Reznor CAUA User manual

Revision: CAUA-COOLING-COIL (03-22) 166152-A
CASED COOLING COIL INSTALLATION FOR GAS-FIRED
INDOOR HEATER
Supersedes: I-CAUA-CC (04-15) PN166152R5
MODEL CAUA
Table 1. Cooling Coils
Model CAUA
Unit Size
Cased Cooling
Coil Model
ACU Unit
Size Option Description
150, 200 ACUA
060 C060 5-ton, single-circuit A or dual-circuit A (1/3–2/3) cased coil
072 C072 6-ton, single-circuit A cased coil
090 C090 7.5-ton, dual-circuit A (50/50 or 1/3–2/3) cased coil
250, 300 ACUB
090 C090 7.5-ton, dual-circuit A (50/50 or 1/3–2/3) cased coil
120 C120 10-ton, dual-circuit A (50/50 or 1/3–2/3) cased coil
150 C150 12-ton, dual-circuit A (50/50 or 1/3–2/3) cased coil
350, 400*
ACUC
120 C120 10-ton, dual-circuit A (50/50 or 1/3–2/3) cased coil
150 C150 12-ton, dual-circuit A (50/50 or 1/3–2/3) cased coil
180 C180 15-ton, dual-circuit A (50/50 or 1/3–2/3) cased coil
*The cased cooling coil for unit sizes 350 and 400 may include a factory-installed discharge plenum (option CD62). To install a cased cooling
coil with a discharge plenum, refer to these instructions plus the instructions in the CAUA-DISCH-PLENUM manual available at www.
reznorhvac.com.
NOTE: Installation should be done by a qualified agency in accordance with these instructions
and in compliance with all codes and requirements of authorities having jurisdiction.
GENERAL INFORMATION
•These instructions are for installing an optional cased cooling coil on a model CAUA heater (see Figure 1). The
coil may be ordered as either model ACU (A, B, or C) or as a C option. Thermostatic expansion valves selected
to match the coil are shipped loose for field-installation.
•Shipped with the heater is a package of parts required to install a heat section condensate drain. When the
application includes a cooling coil, installation of the heat section condensate drain is required.
•Refer to the installation manual provided with the heater for important safety information and for instructions to
install the heater. The heater should be in its final installation location without discharge ductwork before installing
the cooling coil.
•Refer to Table 1 to match model CAUA and ACU unit sizes with available cooling coils.
NOTE: All cooiling coils are for use with R-410A refrigerant.
Figure 1. Model CAUA with Optional Cooling Coil

2CAUA-COOLING-COIL (03-22) 166152-A
GENERAL INFORMATION—CONTINUED
Unpacking and Inspection
If, upon removing it from its crate, the unit has been found to have incurred any damage in shipment, document
the damage with the transporting agency and contact an authorized Factory Distributor. If you are an authorized
Distributor, follow the FOB freight policy procedures.
Pre-Installation Checklist
Check the rating plate for the specifications and electrical characteristics to be sure that they are compatible with
the installation.
Read these instructions and become familiar with the installation requirements. If you do not have knowledge of
local requirements, check with the local gas company or any other local agencies who might have requirements
concerning this installation.
Make preparations for necessary supplies, tools, and manpower. Installation should be done by an HVAC technician
qualified in refrigerant system installation.
Verify that the package of parts required to install the heat section condensate drain is either already installed
or at the job site.
Locate the thermostatic expansion valve(s) that are shipped loose. ACU unit size 060 has either one or two valves,
unit size 072 has one valve, and unit sizes 090–180 have two valves.
If a reducer is required to connect the thermostatic expansion valve to the distributor, the required reducers are
shipped with the valves.
Refer to Table 2 to verify that the thermostatic expansion valve(s) are correct for the installation.
Table 2. Thermostatic Expansion Valve (TXV) Kit Components and Connection Sizes
Cased
Cooling Coil
Kit PN
Component Distributor
Connection
on Coil
Liquid Line Connection*Suction Line
Tubing
Model Unit
Size
Evap
Coil
Reducer TXV Inlet** Outlet
Circuit
ABABABABABAB
PN*** Connection Size (Inches)
ACUA
060 258856 257328 216428 — 234052 — 5/8 — 5/8 — 7/8 — 7/8 —
258858 258846 —220552 220553 5/8 1/2 5/8 5/8 7/8
072 258857 257329 220555 — 7/8 — 5/8 — 7/8 — 7/8 —
090 258860 257538 216428 220554 5/8 5/8 7/8 7/8
258861 257330 — 216428 220553 234052 5/8 7/8
ACUB
090 258860 257539 216428 220554 5/8 5/8 7/8 7/8
258861 257331 — 216428 220553 234052 5/8 7/8
120 258862 257540 216428 234052 5/8 5/8 7/8 7/8
258863 257332 — 220553 220555 5/8 7/8 5/8 7/8
150 258864 257541 — 220555 7/8 5/8 7/8 7/8
258865 257333 216428 — 220554 220557 5/8 7/8 1-3/8 7/8
ACUC
120 258862 257542 216428 234052 5/8 5/8 7/8 1-3/8
258863 257334 — — 220553 220555 5/8 7/8 5/8 7/8 1-3/8 7/8
150 258864 257543 — — 220555 7/8 7/8 5/8 7/8 1-3/8
258866 257335 216428 216432 220554 220557 5/8 1-1/8 1-3/8 7/8
180 258867 257544 216432 220557 1-1/8 1-1/8 5/8 7/8 1-3/8
258868 257336 216428 216432 234052 220557 5/8 1-1/8 1-3/8 7/8
*Circuit A is bottom connection. Circuit B is top connection.
**Liquid line tubing size.
***Refer to Table 3 for specifications.

3
CAUA-COOLING-COIL (03-22) 166152-A
Dimensions
Table 3. Thermostatic Expansion Valve Kit Component Specifications
Evaporator Coil TXV
PN Row FH FL FPI PN Manufacturer's
Model No.
257328 2 20 28 10 220552 BBIZE-2
257329 2 20 28 12
257330 3 24 28 10
220553 BBIZE-3257331 2 24 42 12
257332 3 20 42 10
257333 3 24 42 12
220554 BBIZE-4257334 2 30 41 12
257335 3 27 41 10
257336 3 30 41 10
220555 BBIZE-6
257538 3 24 28 10
257539 2 24 42 12
257540 3 20 42 10
220557 BBIZE-8
257541 3 24 42 12
257542 2 30 41 12
257543 3 27 41 10
234052 BBIZE-5257544 3 30 41 10
258846 2 20 28 10
Figure 2. Cased Cooling Coil Dimensions (Refer to Table 4)

4CAUA-COOLING-COIL (03-22) 166152-A
Table 4. Cased Cooling Coil Dimensions
Unit
Size
Dimension (See Figure 2)
A B C D E F G H J K M N P Q U V
Inches (mm)
150,
200 27
(686)
38
(965) 23
(584)
36
(914) 21
(533)
16-1/2
(419) —8-1/2 (217) —
2-1/8
(54)
6
(152)
4
(102) —3-1/2 (89) 14-1/2
(368)
27
(686)
250,
300 50
(1270)
48
(1219)
16
(406)
13-5/8
(346)
8-5/8
(219)
6-1/4
(159)
5-1/8
(130)
3-5/8
(92)
3-1/4
(83)
2-3/4
(70)
41-1/4
(1048)
350,
400
32-5/8
(829)
36
(914)
34
(864)
20-1/2
(521)
17-1/4
(438)
9-1/4
(235)
7-3/4
(197)
4-1/4
(108)
5-3/4
(146)
4-1/4
(108)
3
(76)
27-1/2
(699)
39-7/8
(1013)
NOTE: Hole locations: suction lines = G × P for circuit A or F × Q for circuit B, liquid lines = J × N for circuit A or H × N for circuit A, drain = K × M.
GENERAL INFORMATION—CONTINUED
Dimensions—Continued
Weights
Table 5. Cased Cooling Coil Weights
CAUA Unit Size Cased Cooling Coil Model Option Pounds (kg)
150, 200 ACUA
C060 83 (38)
C072 86 (39)
C090 105 (48)
250, 300 ACUB
C090 110 (50)
C120 122 (55)
C150 140 (64)
350, 400 ACUC
C120 176 (80)
C150 180 (82)
C180 188 (85)
INSTALLATION
Install Cooling Coil on Top of Heater
NOTE: The heater must be level and should be in its final installed location before installing the
cased cooling coil. The coil fits over the discharge opening on the top of the heater.
1. If specified, place field-supplied gasket material on top of heater where cabinet surfaces will have contact.
2. Coil fits with line connection holes in front or rear of cabinet. Locate openings and determine most efficient
orientation, lift coil, and place it on top of heater. Because of cabinet design, there is no mechanical attachment
required between heater and cased cooling coil.
3. Verify that heater and coil cabinet are level.
Thermostatic Expansion Valve (TXV) Kit Installation
⚠ CAUTION ⚠
The TXV must be for R-410A refrigerant and must be sized to match the circuit. Failure to correctly
select and install the TXV(s) will prevent the system from operating properly and will void the
manufacturer’s warranty.
NOTE: For replacement parts information, including TXVs for R22 refrigerant, refer to the replace-
ment parts manual available at www.reznorhvac.com.
Ensure that the shipped-loose TXV kit components are correct for the installation and for each circuit in accordance
with Table 2 and with the unit rating plate. Install the TXV kit as follows:

5
CAUA-COOLING-COIL (03-22) 166152-A
NOTE: Refer to the TXV manufacturer's instructions for installation information including bulb
placement. When brazing, wet wrap the valve body but do not allow moisture to enter the tubing.
Braze with the flame pointed away from the valve.
1. Position outlet of circuit A TXV toward distributor connection in bottom liquid line.
2. If reducer is required, install it on distributor connection and TXV outlet. If there is no reducer, connect TXV outlet
to distributor connection.
3. Repeat steps 1 and 2 to install circuit B TXV in top liquid line.
NOTE: If there are two circuits, be sure to match the liquid line with the corresponding suction line.
4. After refrigerant lines are installed and before refrigerant charging, install TXV bulb:
a. Extend bulb from TXV to suction line.
b. Position bulb flat against surface of tubing and orient capillary tube as shown in Figure 3. Place bulb on straight
horizontal section of suction line as close as possible to evaporator coil outlet. If bulb must be vertical, line
must be descending.
NOTE: Never place the TXV bulb in a trap or downstream of a trap.
c. Secure bulb tightly. Bulb must have 100% contact with tubing.
d. Cover bulb with waterproof insulation.
Bulb at
3 o’clock
Bulb at
4 o’clock
Bulb at
8 o’clock
Bulb at
9 o’clock
12
3
6
9
Suction line
cross-section
Suction line
TXV bulb
Suction line
TXV bulb
Horizontal section
of suction line
(preferred location)
Vertical section of suction line
(descending flow only)
Capillary
tubing
from TXV
Capillary tubing from TXV
Field-supplied
equalizer tubing
Figure 3. TXV Bulb Installation (Applies to Both Circuits)

6CAUA-COOLING-COIL (03-22) 166152-A
INSTALLATION—CONTINUED
5. At short distance downstream from bulb, connect one end of field-supplied equalizer tubing to suction line—
preferably at location X (see Figure 4). If location X is not possible, location Y is acceptable as long as pressure
is essentially same as at X. Connect other end of field-supplied equalizer tubing to 1/4-inch ODF fitting on TXV
(see Figure 4).
TXV
Evaporator Coil in Model ACU or Option C
Cased Cooling Coil
TXV
Bulb
Suction Line
X
Y
Figure 4. Equalizer Line Installation (Applies to Both Circuits)
Heat Section Condensate Drain Line Installation
When a cooling coil is installed on a model CAUA heater, a heat section condensate drain line must be installed. Refer
to burner condensate drain kit installation instructions available at www.reznorhvac.com to install a condensate
drain line in the heat section.
Cased Cooling Coil Drain Line Installation
⚠ CAUTION ⚠
• An obstruction in the drain or a poorly-designed drain can cause the condensate pan to overflow.
Overflow could result in damage to the unit and/or building.
The cased coil has a 3/4-inch FPT drain connection (see location in Figure 2). Install the drain line as follows:

7
CAUA-COOLING-COIL (03-22) 166152-A
1. Pitch drain line at least 1/2 inch (13 mm) for every 10 feet (3 meters) of horizontal run.
2. Ensure that drain line does not interfere with access panels or doors.
3. Install drain trap in drain line. Determine drain trap dimensions as follows:
a. Dimension A (see Figure 5, DETAIL A) = 3 inches (76 mm) minimum.
b. Dimension B (see Figure 5, DETAIL A) = A + A/2.
Figure 5. Condensate Drain Trap Dimensions
⚠ CAUTION ⚠
• The design of the drain trap is important.
• Improper trap design accounts for some condensate drainage system failures, but incorrect
use and maintenance of condensate drain traps can also cause problems. The combination of
airborne particles and moisture in the air handler can result in algae formation in the drain pan
and traps. The traps must be cleaned regularly to avoid blockage that can slow or stop water
flow, resulting in backup into the system.
NOTE: If dimension B (see Figure 5, DETAIL A) is not tall enough, the water seal will not hold and
air will be drawn through the drain pipe into the unit. If the outlet leg of the trap is too tall, water
will back up into the drain pan. As condensate forms during normal operation, the water level in
the trap rises until there is a constant outflow.
4. Connect heat section condensate drain line tubing (refer to Heat Section Condensate Drain Line Installation
section) into cooling coil condensate drain line and continue into sanitary drain system.
5. Ensure that cleanout (see Figure 5, DETAIL B) is closed to prevent air from entering drain line.
NOTES:
• SEASONAL USAGE: At the beginning of the cooling season, inspect and clean the entire cooling
coil cabinet including the condensate drain pan.Thoroughly clean dirt, algae, grease, and other
contaminates. Inspect condensate drain pans, traps, and piping and fill traps with water to ensure
proper operation. During a wintertime shutdown of the cooling system, it may be desirable to
disconnect and remove all water from the traps and drains to prevent freeze damage. If local
building codes permit, traps may be filled with an antifreeze solution or piping may be designed
with freeze plugs or other freeze-protection methods such as a heat tape.
• YEAR-ROUND USAGE: Climates or applications with cooling requirements year-round require
more frequent inspections of the cooling coil cabinet and condensate drains. Depending on
climate, freeze-protection of traps may be required during non-cooling hours.
DETAIL A DETAIL B
CABINET
CABINET
CLEANOUT

Ductwork Installation
•This system requires both return air and discharge ductwork unless ordered with an option AVA2 inlet base and/
or an option CD discharge plenum.
•Install discharge ductwork to the top of the cooling coil cabinet (refer to dimensions D × E in Figure 2 for duct
flange dimensions.
•It is recommended that an optional mixing box with filters, an optional filter cabinet, or field-supplied filters be
installed in the inlet air duct.
Electrical Connections
The system is operated by 24V controls (see Figure 6). A separate 24V control transformer is required for the
condensing equipment controls. Refer to the 24V electrical requirements of the condenser manufacturer.
Figure 6. Typical Wiring Diagram for 24V Controls
NOTE: Refer to the installation manual provided with the heater for additional details on installing
ductwork and to complete the installation of the heating/cooling unit. Follow the instructions and
requirements of the model MASA or field-provided condensing unit to complete the cooling system.
Specifications and illustrations subject to change without notice or incurring obligations.
Latest version of this manual is available at www.reznorhvac.com.
©2022 Nortek Global HVAC LLC, O’Fallon, MO. All rights reserved.
CAUA-COOLING-COIL (03-22) 166152-A