strip is CRUISAIR part number 31722. It is supplied in any length with a polarized plug on one end. This plug fits into the condensing unit. The other end of the wires in the harness attach to the main switch assembly terminal strip with crimp on terminals. The harness is always supplied with four wires, one white #12, one purple #12, one red #14 and one blue #14. On cooling only systems, the blue wire is not used and can be trimmed off at the ends of the harness. Normally, the wire  harness is run along with the connecting copper tubing but this is not necessary. For wire harness to polarized plug wiring details, see Figure 3-2.

cruisair-fig3-2.gif (4635 bytes)

E. Seawater Pump:

1. Centrifugal vs. Positive Displacement Type and Plumbing:
The CRUISAIR remote condensing unit system has a seawater cooled condenser and a pump is necessary to provide a continuous flow of water thru the condenser. Two basic types of pumps are offered:

  • the centrifugal pump or,

  • the rubber impeller ( positive displacement type)

The centrifugal pump is much quieter and has a much longer life than the rubber impeller pump. The centrifugal pump, however, has one inherent characteristic you must consider before deciding on its use. Without question, the centrifugal pump is strongly recommended whenever the following conditions can be met:

A.)  The pump inlet must be completely below the water line at all times whether the boat is at rest, under way or in a rolling sea. A centrifugal pump produces no suction lift at all. If the inlet is above the water line, the pump will not operate unless it is primed each time it is restarted.

B.)  The water hoses from the seawater thru-hull fitting to the pump, as well as the water hoses from the pump to the condensing unit and the hoses from the condensing unit overboard must all be installed so that they are self draining. In other words, if the boat is lifted straight up out of the sea, the pump and all the associated plumbing must drain completely. This is absolutely necessary. If the plumbing system is not self draining, it will not be self purging (to purge is to expel air). Whenever air gets into the system, such as can easily happen when the boat operates in a heavy sea or makes a sharp turn, this air will be trapped in the pump itself. With air in the pump no pressure can be produced to expel the air. The water flow then stops and the system is airlocked. If this happens, the outlet hose from the pump must be loosened to allow the air to pass out of the pump so that water will flow in behind it. This re-establishes the pressure needed to provide a flow of water. See Figure 3-3, below.

NOTE: In many installations, there are several condensing units on a boat. In all cases, we recommend using only one seawater pump that is large enough to provide water to all of the condensers involved. See the table in Figure 3-4 for details. ( This link opens in a new window.)

NOTE: The plumbing in the system in Figure 3-3 is self draining and self purging because the water flow is constantly uphill to the point marked 7 and then flows constantly downhill from that point overboard. If this boat were lifted straight up, all of the water in the system would drain out at points 1 and 8.

An improperly plumbed system would be created if point 7 were allowed to drop below point 6. Under these conditions, if the boat were lifted straight up, water would remain in the o\overboard hose between points 6 and 8. The system would not be self draining and pump air-locking problems would result.

If the two conditions critical to the successful installation of a centrifugal pump cannot be met, a rubber impeller, positive displacement pump, which has the ability to pump air as well as water, will have to be used.

In a conventional yacht hull, proper plumbing of the centrifugal pump is usually no problem. In shallow draft boats, such as houseboats, however, it is a significant problem. In most houseboat installations, the positive displacement pump is used.

2. Wiring: To wire the pump, insert the black and white pump wires in the lower left and center slots of the wire harness polarized plug. The green pump wire is attached to the condensing unit chassis as a ground. See Figure 3-5 (below) for details.

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cruisair-fig3-3.gif (3914 bytes)

Figure 3-3 description:

1 Scoop type thru-hull fitting located no more than 6" from the keel, ahead of the stuffing box, and aft of the forward engine room bulkhead.

2 Shut-off valve or seacock.

3 Seawater Strainer. Large outside strainer may be used instead of the inside strainer.

4 Seawater pump. Must be below the water line.

5 Condensing unit inlet (lowest of the two fittings).

6 Condensing unit outlet (highest of the two fittings).

7 High point in plumbing system. There can be only one high point in a self-purging plumbing system.

8 Overboard fitting. Install 1" to 2" above the water line so that the discharge water will run quietly, but will be visible from on deck. Use a separate overboard for each condensing unit.

End of Figure 3-3 description

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STARTUP PROCEDURE

A. Final Inspection:
The following is a list of items to be checked before any CRUISAIR system is purged or started. Be sure that the:


1. Cooling unit is bolted securely in place.

2. Cooling unit discharge air cross sectional open area is equal to the face cross sectional open area of the air outlet portion of the evaporator coil as a minimum. In type C cooling units, this area must be twice that of the unit outlet area.

3. Cooling unit return air cross sectional open area is equal to the face area of the unit evaporator coil as a minimum.

4. Return air to the cooling unit is filtered through a screen wire filter.

5. Switch assembly terminal strips are securely mounted in a dry place, safely out of reach.

6. Thermostat temperature sensing bulb is installed in the cooling unit return air stream.

7. Cooling unit condensate drain is in place and working. Test by pouring two quarts of water rapidly into the cooling unit drip pan.

8. Cooling unit wires are connected securely to the switch assembly terminal strip color to color.

9. Flare nut joints at the cooling unit are tight.

10. Flare nut joints at the cooling unit are insulated to prevent dripping. Insulate after testing for leaks.

11. Wire harness to the condensing unit is securely connected to the switch assembly terminal strip, color to color.

12. Power line: from the ships panel is connected securely to the terminal strip (see wiring diagram of typical CRUISAIR system). Be sure the proper size circuit breaker of the time delay type is installed.

13. Copper tubes between the cooling unit and condensing unit are insulated separately and completely. (Only the large tube is insulated for cooling only systems).

14. Copper tubes and wire harness are secured to the boat throughout their length.

15. Condensing unit is securely mounted.

16. Flare joints at the condensing unit are made with forged nuts and they are tight and insulated.

17. Wire harness plug has the pump wires securely inserted. See Figure 3-5.

cruisair-fig3-5.gif (4566 bytes)

18. Wire harness plug is inserted securely into the polarized receptacle in the condensing unit.

19. Pump is piped so that the water system is self draining and self purging. (Applies to use of centrifugal Pump only).

20. Pump is installed below the water line. (Applies to use of centrifugal type pump only).

21. Water supply system is equipped with a seawater strainer.

22. Water hoses are at least single braid neoprene. NO PLASTIC HOSES SHOULD BE USED.

23. Separate overboard water discharge for each unit is located so water flow through each condenser can be visually checked.

24. Overboard water discharge fitting is 1" to 2" above the water line.

25. Inlet thru-hull fitting is no more than 6" from the keel, is ahead of the stuffing boxes and aft of the forward engine room bulkhead.

26. Cooling unit or units connected to any one condensing unit have been selected properly. The last numbers of the condensing unit model number (12 in the case of a WFA12) must be equal to the last numbers of the attached cooling unit (12 in the case of an EFB12). If several cooling units are connected to one condensing unit, the sum of the model number digits must equal the condensing unit model number digits.

B. Purging Pre-charged Systems:
CRUISAIR equipment can be supplied with a pre-charged condensing unit. These systems can be put into operation in the held without having to use special refrigeration tools or have specific knowledge of refrigeration practices. If the condensing unit is pre-charged, a green tag will be attached to the unit specifying the minimum and maximum length of tubing that can be used with the pre-charge contained in the unit. If the total tubing length is more or less, refer to Section IV-C for processing of field charged units. If all is in order, proceed as follows:

1. At the condensing unit, remove the red cover from the charging port on the 1/4" service valve located on the right hand front corner of the unit.

2. To this port, attach a 1# can of refrigerant 22 and position the can upside down.

3. Open the can valve 1/2 turn for 15 seconds and then close the can valve.

4. The connecting tubing is now pressurized and the flare joints can be checked for leaks with a leak detector or soap bubbles. If a flare leak is found, tighten the flare and recheck. If the leak persists, remake the flare. Re-pressurize the tubing and recheck for leaks until flare joints are determined to be without leaks.

5. Open the refrigerant can valve all the way.

6. Loosen the flare nut at the other condensing unit service valve and allow the refrigerant in the lines to bleed out completely. This will purge the tubes of all air and moisture.

7. As soon as all purging has stopped at the loosened flare nut, tighten the nut securely.

8. Remove the empty can of refrigerant and replace the red cap on the charging port securely.

9. Remove the service valve stem covers at the top of both service valves to expose the service valve stems.

10. Turn both stems fully counterclockwise.

11. Replace both stem covers tightly. The pre-charged system is now ready to be put into operation. See Section IV, D.

C. Processing Field Charged Systems:
CRUISAIR equipment can be supplied not pre-charged or a system may have to be recharged after the initial installation. In either case, proceed as follows:

1. Secure a refrigeration type vacuum pump and a set of refrigeration charging gauges and hoses suitable for use with high temperature refrigeration systems using refrigerant 22.

2. Pressurize the connecting copper tubing and check for leaks as outlined in Section IV B, paragraph 1 thru 4.

3. Remove the refrigerant can from the charging port and replace the red cap.

4. Remove the stem covers from both service valves.

5. Rotate the stems on both service valves all the way counterclockwise.

6. Rotate the stem of the 1/4" service valve one turn clockwise.

7. Remove the cap from the 1/4" service valve charging port. Connect a vacuum Pump and allow it to operate 30 minutes on a new system or longer if substantial moisture is suspected to be in the system. This is good refrigeration service practice.

8. Rotate the 1/4" service valve stem fully counterclockwise.

9. Remove the vacuum pump.

10. Remove the charging port cap from the other service valve.

11. Connect a set of charging gauges to the charging ports and to a source of refrigerant 22. Be sure to purge all air from the charging hoses with refrigerant before connecting the hoses.

12. Rotate both charging valve stems one turn clockwise.

13. Refer to Section IV-D and put the system in operation on the cooling cycle before proceeding.

14. Allow refrigerant 22 to enter the system through the left hand service valve until the suction pressure reaches the proper level. This can be determined from the charging curves on the back cover of this manual.

NOTE: Be sure to determine cooling water inlet temperature with a thermometer, not your finger.

15. Adjust the refrigerant charge to comply with the head and suction pressures as indicated on the charging curves.

When the system is operating properly on the cooling cycle, in warm weather, with the fan on high, the compressor should run warm to hot. The 3/8" or 1/2" suction copper tube and service valve should be cold and sweating. A warm suction service valve indicates too little gas. A cold compressor indicates too much gas.

D. General Operation:
All CRUISAIR systems have basically three controls:

(1) off-start-run switch,
(2) fan speed control switch and
(3) thermostat.

To put the system in operation, proceed as follows:

1. Set top knob on control switch assembly to "off".

2. Turn on main circuit breaker at ship's panel.

3. Turn thermostat (bottom knob on switch assembly,) fully clockwise if it is a warm day and you want cooling. Turn fully counterclockwise, if it is a cool day and you want heating.

4. Set the fan speed control to high (center knob).

5. Make sure the seawater inlet valve is open. See Item 2, Figure 3-3.

6. Turn the top control knob to "start." This will energize the seawater pump and cooling unit fan. Look over the side of the boat to make sure water is flowing from the overboard discharge. See Item 8, Figure 3-3.

7. Turn the top control knob to "run" or "cool" and the compressor will start to cool or heat, according to the way the thermostat (bottom knob) is adjusted.

8. To set the thermostat, allow the unit to operate until the area is cooled or heated to the desired temperature. At this point, turn the thermostat knob slowly toward its center position until it "clicks" once. The thermostat is now set to maintain a constant temperature.

9. Select the fan speed desired. When operating on the heat cycle, use low fan for 5 to 15 minutes until the unit begins to heat well. Then switch to medium fan. Do not use low or high unless the unit is turned off and restarted. When operating on the cooling cycle, use any fan speed desired, bearing in mind that the lower the fan speed, the less capacity the system has.

10. To turn the system off, return the top knob to the "off" position.
Fan Speed: Fan motors available for use in small air conditioning units are of the shaded pole type and are voltage sensitive. Our design uses 112 volts. At this voltage, fan speeds will be normal in low, medium and high. If the voltage on which you are operating is lower than 112 volts, fan speeds will be generally lower and system capacity will be slightly reduced. Under such circumstances, the use of low fan is not recommended.

If the operating voltage is high, fan speeds will be generally higher and there will be less difference between each speed. If you operate at predominately high voltage conditions and the high fan speeds are undesirable, a simple electrical modification to the cooling unit can be made by your dealer to slow the fan speed down overall.

For details see CRUISAIR component specification sheet covering the cooling unit you have.
The CRUISAIR heating system is a reverse cycle heat pump which derives its heat from the seawater being circulated through the condensing unit. When the water temperature drops to 40oF, the heat output is about 80% of maximum and with 36oF water, the heat output is very low. Be sure to consider this limitation when specifying or using a heat pump type heating system.

Thermostat
The thermostat serves to turn the compressor on and off. It has no control over the seawater pump and fan which run continuously.

NOTE: CRUISAIR systems call easily be wired so that the pump and/or fan is cycled with the compressor by the thermostat. For details see CRUISAIR component specification sheet.

Thermostats on CRUISAIR cooling and heating systems provide an automatic changeover from cooling to heating with a 3 1/2o F differential. If the thermostat has been set for cooling per Section IV, D7, rotating the thermostat further to the left will cause the unit to heat. If you rotate the thermostat further to the light it will cause the unit to cool. If the thermostat is left stationary, the unit will cycle from cooling to neutral if cooling is needed or it will cycle from neutral to heating if heating is needed.

MAINTENANCE

A. Cooling Unit:
The fan motor in the cooling unit has sealed bearings and no lubrication is needed. Switch contacts are of the self cleaning type and require no maintenance. At the beginning of each boating season, check the cooling unit condensate drains for total or partial obstruction by pouring a quart of water rapidly into the condensate drip tray. It should drain completely within 30 seconds. When the cooling unit was installed initially, a piece of screen wire should have been installed in the return air to the cooling unit. Locate this screen and clean it if a visible buildup of lint has collected. No "winterizing" is required on the cooling unit.

B. Condensing Unit:

The condensing unit has no exposed moving parts or bearings and needs no maintenance at all. The refrigeration circuit is hermetically sealed and is charged with oil at the factory. No oil should be added. The refrigerant 22 gas in the system is adequate for the life of the unit. The gas charge should not be changed or altered except in the event the unit was charged improperly in the original installation or unless a leak occurs which allows gas to escape from the system.

C. Seawater Pumping System:
If the seawater pump is the rubber impeller type, model PJ series, the impeller should be inspected after each 300 hours of operation and replaced if worn. If the seawater pump is the centrifugal type, model PM series, the pump itself needs no maintenance. The seawater system should be protected from debris by an inboard or outboard strainer. If an inboard strainer is used, inspect it often and clean it as required. The CRUISAIR cupro-nickel condensers are of the high flow velocity design and no scale buildup is experienced in salt water and only rarely in fresh water. In the winter, close the thru-hull seacock and loosen the screws on the pump head to allow water to drain from the pump. Remove the water hose at Point 5, Figure 3-3 and allow water to drain from the condensing unit. If preferred, the system can be pumped full of antifreeze of any type to prevent freezing.

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Note: each of these links below opens in a new window, close when done.
See Seawater pump wiring diagram

See typical wiring and plumbing diagram

See figure 3-4 unit application guide.
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