Reznor CAUA User manual

Revision: CP-CAUA-GC (04-21) 170635-A
GAS CONVERSION KIT INSTALLATION FOR GAS-FIRED INDOOR
HEATER
Supersedes: CP-CAUA-GC (01-18) PN170635R9
MODEL CAUA
GENERAL INFORMATION
The gas conversion kits in these instructions are for model CAUA heaters equipped with specific single-stage or
two-stage gas valves. The kits are for operation at sea level. When converting a unit with a two-stage valve (option
AG2), check for the valve manufacturer. If the unit has a two-stage White-Rodgers valve, a new two-stage gas valve
is required.
Gas Valve Identification
In order to verify which conversion kit is compatible with your heater, it is necessary to know the type of gas valve on
the heater. Refer to the unit rating plate for the complete model number of the heater. Also, refer to the manufacturer’s
name and number found on the gas valve. Match the model number of the valve to the one listed in the kit—if different,
contact your manufacturer representative to select and verify parts required for gas conversion.
Important Safety Information
Please read all information in this manual thoroughly and become familiar with the capabilities and use of your
appliance before attempting to operate or maintain this unit. Pay attention to all dangers, warnings, cautions, and
notes highlighted in this manual. Safety markings should not be ignored and are used frequently throughout to
designate a degree or level of seriousness.
DANGER: A danger statement describes a potentially hazardous situation that if not avoided, will result in severe
personal injury or death and/or property damage.
WARNING: A warning statement describes a potentially hazardous situation that if not avoided, can result in severe
personal injury and/or property damage.
CAUTION: A caution statement describes a potentially hazardous situation that if not avoided, can result in minor
or moderate personal injury and/or property damage.
NOTE: A note provides important information that should not be ignored.
⚠ DANGER ⚠
FIRE OR EXPLOSION HAZARD
• Failure to follow safety warnings exactly could result in serious injury, death, or property
damage.
• Improper installation,adjustment,alteration, service,or maintenance can cause serious injury,
death, or property damage.
• Installation and service must be performed by a qualified installer, service agency, or the gas
supplier.
• Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or
any other appliance.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in your building.
• Leave the building immediately.
• Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s
instructions.
• If you cannot reach your gas supplier, call the fire department.
DO NOT DESTROY. PLEASE READ CAREFULLY. KEEP IN A SAFE PLACE FOR FUTURE REFERENCE.

2CP-CAUA-GC (04-21) 170635-A
GENERAL INFORMATION—CONTINUED
Important Safety Information—Continued
⚠ DANGER ⚠
• The conversion kit is to be selected and installed by a qualified service person in accordance
with these instructions and in compliance with all codes and requirements of authorities having
jurisdiction. Failure to follow instructions could result in death, serious injury ,and/or property
damage. The qualified agency performing this work assumes responsibility for this conversion.
• Improper installation,adjustment,alteration,service,or maintenance can cause property damage,
injury, or death. Read the installation, operation, and maintenance instructions thoroughly before
installing or servicing this equipment.
• FOR YOUR SAFETY: Do not store or use gasoline or other flammable vapors and liquids in the
vicinity of this or any other appliance.
• The gas burner in this gas-fired equipment is designed and equipped to provide safe, complete
combustion. However, if the installation does not permit the burner to receive the proper supply
of combustion air, complete combustion may not occur. The result is incomplete combustion,
which produces carbon monoxide, a poisonous gas that can cause death.
• Safe operation of indirect-fired gas burning equipment requires a properly-operating vent system
that vents all flue products to the outside atmosphere. FAILURE TO PROVIDE PROPER VENTING
WILL RESULT IN A HEALTH HAZARD THAT COULD CAUSE SERIOUS PERSONAL INJURY OR
DEATH.
• If installed as a separated-combustion system, install either the horizontal or vertical combustion
air/vent system illustrated in the heater installation manual,using the concentric adapter supplied.
All installations must comply with the combustion air requirements in the installation codes
and instructions. Units installed in a confined space must be supplied with air for combustion
and ventilation as required by code and in the heater installation manual. Combustion air at the
burner should be regulated only by manufacturer-provided equipment. NEVER RESTRICT OR
OTHERWISE ALTER THE SUPPLY OF COMBUSTION AIR TO ANY HEATER. MAINTAIN THE VENT
SYSTEM IN PROPERLY-OPERATING CONDITION.
NOTE: In Canada, gas conversion shall be carried out in accordance with the requirements of the
Provincial Authorities having jurisdiction and in accordance with the requirements of CSA-B149.1
and .2 installation code.
CONVERSION KIT SELECTION
NOTES:
• Refer to Table 1 for a list of natural gas (NG) to propane (LP) conversion kit components.
• Refer to Table 2 for a list of propane to natural gas conversion kit components.
• Refer to Table 3 for burner orifices included in the gas conversion kits (for sea-level operation
only) and for replacement orifices for high-elevation (>2,000 feet) installations.
• Refer to Table 4 for a list of additional components required for converting a unit equipped with a
two-stage White-Rodgers (WR) gas valve. When converting a unit with a two-stage valve (option
AG2), check for the valve manufacturer. If equipped with a Honeywell (HW) valve, select the kit
listed in Table 1 and Table 2.
• All kits include the quantity of orifices required for the largest size of heater. Extra burner orifices
may not be returned for credit.

3
CP-CAUA-GC (04-21) 170635-A
Table 1. Natural Gas to Propane Conversion Kit Components
Unit
Size
Kit
PN Component*Description PN Gas Valve (Model No.
All
NG to LP spring kit HW #393691 for single-stage valve VR8105, VR8205, or VR8305 98720
—Tape Conversion 64391
Disk Propane 37752
150 269833
NG to LP spring kit HW #396221 for single-stage valve VR8215 260605
Single-stage (HW
# VR8304M2816 ,
#VR8205M1130, or
#VR8215S1263)
or
two-stage (HW
#VR8204Q2418)
Spring regulator kit HW # 396021 for two-stage valve 197207
200 269834
NG to LP spring kit HW #396221 for single-stage valve VR8215 260605
Spring regulator kit HW # 396021 for two-stage valve 197207
250 170815 Spring regulator kit WR #F920659 for single-stage WR valve 82524
Single-stage (WR
#36C68-452,
#36H32-441, or HW
#VR8305M4009)
or
two-stage (HW
#VR8304Q4404)
HW #396021 for two-stage valve 197207
300 170816 Spring regulator kit WR #F920659 for single-stage WR valve 82524
HW #396021 for two-stage valve 197207
350 170817 Spring regulator kit WR #F920659 for single-stage WR valve 82524
HW #396021 for two-stage valve 197207
400 170818 Spring regulator kit WR #F920659 for single-stage WR valve 82524
HW #396021 for two-stage valve 197207
*Burner orifices are include in each kit. Refer to Table 3 for orifice PN, size, and quantity.
Table 2. Propane to Natural Gas Conversion Kit Components
Unit
Size
Kit
PN Component*Description PN Gas Valve (Model No.
All
LP to NG spring kit HW # 394588 for single-stage valve VR8105, VR8205, or VR8305 98721
—Tape Conversion 64391
Disk Natural Gas 1401
150 269833
LP to NG spring kit HW #396222 for single-stage valve VR8215 261651 Single-stage (HW
#VR8204M1018,
#VR8205M1148, or
#VR8215S5215)
or
two-stage (HW
#VR8304Q4412)
Spring conversion kit HW #3906025 for two-stage valve 197208
200 269834
LP to NG spring kit HW #396222 for single-stage valve VR8215 261651
Spring conversion kit HW #3906025 for two-stage valve 197208
250,
300 170810 Spring conversion kit WR #92-0656 for single-stage WR valve 82525 Single-stage (WR
#36C68-325,
#36H32-442, or HW
#VR8305M4819)
or
two-stage (HW
#VR8304Q4412)
HW #396025 for two-stage valve 197208
350 170811 Spring conversion kit WR #92-0656 for single-stage WR valve 82525
HW #396025 for two-stage valve 197208
400 170812 Spring conversion kit WR #92-0656 for single-stage WR valve 82525
HW #396025 for two-stage valve 197208
*Burner orifices are include in each kit. Refer to Table 3 for orifice PN, size, and quantity.
Table 3. Burner Orifices
Installation
Elevation (Feet)
Installation
Location Unit Size Natural Gas Propane Quantity
PN Size PN Size
0–2000 US or Canada
150 164866 2.10 mm 97359 1.25 mm 8
200
11833 #44
11830 #55 10
250 97359 1.25 mm 13
300 11830 #55 15
350 11835 #37 9789 #53 12
400 45870 #38 61653 1.55 mm 14
2001–3000 US
150 84853 #47 97359 1.25 mm 8
200
38678 #45
11830 #55 10
250 97359 1.25 mm 13
300 11830 #55 15
350 45870 #38 11834 #54 12
400 45871 #39 9789 #53 14

Table 3. Burner Orifices
Installation
Elevation (Feet)
Installation
Location Unit Size Natural Gas Propane Quantity
PN Size PN Size
2001–4500 Canada
150 40414 #48 63003 1.20 mm 8
200
38678 #45
11830 #55 10
250 63003 1.20 mm 13
300 11830 #55 15
350 45871 #39 11834 #54 12
400 11792 #41 61652 1.45 mm 14
3001–4000 US
150 84853 #47 63003 1.20 mm 8
200
38678 #45
11830 #55 10
250 63003 1.20 mm 13
300 11830 #55 15
350 45871 #39 11834 #54 12
400 87391 #40 9789 #53 14
4001–5000 US
150 40414 #48 63003 1.20 mm 8
200
38678 #45
11830 #55 10
250 63003 1.20 mm 13
300 11830 #55 15
350 45871 #39 11834 #54 12
400 11792 #41 61652 1.45 mm 14
5001–6000 US
150 40414 #48 63003 1.20 mm 8
200
16590 #46
39658 #56 10
250 63003 1.20 mm 13
300 39658 #56 15
350 87391 #40 11834 #54 12
400 11792 #41 61652 1.45 mm 14
6001–7000 US
150 40414 #48
39658 #56
8
200
84583 #47
10
250 13
300 15
350 11792 #41 11834 #54 12
400 84437 #42 61652 1.45 mm 14
7001–8000 US
150 39651 #49 63922 1.15 mm 8
200
84583 #47
39658 #56 10
250 63922 1.15 mm 13
300 39658 #56 15
350 84437 #42 11834 #54 12
400 14
8001–9000 US
150 39651 #49 63922 1.15 mm 8
200
40414 #48
39658 #56 10
250 63922 1.15 mm 13
300 39658 #56 15
350 84437 #42 11830 #55 12
400 11828 #43 11834 #54 14
CONVERSION KIT SELECTION—CONTINUED
—Continued
Table 4. Components Required for Converting Unit with Two-Stage White-Rodgers Gas Valve
Unit
Size
Two-Stage Gas Valve Brass
Plug
Reducing Bushing
(3/4- to 1/2-Inch)*
Natural Gas Propane
150 177396
177398 107367
37385
200
250
177397 —
300
350
400
*Used only for natural gas to propane conversions.
4CP-CAUA-GC (04-21) 170635-A

INSTALLATION
Install the conversion kit in accordance with the following steps. Ensure that the kit (refer to Table 1 or Table 2) is
correct for the size of the heater being serviced. Heater component locations are shown in Figure 1.
Figure 1. Heater Components
NOTE: Conversion using these kits will not alter the input rate. Refer to the rating plate on the unit
for the input rate and other appropriate information.
1. Remove gas supply and electrical power:
a. Turn OFF gas supply at shutoff valve upstream of combination gas valve.
b. Turn OFF electrical power.
c. Open control access panel.
2. Install regulator spring kit:
⚠ WARNING ⚠
Regulator spring kits are not interchangeable. Each kit must be used only in the model and type of
gas valve for which the kit is designated.Verify compatibility before installing the regulator spring kit.
a. Select regulator spring kit that corresponds with gas valve on heater. All gas conversion kits include one or
two regulator spring kits for single-stage valve and one regulator spring for two-stage valve. Other included
regulator spring kits will not be used.
b. Install regulator spring kit in accordance with gas valve manufacturer’s instructions (included with regulator
spring kit).
NOTE: Depending on when the unit was manufactured, there will be either two or three burner
covers. If two, there will be right and left covers that extend over the front of the unit. If three, there
will be right and left covers and a separate front cover.
5
CP-CAUA-GC (04-21) 170635-A

6CP-CAUA-GC (04-21) 170635-A
INSTALLATION—CONTINUED
NOTE: When converting a unit with a two-stage White-Rodgers gas valve the spring kits in the
conversion kit will not be used and the gas valve requires replacing.
3. For units with White-Rodgers two-stage gas valve, replace valve:
a. Disconnect gas valve wires from existing valve. Label wires for correct reconnection.
b. Disconnect existing gas valve from gas supply line and remove valve.
NOTE: Because the unit does not have a pilot, the pilot port on the replacement two-stage White-
Rodgers gas valve needs to be plugged using a brass plug.
c. Using brass plug listed in Table 4, plug port labeled “pilot” on replacement valve listed in Table 4.
⚠ WARNING ⚠
The operating gas valve is the primary safety shutoff. The gas supply line must be free of dirt or
scale before connecting the valve.
d. Connect inlet side of replacement gas valve to gas supply line. Do not connect valve to manifold.
e. Connect gas valve wires labelled in step 3b to valve.
f. Ensure that all gas valve connections are in accordance with unit wiring diagram and valve manufacturer’s
instructions.
4. Replace burner orifices:
a. Remove all burner covers and disconnect manifold from valve.
b. Remove screws that secure manifold assembly and remove manifold assembly from heater.
c. Carefully remove existing burner orifices.
d. For all conversions, select replacement burner orifices in accordance with Table 3.
⚠ WARNING ⚠
Do not attempt to drill burner orifice. Use factory-supplied orifice only.
e. Install replacement burner orifices.
⚠ CAUTION ⚠
Ensure that the manifold is positioned properly with relation to the burner rack.
f. Install manifold assembly in heater and secure using screws removed in step 4b.
g. Attach conversion disk to heater near gas valve.
h. Connect manifold to valve. For natural gas to propane conversion of unit size 150 or 200 with White-Rodgers
two-stage gas valve, use reducing bushing listed in Table 4 to connect valve.
i. Install burner cover removed in step 4a.
5. Perform leak test:
a. Turn ON gas supply at shutoff valve upstream of combination gas valve.
b. Check between shutoff valve and combination gas valve for gas leaks using commercial leak-detecting fluid
or rich soap and water solution. Leaks are indicated by presence of bubbles.
c. If leak is detected, tighten connection. If leak cannot be stopped by tightening connection, replace part(s).
d. When no leaks are detected, turn OFF gas supply at shutoff valve upstream of combination gas valve.
6. Restore electrical power and gas supply:
a. Turn ON electrical power.
b. Turn ON gas supply and relight heater in accordance with instructions on heater.

7
CP-CAUA-GC (04-21) 170635-A
c. Recheck all manifold connections for gas leaks in accordance with step 5.
7. Measure and adjust manifold (outlet) pressure:
⚠ WARNING ⚠
Manifold gas pressure must never exceed 3.5 IN WC for natural gas or 10 IN WC for propane.
Incorrect inlet pressure could cause excessive manifold gas pressure.
a. Ensure that inlet (supply) pressure is in accordance with Table 5 and determine correct manifold (outlet)
pressure (refer to Table 5).
Table 5. Gas Pressure Requirements
Natural Gas Propane
Minimum Maximum Minimum Maximum
Inlet (Supply) Pressure (IN WC)
5.0*14.0 11.0*14.0
Single-Stage and Two-Stage High-Fire Two-Stage Low-Fire
Natural Gas Propane Natural Gas Propane
Manifold (Outlet) Pressure (IN WC)
3.5 10.0 1.8 5.0
*Or as stated on the unit rating plate.
b. Turn knob or switch on top of valve to OFF to prevent flow to gas valve.
NOTE: A manometer (fluid-filled gauge) is recommended rather than a spring-type gauge due to
the difficulty of maintaining the calibration of a spring-type gauge. Use a water column manometer
that is readable to the nearest tenth of an inch.
c. Connect manometer to 1/8-inch output pressure tap on valve (see Figure 2).
SINGLE-STAGE VALVES
TWO-STAGE VALV E
REGULATOR
SCREW
INLET
PRESSURE
TA P
1/8" OUTLET
PRESSURE
TA P
1/8" OUTLET
PRESSURE
TA P
INLET
PRESSURE
TA P
REGULATOR
SCREW
INLET PRESSURE TA P
1/8" OUTLET PRESSURE TA P
HIGH-FIRE
REGULATOR SCREW
LOW-FIRE
REGULATOR SCREW
Figure 2. Gas Valves

INSTALLATION—CONTINUED
⚠ CAUTION ⚠
DO NOT bottom out the gas valve regulator screw. This can result in excessive overfire and heat
exchanger failure due to unregulated manifold pressure.
d. To measure/adjust high fire pressure on single-stage or two-stage valve:
(1) Turn knob or switch on top of valve to ON.
(2) If pressure is out-of-range, remove cap from regulator screw (see Figure 2) and adjust pressure in accordance
with Table 5 by turning regulator screw IN (clockwise) to increase pressure or OUT (counterclockwise)
to decrease pressure.
e. To measure/adjust low fire pressure on two-stage valve:
(1) Disconnect wire from HI terminal on gas valve.
(2) Remove cap from low-fire regulator screw (see Figure 2) and adjust pressure in accordance with Table
5 by turning regulator screw IN (clockwise) to increase pressure or OUT (counterclockwise) to decrease
pressure.
(3) Reconnect wire to Hi terminal on gas valve.
⚠ WARNING ⚠
In the event of improper ignition, wait at least 5 minutes before attempting to relight the heater.
f. Turn up thermostat and cycle burner once or twice to properly seat adjustment spring in valve.
g. Recheck outlet pressure. When pressure corresponds to Table 5, disconnect manometer and install cap on
regulator screw.
h. Check for leakage at 1/8-inch outlet pressure tap fitting. Correct as necessary.
8. Operate heater for at least one complete cycle to check for proper operation. Observe main burners for
complete flame carryover.
9. Fill out conversion tape and adhere to clean, dry surface near unit rating plate.
10. Close control access panel.
Specifications and illustrations subject to change without notice or incurring obligations.
©2021 Nortek Global HVAC LLC, O’Fallon, MO.
All rights reserved.
CP-CAUA-GC (04-21) 170635-A