MRCOOL MAHM060CTA Installation Manual
The Signature Series is NOT designed for amateur installation. Installation SHOULD be performed by an authorized technician.
Please read this manual carefully before installation and keep it for future reference.
Owner & Installation
Manual
Signature Series
MAHM*CTA AIR Handler
The Signature Series is NOT designed for amateur installation. Installation SHOULD be performed by an authorized technician.
Please read this manual carefully before installation and keep it for future reference.
INSTALLATION INSTRUCTIONS
MAHM*CTA Series Air Handler
This manual must be left with the homeowner for future reference.
This is a safety alert symbol and should never be ignored. When you see this symbol on labels or in
manuals, be alert to the potential for personal injury or death.
Table of Contents
Shipping and Packing List ...........................................3
General........................................................................3
Requirements ..............................................................3
Installation Clearances ................................................4
Installation ...................................................................4
Condensate Drain........................................................7
Duct System and Filters ..............................................8
Brazing Refrigerant Lines............................................9
Sealing the Unit .........................................................12
Electrical Connections...............................................12
..............................16
Check-Out Procedures..............................................18
Operation...................................................................18
..........................................19
Repairing or Replacing Cabinet Insulation ................19
Professional Maintenance .........................................20
Use of Air Handler During Construction.....................20
......2
IMPORTANT INFORMATION FOR INSTALLER
This unit has a delay relay that delays the supply blower “ON” for 1 second and keeps the blower “ON” for 45
seconds on all fan and cooling demands. For more details, refer to page 18 for unit sequence of operation.
3 4
100%
2
1
1
SECOND
DELAY
Manufactured By
MRCOOL LLC
Hickory, KY 42051
Save these instructions for future reference
507787-01C mrcool.com Page 1 of 22
CFM
COOLING
DEMAND
100%
CFM
45
SECS
OFF
*P507787-C*1
(P) 507787-01C
MAHM*CTA
1 (25)
LINE VOLTAGE
INLETS
(Top and Left Side)
3/4
(19)
1 (25)
14-1/2
(368)
TOP VIEW
CIRCUIT
BREAKER
COVER
SUPPLY AIR
OPENING
C
B
1 (25)
LOW VOLTAGE
INLETS
(Top and Right Side)
2-3/8
(60)
4-3/8
(111)
LINE VOLTAGE
INLETS
(Top and Right Side)
LOW VOLTAGE
INLETS
(Either Side)
DETAIL OF PIPING PLATE
3/4 (19)
SUCTION
LINE
LIQUID
LINE
2-3/4
(70)
1-3/4
(44)
4-3/4
(121)
CONDENSATE
CONDENSATE
3-1/2
(89)
22
(559)
DRAINS (2)
(Horizontal)
DRAINS (2)
(Upflow and
Downflow)
AIR FLOW
A
PIPING
PLATE
1-1/8
(29)
D
OPENING
CONDENSATE DRAIN
PIPING PLATE (3)
(2-1/4 x 3-3/4)
FILTER
ACCESS
1-1/8
(29)
SUCTION
LINE
LIQUID
LINE
1/2
(13)
20-3/8
(518)
OPENING
FRONT VIEW SIDE VIEW
Dimensions
018 024 030 036 / 042 048 060
in. mm in. mm in. mm in. mm in. mm in. mm
A 43-1/2 1105 45-1/2 1156 47 1194 53-5/8 1362 55 1397 59-3/4 1518
B 18-1/2 470 18-1/2 470 18-1/2 470 21-1/2 546 21-1/2 546 21-1/2 546
C 16-1/2 419 16-1/2 419 16-1/2 419 19-1/2 495 19-1/2 495 19-1/2 495
D 16-1/4 413 16-1/4 413 16-1/4 413 19-1/4 489 19-1/4 489 19-1/4 489
1-1/8
(29)
507787-01Cmrcool.comPage 2 of 22
Shipping and Packing List
Package 1 of 1 contains:
Requirements
Check the air handler for shipping damage; if found,
immediately contact the last carrier. Check the unit rating
NOTE: Special procedures are required for cleaning
the all-aluminum coil in this unit. See Page 20 in this
instruction for information.
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, personal
injury or loss of life. Installation and service must be
performed by a licensed professional HVAC installer or
equivalent, service agency, or the gas supplier.
The Clean Air Act of 1990 bans the intentional venting
of refrigerant (CFCs, HCFCs and HFCs) as of July
1, 1992. Approved methods of recovery, recycling or
may be levied for noncompliance.
can result in back or other type of injury.
MAHM*CTA units include a factory-installed check/
capacities. These units must be installed as a part of
a matched system as outlined in the MAHM*CTA Product
These instructions are intended as a general guide and do
authorities having jurisdiction before installation.
pertaining to this type of equipment should be determined
as the instructions supplied in separate equipment, before
starting the installation.
In addition to conforming to manufacturer’s installation
instructions and local municipal building codes, installation
The
MAHM*CTA series air handler with all-aluminum coil is
designed for indoor installation only. As shipped, the unit
hand or right-hand air discharge applications. Electric
accessories are available and listed in the Product
This instruction is intended as a general guide and does
authorities having jurisdiction before installation.
sheet metal edges can result in personal injury. Take
and protective clothing.
(NFPA) standards: “Standard for Installation of Air
Conditioning and Ventilation Systems” (NFPA No. 90A)
and “Standard for Installation of Residence Type Warm Air
Heating and Air Conditioning Systems” (NFPA No. 90B).
All models are designed for indoor installation only. The
must conform to the requirements of the National Electrical
Code, ANSI/NFPA No. 70 (latest edition) in the United
Local authorities having jurisdiction should be consulted
before installation is made. Such applicable regulations
or requirements take precedence over the general
instructions in this manual.
the Installation of Warm Air Heating and Air-Conditioning
Systems (latest edition).
The air handler is shipped from the factory completely
connection of the duct system.
507787-01C mrcool.com Page 3 of 22
Do not remove the cabinet knockouts until it has been
the installation.
conditions. Consider required clearances, space, routing
requirements for refrigerant line, condensate disposal,
information.
materials and vapors, such as gasoline,
that heating elements are at least 18 inches
instructions can result in death, explosion,
•
they exit the conduit opening. Sealant is required to
prevent air leakage into, and condensate from forming
inside of, the air handler, the control box, and on the
electrical controls.
• This unit is approved for installation clearance to
combustible material as stated on the unit rating
plate. Accessibility and service clearances must take
precedence over combustible material clearances.
• The air handler must be installed so that free access
control compartment.
bottom to form a return air plenum. It may also be installed
single-story buildings.
Excessive condensation may occur if the unit is installed
unconditioned space, apply sealant around electrical
Apply sealant on the inside of the cabinet at the
electrical controls.
This unit is approved for installation clearance to
combustible material as stated on the unit rating
plate. Accessibility and service clearances must take
precedence over combustible material clearances.
The air handler must be installed so that free access is
compartment.
When a MAHM*CTA
be:
• 320 square inches for -018 and -024 models;
• 360 square inches for -030 and -036 models;
• 450 square inches for -042 thru -060 models
determine if the open area meets the minimum open area
listed above.
If a return air plenum is used, the return air grille should be
the opening, there must be adequate clearance around the
and controls in an insulated galvanized steel factory-
•
humid space.
• If installed in an unconditioned space, sealant should
cabinet.
For ease in installation, it is best to make any necessary
place.
Refrigerant Metering Device
MAHM*CTA
expansion valve or an RFC device.
507787-01Cmrcool.comPage 4 of 22
1. The air handler must be supported on the bottom only
frame.
2.
horizontal drain pan.
NOTE: The horizontal drain pan is not required in
3. Place the unit in the desired location and slope unit.
Connect return and supply air plenums as required
Right-Hand Discharge
1.
connections.
2. With access door removed, remove drain line plugs to
install drain lines.
3.
end of the unit and level from front to back of unit (see
Figure 6).
4.
4. Install units that have no return air plenum on a stand
air return.
HORIZONTAL DRAIN PAN
(MUST BE REMOVED)
UP-FLOW /
DOWN-FLOW
DRAIN PAN
Figure 1.
Horizontal Applications
AIR FLOW
Drains
RIGHT‐HAND DRAINS
PLUGS
Figure 2.
5. If the unit is suspended, the entire length of the cabinet
must be supported. If you use a chain or strap, use a
piece of angle iron or sheet metal attached to the unit
air plenums as required.
ANGLE IRON OR SHEET
METAL
MAXIMUM 1/2"
LONG SCREW
E
ANCE 4 IN. (102 MM)
AIR FLOW
When removing the coil, there is a possibility of danger
of equipment damage and personal injury. Be careful
FRONT WEIVDNEWEIV
in right- or left-hand applications. The coil may tip into
the drain pan once it is clear of the cabinet. Support the
Figure 3. Suspending Horizontal Unit
Left-Hand Air Discharge
NOTE: When the unit is installed in horizontal applications,
codes.
NOTE:
air discharge horizontal applications. Adequate support
1. Remove access panels and the corrugated padding
corrugated padding.
2. Pull the coil assembly from unit. Pull off the horizontal
drain pan.
panels if installing in the horizontal position.
3. Remove the drain plugs from back drain holes on
horizontal drain pan and reinstall them on front holes.
507787-01C mrcool.com Page 5 of 22
NOTE:
into the coil end plate engaging holes. Misaligned
After removal of drain pan plug(s), check drain hole(s)
to verify that drain opening is fully open and free of any
debris. Also check to make sure that no debris has
fallen into the drain pan during installation that may plug
up the drain opening.
4. Rotate drain pan 180º front-to-back and install it on the
opposite side of the coil.
5.
6. Remove plastic plug from left hole on coil front end
seal and reinstall plug in back hole.
TOP CAP ROTATED TO
CORRECT POSITION
CABINET
SUPPORT
DRAIN PAN
REINSTALLED
HERE
90º
BEND
TOP CAP SCREWS
DRAIN PAN
SHIPPING
LOCATION
8.
support rail as illustrated.
9. Install the horizontal shield (-060 model) on the front
edge of the horizontal drain pan as illustrated in Figure
5.
NOTE:
of humid air.
10. Knock out drain seal plate from access door. Secure
11. Flip access door and replace it on the unit.
12.
end of the unit. Connect return and supply air plenums
13. If suspending the unit, it must be supported along the
entire length of the cabinet. If using chain or strap,
use a piece of angle iron or sheet metal attached to
REINSTALLED HERE REMOVED FROM HERE
COIL SHOWN IN UPLOAD POSITION FOR EASY CONVERSION
TOP
CAP
90º
BEND
———— DRAIN PLUGS ————
ALIGN HOLES WITH
HOLES IN COIL END
PLATE. STARTING WITH
THE ROUND HOLES ON
THIS END.
BACK COIL END SEAL
Figure 4.
7.
back coil end plates. The top cap has a 45º bend on
one side and a 90º bend on the other. The 90º bend
must be on the same side as the horizontal drain
pan as illustrated in Figure 4.
illustrated in Figure 3. Connect return and supply air
NOTE:
kit.
If electric heat section with circuit breakers (ECBA25) is
installed in a MAHM*CTA unit in a downflow application, the
circuit breakers must be rotated 180° to the UP position.
See ECBA25 installation instructions for more details.
DOWN-FLOW RAIL FRONT EDGE OF HORIZONTAL
Figure 5.
DRAIN PAN
507787-01Cmrcool.comPage 6 of 22
Condensate Drain
in the condensate drain lines (primary and auxiliary,
through the drain lines into the air supply.
Sloping The Unit
THIS CORNER SHOULD BE 5/8" (+/- 1/8") HIGHER
THAN DRAIN CORNER
pipe to the outside of the building, is required in all
DRAIN CORNER
pan. In some localities, local codes may require a
secondary drain pan for any horizontal installation.
ABOVE
FINISHED
SPACE?
YES
NOTE — WHEN A AIR HANDLER IS LOCATED
ABOVE A FINISHED SPACE THE SECONDARY
DRAIN PAN MUST HAVE A LARGER FOOTPRINT
THAN THE AIR HANDLER.
SECONDARY
DRAIN PAN
WHEN A COIL IS LOCATED ABOVE A FINISHED SPACE, A
3/4” (19.1MM) SECONDARY DRAIN LINE MUST BE:
CONNECTED TO SECONDARY DRAIN PAN
OR
CONNECTED TO THE OVERFLOW DRAIN OUTLET OF
THE AIR HANDLER DRAIN PAN.
TRAPS MUST BE DEEP ENOUGH TO OFFSET MAXIMUM STATIC DIFFERENCES —
GENERALLY, TWO INCHES (51MM).
1
P-TRAP 49P66 REQUIRES A LARGER INSTALLATION SPACE THAN THE J-TRAP 91P90.
2
PIPE NIPPLE PROVIDED IN BAG ASSEMBLY - SCH 80, 3/4” I. D. X 5” - 34K7401 (1): CUT THE PIPE IN HALF AND USE IT TO ROUTE THE MAIN DRAIN.
ALWAYS RUN AN OVERFLOW DRAIN LINE. IF NOT POSSIBLE TO
ROUTE OVERFLOW DRAIN LINE, INSTALL LOW VOLTAGE
OVERFLOW SWITCH KIT. WIRE KIT TO SHUT DOWN
COMPRESSOR PER INSTRUCTIONS.
COMPACT OVERFLOW SWITCH WITH 3/4” FEMALE SLIP INLET
NO
AND MALE ADAPTER, TWO PART DESIGN FOR USE WHERE
OBSTRUCTIONS PREVENT DIRECT THREADING
AIR HANDLER DRAIN PAN
OVERFLOW
DRAIN
OVERFLOW DRAIN LINE
PART #
X3169
MAIN
DRAIN
MAIN
DRAIN
CUT TO
REQUIRED
LENGTH
PROVIDED
PIPE NIPPLE
SIDE VIEW
2
Figure 6. Sloping the Unit for Proper Drainage
VENT MUST EXTEND
ABOVE HEIGHT OF
COIL DRAIN PAN BY
TWO INCHES (51MM)
CLEAN OUT
PRESS IN
(DO NOT GLUE)
1” X 3/4” X 3/4”
REDUCING
TEE WITH
PLUG
1
P-TRAP
49P66, J-TRAP #
91P90 OR ANY
PVC SCH 40 P- OR
J-TRAP 3/4”
FOR NEGATIVE PRESSURE COILS (BLOWER
AFTER COIL) TRAPS ARE REQUIRED ON ALL
DRAIN LINES CONNECTED TO COIL.
VENT
TRAP DEPTH
LEVEL PLANE
2”
(51MM)
DRAIN LINE SHOULD
SLOPE A MINIMUM OF
ONE INCH PER 10
FEET (25MM PER 3
METERS)
TO APPROVED
DRAIN
Figure 7.
507787-01C mrcool.com Page 7 of 22
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