Mermaid MARINE AIR CONDITIONING, MARINE AIR CONDITIONER Installation Manual

MERMAID MARINE AIR

CONDITIONING

INSTALLATION

&

OPERATIONS GUIDE

Mermaid Manufacturing of Southwest Florida, Inc.

2651 Park Windsor Drive, Suite 203

Fort Myers, FL 33901

[phone] [phone]

Fax [phone]

E-mail:

Web site:

[e-mail]

http://www.mmair.com

TABLE OF CONTENTS

SECTION 1

A. Introduction to Mermaid

SECTION 2

A. Air Conditioner Installation
B. Operation

SECTION 3

A. Digital, Programmable Thermostat

SECTION 4

A. Introduction
B. Installation

SECTION 5

A. Maintenance
B. Winterization

(OVERVIEW)

(INSTALLATION and OPERATION)

(OPERATION and PROGRAMMING)

(PUMP RELAY BOX)

(MAINTENANCE and WINTERIZATION)

SECTION 6

A. Theory of Operation
B. Trouble Shooting

(THEORY of OPERATION and TROUBLE SHOOTING)

FIGURES:

1. Typical Ducting and Venting Scheme

2. Operational Block Diagram

3. Typical Cooling Water Installation
4a. Wiring Diagram "Cool Only" Models
4b. Wiring Diagram "Electric Heat and Cool" Models
4c. Wiring Diagram "Reverse Cycle Heat and Cool" Models

5. Typical Bleed Off Valve Installation

SECTION 1

(OVERVIEW)

A. Introduction:

Congratulations!! You have just purchased one the most dependable Marine Air
Conditioners on the market today, a MERMAID.

Mermaid supplies pleasure boat owners, custom boat builders, yacht brokers, boat dealers
and marinas around the world with their marine air conditioning needs.

Mermaid air conditioners are manufactured to the highest of quality standards using only
top of the line components and materials assembled by long-term technicians. All of our
air conditioners are modularized, self contained, prewired, precharged and mounted on a
solid foundation of stainless steel. All of our air conditioning components, such as the
evaporator, compressor and condensing coil are manufactured in the USA. All electrical
parts are standard refrigeration components and are available across the entire country,
and around the world. Any four wire 24Volt digital thermostat will operate any standard
Mermaid air conditioner. Don’t forget to see our NEW flush mount digital controller

on our website –

Our standard electrical control box does not contain any printed circuit boards or solder.
All electrical connections are "snap on" color coded wires, making part replacement
simple and fast. The electrical box can be unplugged for ease of assembly and service
and the entire installation can be accomplished with standard shop tools. Our upgraded
controller uses state of the art electonics eliminating any contactor or relay noises.

Our warranty is also unsurpassed. For the first 5 years, the Mermaid factory
warranty covers all issues with your air unit. After 5 years, any certified air
conditioner technician, marine, household or commercial, can service any Mermaid
air conditioner model.

www.mmair.com.

SECTION 2

(INSTALLATION and OPERATION)

A. AIR CONDITIONER INSTALLATION:

First, and of foremost importance, the air conditioner and electrical box must be installed
in a non-explosive, dry environment. SEE THE FOLLOWING WARNING.

WARNING

IF THE AIR CONDITIONER OR ELECTRICAL BOX ARE PLACED IN AN
EXPLOSIVE ENVIRONMENT OR EXPOSED TO AN EXPLOSIVE ENVIRONMENT
OR EXPLOSIVE MATERIALS, EXPLOSION COULD OCCUR RESULTING IN
SERIOUS INJURY OR DEATH AND/OR DESTRUCTION OF THE BOAT. THIS
COMPONENT DOES NOT MEET FEDERAL REQUIREMENTS FOR IGNITION
PROTECTION. DO NOT INSTALL IN SPACES CONTAINING GASOLINE
ENGINES, TANKS, LPG/CPG CYLINDERS, REGULATORS, VALVES OR FUEL
LINE FITTINGS. FAILURE TO COMPLY MAY RESULT IN INJURY OR DEATH.

Typical unit mounting spots are under the vee berth, under settee seats, in hanging
lockers, in cabinets or in outside dry lazzeretts and sail lockers. The selected spot must
accommodate the following eight requirements. Everything must fit in and/or be
accessible to the selected spot:
(a) The physical size of the unit and electrical box.
(b) Water in and out hoses.
(c) Electrical power cable for the unit and pump connections.
(d) Air ducting and air splitters.
(e) Mounting of the return air grill to insure the proper volume of return air.
(f) Access to the high pressure switch.
(g) Condensation removal.
(h) Thermostat installation and wiring.

IMPORTANT

READ THE ENTIRE INSTALLATION INSTRUCTIONS BEFORE YOU

COMMIT TO CUTTING OR DRILLING ANY HOLES. REMEMBER

" HOLES ARE FOREVER". MEASURE, MEASURE, THEN MEASURE AGAIN

BEFORE PICKING UP ANY TOOL WITH A SHARP EDGE.

IMPORTANT

LEAVE AMPLE EXCESS OF HOSE, WIRE AND DUCTING WHEN ROUTING

INTO THE AIR CONDITIONER MOUNTING COMPARTMENT TO ALLOW

FOR FINAL POSITIONING OF THE AIR CONDITIONER AFTER ALL

INSTALLATION TASKS ARE COMPLETED.

We will now address each of the above eight requirements in detail:

1. Installing the Air Conditioner Unit:

AIR CONDITIONER DIMENSIONS

UNIT BTU WIDTH LENGTH HEIGHT
5,200 Cool Only 11.5 Inches 15 Inches 11.5 Inches
5,200 Reverse Cycle 12 Inches 18 Inches 11.5 Inches
6,500 11.5 Inches 16 Inches 11.5 Inches
9,000 11.5 Inches 16 Inches 11.5 Inches
12,000 13 Inches 19.75 Inches 13.75 Inches
16,500 13.5 Inches 19.75 Inches 13.75 Inches
24,000 17 Inches 23 Inches 13.75 Inches

The air conditioner needs to be mounted in an area where it will physically fit, as well as
accommodate a properly sized return air grill and any ducting or splitters (Wyes) which
would be attached to the air output collar. In addition, you need to insure there is space
for the water hoses to be connected.

The air conditioner must be securely mounted on a flat surface. If the sole of the boat
(cabin floor) cannot accommodate the size of the air conditioner base plate, a mounting
shelf or platform must be built. Typically the shelf will be made from 3/4 inch marine
grade plywood which can be either fiberglassed or mechanically attached to the boat’s
sole or superstructure. Never screw directly into the hull.

When attaching the unit to the sole of the boat, the superstructure or a fabricated
mounting shelf, always make absolutely positive that the length of the screws being
used to mount the unit will not engage the hull. If there is any question as to whether the
hull may be compromised, an alternative mounting method must be used or another
mounting spot must be located.

The electrical box, unlike the air conditioner, can be mounted in any attitude. It is
attached to the air conditioner by a detachable 40 inch electrical cable allowing it to be
mounted above the unit, on a side wall or bulkhead and, if needed, in a totally inverted
position.

IMPORTANT

IT IS NOT UNCOMMON IN AIR CONDITIONING SYSTEMS FOR

CONDENSATION LINES OR PANS TO BECOME BLOCKED OVER

PROLONGED USE. WHEN SELECTING THE ELECTRICAL BOX

MOUNTING SPOT MAKE SURE THAT IT IS NOT LOCATED WHERE

CONDENSATION WATER CAN COME IN CONTACT WITH IT SHOULD THE

CONDENSATION WATER OVER FLOW ITS PAN. NEVER PLACE THE

ELECTRICAL BOX BELOW THE AIR CONDITIONING UNIT.

WARNING

IF CONDENSATION WATER CONTACTS THE ELECTRICAL BOX

ELECTRICAL SHORTING COULD OCCUR CAUSING FIRE WHICH COULD

RESULT IN SERIOUS INJURY, DEATH AND/OR DESTRUCTION OF THE

BOAT.

We suggest that once you are satisfied that the unit and electrical box, along with all of
the other items required in the air conditioner compartment will fit, that you remove the
air conditioning unit and electrical box or cover them completely until all holes and
construction in the compartment are completed and the area cleanly vaccuumed.

2. Cooling water in and out:

All central marine air conditioning and heating units are water cooled. Cooling water is
provided to the air conditioner via a foot scoop, sea cock, water strainer and pump
assembly all of which are mounted below sea level. Typically the sea cock, water
strainer and pump are installed remotely to the air conditioner (SEE FIGURE 3).

Water In:

Generally, in power boats, the sea cock will be installed in the engine compartment. In
sail boats, because of their more uniform draft characteristics, it is usually installed under
a settee seat or some other compartment more convenient to the air conditioner.

Water is then routed to the air conditioner from the pump via 5/8 inch marine water hose
(also known as ½” I.D. hose) where it is connected to the air conditioner condensing
coil's "water in" connection. Make sure that space is allowed around the unit to make
this connection. The water hose is easily kinked, restricting water flow. If needed, use a
hose barb 90 degree fitting to eliminate any kinking. (These can be found at any pvc
supply store).

An additional length of 5/8 inch marine hose (again, ½” I.D.) is connected to the
condensing coil "water out" connection. Cooling water passes through the condensing
coil and routed through this hose to the "water out" thru-hull fitting which will be
installed above water level in the side of the boat’s hull (SEE FIGURE 3).

IMPORTANT

THE SEA COCK, WATER STRAINER AND WATER PUMP MUST BE

INSTALLED BELOW SEA LEVEL. THE SEA WATER PUMP IS NOT SELF

PRIMING AND RELIES ON WATER SEEKING ITS OWN LEVEL ALONG

WITH THE HYDRAULIC PRESSURE OF THE BOAT TO ATTAIN PRIMING

OF THE PUMP.

WARNING

BEFORE DRILLING THE MOUNTING HOLE FOR THE SEA COCK THE

ENTIRE BOAT MUST BE OUT OF THE WATER. DRILLING THE SEA COCK

MOUNTING HOLE WITH THE BOAT IN THE WATER COULD CAUSE

EXTREME FLOODING AND SINK THE BOAT OR CAUSE SEVERE WATER

DAMAGE TO EQUIPMENT IN THE BOAT.

IMPORTANT

WHEN SELECTING THE SPOT FOR THE SEA COCK, BEFORE DRILLING

THE HOLE, MAKE SURE THAT THE PUMP AND WATER STRAINER CAN

BE INSTALLED IN THE SAME ADJACENT AREA AND REMAIN BELOW SEA

LEVEL. ALSO CHECK THE OPERATION OF THE BALL VALVE SHUT OFF

HANDLE ON THE SEA COCK FOR ANY POSSIBLE INTERFERENCE ONCE

INSTALLED.

When selecting your sea cock mounting spot, you should also try to select a spot where
the pump and water strainer are a maximum distance of 2 feet from the sea cock. We
realize that in some boats it is not possible to incorporate the two foot rule. However,
remember the closer you keep these three items together, the fewer pump priming
problems will be experienced.

Once you are sure that all components will fit in the spot selected and remain below sea
level and the boat is totally out of the water, you are ready to cut the sea cock mounting
hole. (SEE WARNING ABOVE)

IMPORTANT

BEFORE CUTTING YOUR SEA COCK MOUNTING HOLE CHECK THE

OUTSIDE HULL IN THE AREA YOU WILL BE CUTTING TO MAKE SURE

THAT THERE ARE NO RIBS OR OTHER HULL VARIATIONS WHICH WILL

NOT ALLOW THE SEA COCK FOOT SCOOP TO MOUNT FLAT AGAINST

THE HULL. IF THERE IS ANY CONCERN, WHAT-SO-EVER, DRILL A

SMALL PILOT HOLE FIRST WHICH CAN BE EASILY SEALED IF

INTERFERENCE EXISTS.

If you are using a sea cock assembly furnished by Mermaid, we recommend that a 1-1/16
inch hole saw be used to make this hole. If you are using a sea cock purchased
elsewhere, you must use the appropriate hole saw for that specific sea cock.

IMPORTANT

DRILL THE 1-1/16” SEA COCK MOUNTING HOLE AND PILOT HOLE AT

THE SAME ANGLE AS THE HULL. THIS WILL INSURE THAT THE FOOT

SCOOP LIES FLAT AGAINST THE HULL.

Once the sea cock hole is drilled, inspect the hole to determine if your boat has a
"corded" hull. That is, a hull not of solid fiberglass, but two layers of fiberglass
separated by balsa or foam. When not properly sealed, “cording” acts like a wick,

absorbing sea water into the hull. If the hull is "corded," obtain a fiberglass sealing kit
from your local marine supplier to seal the cording before installing the sea cock,
eliminating the possibility of "water logging" your hull. This is also true of water out
thru-hulls.

IMPORTANT

FAILURE TO SEAL A “CORDED” HULL MAY RESULT IN SERIOUS

DAMAGE TO THE BOAT’S STRUCTURE.

Note: The threads on the foot scoop end about 3/8 of an inch from the actual foot scoop.
If after drilling the hole for the foot scoop you discover that your hull is thinner than 3/8
inch, you will need to reinforce the hull with a 6” x 6” pad to “shim up” to insure the nut
tightens correctly. We usually use ¾ inch marine grade plywood to fashion the pad.
Apply fibreglass on both sides of the pad and affix to the inside of the hull. After the
fiberglass has cured, assuming that you had already drilled the hole for the foot scoop
through the hull, then drill through the pad from the outside of the hull to insure proper
alignment through the pad and hull. Do not attempt to drill through the pad from the
interior of the boat.

Before installing the sea cock, apply a bead of marine sealant around the foot scoop and
mounting post. We recommend "3 M" 5200 brand or a sealant brand of equivalent
quality.

Insert the foot scoop up into the boat with the scoop intake facing toward the bow
(foreword) and secure it to the hull with (2) 1/4 inch flat head s/s screws. We
recommend that the screw holes be predrilled with the appropriate size drill bit to
eliminate cracking of the outer gelcoat of the hull. When drilling the holes, take care not
to drill through the hull. Use a hand held screwdriver to eliminate stripping the hole out.
These screws are intended only to keep the foot scoop from turning under the boat when
the inside fastening nut is tightened down.

Inside the boat, attach the bronze retaining nut to the sea cock threaded post. Using an
appropriate size tool or slip jaw pliers, tighten the nut to the hull snugly to insure that it
will seal against the hull. After tightening the nut completely, cover it with a thick coat
of marine sealant from the post out to about 1 inch from the nut onto the hull.

Now that the foot scoop is mounted, the ball valve (shut off valve) can be attached.
Generously coat the foot scoop post threads with marine sealant and screw the ball valve
onto the post. After the ball valve is fully tightened on the post, check the action of the
shut off arm to make sure it can be fully opened and closed without interference with the
boat structure, the water hoses when they are attached or any other obstruction. If
interference is encountered, turn the ball valve on the post to a position that allows proper
operation. CLOSE THE VALVE, REPEAT, CLOSE THE VALVE!

To connect your water hose you will need a 90 degree "thread to hose barb" fitting and a
¾ inch “closed end nipple.” Using 3M 5200, thread the ¾ inch “closed end nipple” to

the seacock, then fasten the 90 degree thread to hose barb, with 5200 on to the ¾ inch
nipple. The “closed end nipple” is the bronze threaded pipe open on either end.

The water strainer and pump can now be mounted, but first you must get each component
fully assembled and ready to mount. The water strainer and pump brackets must be
securely mounted on a flat surface. Do not mount on the sole of the boat (cabin floor). If
a nearby bulkhead cannot accommodate the size of the mounting brackets, a mounting
shelf or platform must be built. Typically the shelf will be made from 3/4 inch marine
grade plywood which can be either fiberglassed or mechanically attached to the boats
sole or superstructure. Never screw directly into the hull.

When attaching the mounting brackets to the superstructure or a fabricated mounting
shelf, always make absolutely positive that the length of the screws being used to mount
the bracket will not engage the hull. If there is any question as to whether the hull may
be compromised, an alternative mounting method must be used or another mounting spot
must be located.

The Water Strainer:

If you are using a Mermaid furnished water strainer, it will come with (2) 3/4 inch thread
to hose barb hose fittings. Attach these fittings to the strainer using an ample amount of
marine sealant on the threads. Again, if you are using a Mermaid strainer, locate the
strainer mounting bracket. This is the bracket with a large hole in it. Unscrew the plastic
bowl from the strainer body and place the strainer body in the hole. Replace the plastic
bowl on the strainer body to lock the strainer in the bracket. This is meant to be a loose
fit to facilitate cleaning when the strainer is dirty.

Water will flow from the sea cock through the strainer into the inlet of the pump. Ideally,
the strainer and pump will be mounted so the water flow is at a slight upward grade to
help eliminate air locks. Once you have settled on the mounting locations of the strainer
and pump, attach each of their mounting brackets with (2) 1/2 inch s/s pan head screws.
Note that the strainer is directional. Take notice of the stamped arrow on the top of the
strainer when installing and insure the arrow is pointed toward the flow of water to the
air conditioner unit

Ideally, the pump should be mounted with the external 5/8” water discharge (the line that
goes TO the air conditioner) pointed vertically. However, there is an alternative position.
The pump can be mounted with the external 5/8” water discharge on the side. To
accomplish this successfully, it is IMPERATIVE to have the actual pump discharge at
the highest level. In this position, the external 5/8” discharge will be located on the
upper right corner of the pump with the ¾” intake facing you. In this alternative position,
the pump will still operate as originally designed. Failure to follow either of these
recommendations will void any warranty with the pump.

Never screw the pump directly to the hull. If a stringer or other structure is not
handy, you may have to fiberglass a mounting board to the hull to accept the
mounting screws.

Note: If you are supplying cooling water to more than one air conditioner a larger
GPH pump is required. Follow the mounting instructions furnished with the larger
pump. Also a “tee fitting” must be used on the discharge side of the pump to run
cooling water to each unit.

Using the appropriate length of the 3 feet of 3/4 inch red stripe marine hose and (2) s/s
hose clamps per connection, connect the sea cock, water strainer and pump together.

The Pump:

IMPORTANT
ON DUAL AIR CONDITIONER INSTALLATIONS, AN IN-LINE SHUT OFF
VALVE MUST BE INSTALLED IN EACH OF THE “WATER IN” LINES TO

ALLOW OPERATION OF EITHER AIR CONDITIONER IF ONE UNIT IS

REMOVED FOR SERVICE.

WARNING

ALL HOSE CONNECTIONS MUST BE SECURED USING TWO (2)

STAINLESS STEEL HOSE CLAMPS. FAILURE TO DOUBLE CLAMP ALL

HOSE CONNECTIONS MAY RESULT IN A HOSE DISCONNECTING WHICH

COULD CAUSE FLOODING DAMAGE AND /OR SINKING OF THE BOAT.

DAMAGE TO THE AIR CONDITIONER FROM EXCESSIVE AND

RECURRENT LEAKING DUE TO FAILURE TO DOUBLE CLAMP ALL

CONNECTIONS WILL VOID THE WARRANTY.

The 5/8 inch blue stripe water hose (or black reinforced hose – deluxe kits) and the pump
power cord may now be routed to the air conditioner compartment. If the power cord
that is permanently attached to the pump is not long enough to be routed to the air
conditioner compartment it must be extended using 16 gauge boat power cable. Cut off
the connector on the end of the pump power cord (if present) and splice in the 16 gauge
boat power cord. Appropriate electrical splicing must be used and the connection must
be water proof and secured well above the bilge water level to insure that the connection
will always remain dry. We have provided a piece of heat shrink tubing to ensure proper
insulation after connectors are applied.

WARNING

FAILURE TO KEEP THIS ELECTRICAL CONNECTION DRY COULD CAUSE

FIRE AND DESTRUCTION OF THE BOAT.

Note: Loss of prime on the water pump is a common occurrance. An optional
"Bleed Off " valve is available that aids in regaining pump prime. If you are using
this option, it must be installed at this stage of the installation at the output of the

pump (SEE FIGURE 5). Remember, all water hose connections must be secured
using double stainless steel clamps.

To install the bleed off valve, attach a short length of blue tracer hose to the water-out on
the pump and secure the bleed off valve on the other end of the hose. Attach the blue
tracer hose that you are running up to the air conditioner unit to the other end of the bleed
off valve. Close the bleed off valve. At each connection point, use two stainless steel
hose clamps to properly secure the attachment.

WARNING

AFTER INSTALLING "BLEED OFF" VALVE, MAKE SURE VALVE IS IN THE

"OFF POSITION". THAT IS, THE POSITION WHERE WATER CANNOT

FLOW INTO THE BILGE. FAILURE TO CLOSE THIS VALVE WILL RESULT

IN FLOODING WHEN THE BOAT IS PLACED BACK INTO THE WATER
POSSIBLY CAUSING SERIOUS WATER DAMAGE OR SINKING OF THE

BOAT.

After cutting off the three prong plug, temporarily tape the pump power cord to the end
of the water hose and route both items together to the air conditioner compartment (See
Following Note). Secure both items along the way at (1) to (2) foot intervals to
eliminate sagging or kinking due to boat or wave action. We will connect the cable and
hoses to the air conditioner later in the installation.

Note: If you are using a single pump to supply cooling water to two air conditioners,
you must install a Pump Relay Box. Before running pump power cable please see
Section 3 entitled "Pump Relay Box".

Water Out:

The "water out" thru-hull can be mounted any place on the boat’s hull that is a
minimum of (6) inches above the water line. If using a Mermaid supplied thru-hull
fitting, the required hole size is 1-1/16 inches so the same hole saw used for the "water
in" sea cock can be used. Typically the "water out" thru-hull will be mounted close to
the air conditioner to eliminate the extra work of having to route the water hose in
difficult places.

The water line on the outside of the hull will give a good base line to determine the lower
limit of the hole location. If your boat is new or kept high and dry, you will have to place
it in the water to determine the water line. Once you know the water line you can
determine where on the inside of the boat you can drill, staying above the water line and
out of view. This hole should always be drilled from the inside of the boat. Once you
have settled on a location for the hole, check outside again to insure you will be above
water level and that you will be clear of any outside ribs or other interference which will
not allow the outside lip of the fitting to lay flat against the hull. Always drill a pilot

hole and check outside before committing the larger hole.

When installing the thru-hull fitting apply an ample amount of marine sealant to the
outside lip of the fitting and its mounting post. If possible, have someone hold the
outside of the fitting to keep it from turning when you attach the retaining nut from the
inside. Be careful not to over tighten the nut. Use two (2) s/s hose clamps to attach the
hose to the thru-hull fitting. Route this hose into the air conditioner compartment where
it will eventually be connected to the condensing coil "water out" fitting.

3. Electrical Power:

Both the air conditioner and pump require 115 vac, 60 hertz power to operate. (220v
models are available) This power is obtained from the master 115 vac Circuit Breaker
Panel in the boat. Power is routed from this panel to the air conditioner. The air
conditioner will then supply power to the pump as required.

WARNING

BEFORE PROCEEDING FURTHER, CHECK TO INSURE THAT ALL 120 VAC

POWER HAS BEEN DISCONNECTED FROM THE BOAT AND CIRCUIT

BREAKER PANEL. FAILURE TO DO SO COULD CAUSE ELECTRICAL

SHOCK RESULTING IN SERIOUS INJURY OR DEATH

Using 12 gauge boat power cable, beginning on the inside of the Main Circuit Breaker
Panel, route the cable to the air conditioning compartment. Leave ample excess before
cutting to allow for positioning of the unit’s electric box at time of final hook up.
Connection of this cable to the air conditioner electrical box will be covered later.

At the circuit breaker panel locate a blank hole and install a 20 amp circuit breaker of the
same style as those breakers currently in the panel. Note that all of the breakers are
connected together on one side by either a buss bar or individual jumper wires. Connect
the new breaker in the same manner. Remove about 12 inches of the outer insulation
from the end of the boat cable to expose the inner wires. This cable contains (3) inner
insulated wires which are "BLACK", "WHITE" and "GREEN' in color. Using the
appropriate wire connectors, as those currently used in the panel, connect the wires as
follows: "BLACK" to the remaining terminal on the circuit breaker, "WHITE" to the
buss bar connecting all "WHITE" wires together and the "GREEN" to the buss bar
connecting all "GREEN" wires together. Included in the installation kit, if you purchased
that option, is a small Mermaid A/C sticker. Place this on your breaker panel to properly
denote the air conditioner circuit breaker. The Main Circuit Breaker Panel can now be
closed up.

FOR 220V UNITS THAT HAVE A 4 WIRE SYSTEM WITH RED, BLACK,

WHITE, AND GREEN WIRES, THE FOLLOWING APPLIES:

BLACK GOES TO BLACK (HOT)

RED GOES TO WHITE (NEUTRAL)

GREEN GOES TO GROUND

WHITE GETS CUT OFF AND NOT USED