INSTALLATION, OPERATION, AND MAINTENANCE OF CRUISAIR MARINE AIR CONDITIONING EQUIPMENT
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
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
(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
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)
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
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.
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 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.
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-purg ing
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
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
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
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 condens ing 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
17. Wire harness plug has the pump wires securely inserted. See Figure 3-5.
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
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
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
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
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
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
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
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
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
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
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.
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.
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.
Note: each of these links below opens in a new window, close when done.
See Seawater pump wiring diagram
See typical wiring and plumbing
See figure 3-4 unit