Reznor UBX Series Owner's manual

Revision: UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
UNIT HEATER INSTALLATION/OPERATION/MAINTENANCE
Supersedes: UBX-UBZ-UDX-UDZ-IOM (01-22) 1034344-B
MODEL UBX: STANDARD POWER VENT BLOWER TYPE
MODEL UBZ: SEPARATED-COMBUSTION BLOWER TYPE
MODEL UDX: STANDARD POWER VENT FAN TYPE
MODEL UDZ: SEPARATED-COMBUSTION FAN TYPE
⚠ 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.
• Be sure to read and understand the installation, operation, and service instructions in this
manual.
• 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 phone remote from the building. 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.

2UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
TABLE OF CONTENTS
GENERAL INFORMATION ................................................................... 3
References .............................................................................. 3
Important Safety Information................................................................. 4
Certification .............................................................................. 4
Warranty ................................................................................ 4
Installation Codes ......................................................................... 5
Unit Location ............................................................................. 5
Heater Throw............................................................................. 5
Mounting Height Requirements............................................................... 7
Hazards of Chlorine........................................................................ 7
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Clearances .............................................................................10
Weights ................................................................................10
Combustion Air Requirements ..............................................................11
Acoustical Considerations..................................................................12
Technical Data ..........................................................................12
INSTALLATION ...........................................................................16
Unpacking and Inspection..................................................................16
Pre-Installation Checklist...................................................................16
Heater Suspension .......................................................................17
Suspension of Heater with Downturn Nozzle .................................................18
Suspension of Heater Using CK10 Hanger Kit................................................18
Suspension of Heater Using Option CK22 Hanger Kit ..........................................18
Heater Suspension Using Field-Supplied Threaded Rods.......................................19
Piping Connections .......................................................................19
Gas Supply Pressure ...................................................................19
Gas Supply Piping .....................................................................19
Supply Piping Connections ..............................................................20
Electrical Connections.....................................................................21
CONTROLS ..............................................................................23
Pressure Switch .........................................................................23
High Temperature Limit Control .............................................................25
Flame Rollout Switch (UDX Model Unit Sizes 030–125)...........................................25
Interlock Door Switch (UBZ and UDZ Models) ..................................................25
Main Operating Gas Valve .................................................................25
Fan Motor ..............................................................................25
Venter Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Thermostat Options.......................................................................26
Circuit Board (DSI Control Module)...........................................................26
OPERATION .............................................................................27
Pre-Startup Checklist .....................................................................27
Startup.................................................................................27
Operating Sequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Vent System Testing ......................................................................31
Post-Startup Checklist.....................................................................32
ADJUSTMENTS...........................................................................32
Pressure Switch Replacement ..............................................................32
Measure and Adjust Manifold (Outlet) Gas Pressure .............................................33
Measure and Adjust Manifold Gas Pressure—Elevation ≤2,000 Feet (≤610 Meters) ..................33
Measure and Adjust Manifold Gas Pressure—Elevation >2,000 Feet (>610 Meters) ..................35

3
UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
TABLE OF CONTENTS—CONTINUED
MAINTENANCE...........................................................................37
Service Checklist.........................................................................37
Maintenance Procedures ..................................................................37
Burner Maintenance ....................................................................37
Burner Orifice Maintenance ..............................................................40
Heat Exchanger Maintenance ............................................................40
Ignition System Maintenance .............................................................40
Maintenance of Fan Motor, Fan Blades, and Fan Guard ........................................41
Venter Motor and Wheel Assembly Maintenance .............................................42
Operating Gas Valve Maintenance ........................................................43
Pressure Switch Maintenance ............................................................43
High Temperature Limit Control Maintenance ................................................43
Flame Rollout Switch Maintenance (Model UDZ Unit Sizes 030–125 Only) .........................44
Interlock Door Switch Maintenance (Models UBZ and UDZ Only).................................44
Transformer Maintenance ...............................................................44
Disconnect Switch Replacement (Models UBZ and UDZ Only)...................................44
Vent or Vent/Combustion Air System Maintenance ............................................44
TROUBLESHOOTING ......................................................................44
Unit Troubleshooting Using DSI Control Module.................................................44
General Troubleshooting...................................................................46
INSTALLATION RECORD (TO BE COMPLETED BY INSTALLER)...................................48
GENERAL INFORMATION
•This unit heater has been tested for capacity and efficiency so as to provide many years of safe and dependable
comfort providing it is properly installed and maintained. With regular maintenance, this unit will operate satisfactorily
year after year. Abuse, improper use, and/or improper maintenance can shorten the life of the appliance and
create unsafe hazards.
•To achieve optimum performance and minimize equipment failure, it is recommended that periodic maintenance
be performed on this unit. The ability to properly perform maintenance on this equipment requires certain tools
and mechanical skills.
•This manual applies only to the models listed. Accessories referenced may not apply to all models.
References
Both this installation/operation manual and the appropriate venting instructions are shipped with the heater.Verify that
the literature is correct for the heater being installed. If either manual is missing or incorrect, contact your Distributor
before beginning installation.
Table 1. Related Technical Manuals Available from Factory Distributor
Type Form PN*
Replacement parts UBX-UBZ-UDX-UDZ-RPL 1034346
Venting instructions** UBX-UDX-VENTING 1034631
UBZ-UDZ-VENTING 1034632
Vertical louver kit installation UBX-UBZ-UDX-UDZ-UEZ-CD1 1036173
Downturn nozzle kit installation UBX-UBZ-UDX-UDZ-UEZ-CD2,3,4,5 1036421
Duct flange kit installation UBX-UBZ-CD9 1036171
Polytube adapter kit installation UBX-UBZ-CD11 1036422
Ceiling suspension kit installation UDX-UDZ-CK22 1037006
Gas conversion kit installation UBX-UBZ-UDX-UDZ-GC 1034364
Vent/combustion air kit installation OPT-CC2-CC6 205892
Relay kits for multiple heater control OPT-CL31-CL32 102247
Heat exchanger gasket kit installation UBX-UBZ-UDX-UDZ-UEZ-HX 1037154
*Also available at www.reznorhvac.com.
**BOTH this installation manual and the correct venting instructions are REQUIRED for the installation of this unit heater.

4UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
GENERAL INFORMATION—CONTINUED
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.
⚠ WARNING ⚠
• Gas-fired appliances are not designed for use in hazardous atmospheres containing flammable
vapors or combustible dust,in atmospheres containing chlorinated or halogenated hydrocarbons,
or in applications with airborne silicone substances.
• Should overheating occur, or the gas supply control system fail to shut off the flow of gas, shut
off the manual gas valve to the unit before shutting off the electrical supply.
• Do not use this appliance if any part has been under water. Immediately call a qualified service
technician to inspect the appliance and replace any gas control that has been under water.
• Installation should be done by a qualified agency in accordance with these instructions. The
qualified service agency installing this heater is responsible for the installation.
• This appliance is not intended for use by persons with reduced physical, sensory, or mental
capabilities or lack of experience and knowledge, unless they have been given supervision or
instruction concerning use of the appliance by a person responsible for their safety.
• Children should be supervised to ensure that they do not play with the appliance.
Certification
•Unit sizes 030, 045, 060, 075, 100, and 125 are design-certified by the Canadian Standards Association for use in
residential, industrial, and commercial installations. Utility heaters certified for residential use are intended for the
heating of non-living spaces that are attached to or part of a structure that contains space for family living quarters.
They are not intended to be the primary source of heat in residential applications or to be used in sleeping quarters.
•Unit sizes 150, 175, 200, 225, 250, 300, 350, and 400 are design-certified by the Canadian Standards Association
for use in industrial and commercial installations only.
•All models and unit sizes are available for use with either natural or propane gas. The type of gas, the gas input
rate, and the electrical supply requirement are shown on the heater rating plate. Check the rating plate to verify
that the heater is appropriate for the installation site.
Warranty
Refer to the limited warranty form in the literature bag provided with the unit. The warranty is void if:
•Wiring is not in accordance with the diagram furnished with the heater.
•The unit is installed without proper clearance to combustible materials.
•A fan model is connected to a duct system or if the air delivery system is modified.

5
UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
Installation Codes
•These units must be installed in accordance with local building codes. In the absence of local codes, in the United
States, the unit must be installed in accordance with the National Fuel Gas Code, ANSI Z223.1. A Canadian
installation must be in accordance with the CSA B149 Installation Codes. These codes are available from CSA
Information Services, 1-800-463-6727. Local authorities having jurisdiction should be consulted before installation
is made to verify local codes and installation procedure requirements.
•Installations in aircraft hangars should be in accordance with ANSI/NFPA No. 409 (latest edition), Standard for
Aircraft Hangars. Installations in public garages should be in accordance with ANSI/NFPA No. 88A (latest edition),
Standard for Parking Structures. Installations in repair garages should be in accordance with ANSI/NFPA No. 88B
(latest edition), Standard for Repair Garages. In Canada, installations in aircraft hangars should be in accordance
with the requirements of the enforcing authorities, and in public garages, in accordance with CSA B149 codes.
•If the heater is being installed in the Commonwealth of Massachusetts, installation must be performed by a licensed
plumber or licensed gas fitter.
Unit Location
⚠ CAUTION ⚠
• Unit heaters should not be used in an application where the heated space temperature is below
40°F (4°C). Operating under low ambient conditions may cause condensation to form in the heat
exchanger.
• Do not locate the heater where it may be exposed to water spray, rain, or dripping water.
•Refer to the venting instructions provided with the unit for venting requirements.
•Refer to the following sections of this manual to determine where to suspend the heater: Heater Throw, Mounting
Height Requirements, Hazards of Chlorine, Dimensions, Clearances, Weights, Combustion Air Requirements,
and INSTALLATION.
Heater Throw
Figure 1 shows throw patterns for fan model units. Table 2 and Table 3 list throw distances for standard, adjustable
horizontal louvers on heaters suspended at varying mounting heights. The louver angles listed are relative to the
top of the heater. The throw pattern changes with the addition of optional vertical louvers and/or downturn nozzles.
Z = Distance at which air velocity drops below 50 feet (15.2 meters) per minute
Figure 1. Heater Throw Patterns (Refer to Table 2 and Table 3)

6UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
GENERAL INFORMATION—CONTINUED
Heater Throw—Continued
Table 2. Heater Throw Distances with Standard Horizontal Louvers at Mounting Heights of 5 to 18 Feet
Distance*
Louver
Angle
Distance*
Louver
Angle
Distance*
Louver
Angle
Distance*
Louver
Angle
Distance*
Louver
Angle
Distance*
Louver
Angle
Distance*
Louver
Angle
H
X Y Z X Y Z X Y Z X Y Z X Y Z X Y Z X Y Z
Unit Size
030 045 060 075 100 125 150
5 6 14 30 −21° 7 16 40 −20° 8 18 45 −16° 9 20 57 −14° 9 20 59 −18° 10 22 65 −14° —
8 7 13 26 −39° 9 16 37 −34° 10 18 42 −29° 12 22 54 −25° 11 21 56 −28° 12 23 63 −24° 13 24 73 −26°
10 6 11 22 −52° 9 15 33 −43° 10 17 39 −37° 12 22 52 −32° 12 20 52 −36° 13 24 60 −30° 14 24 69 −32°
12 — 8 12 27 −55° 10 16 34 −46° 12 21 48 −39° 11 19 47 −44° 14 23 57 −36° 14 24 64 −39°
14 — 9 14 29 −56° 12 19 44 −46° 11 17 42 −51° 14 22 53 −43° 14 22 59 −45°
16 — 11 17 38 −54° 10 14 34 −58° 13 20 47 −50° 13 20 53 −51°
18 — 11 17 40 −57° 11 17 44 −58°
H 175 200 225 250 300 350 400
8 15 28 90 −22° 16 30 93 −20° 14 27 86 −24° 16 29 93 −21° 15 28 94 −24° 17 31 105 −20° 18 34 113 −17°
10 17 29 87 −27° 17 31 91 −25° 15 27 82 −30° 17 30 90 −26° 16 28 89 −29° 18 32 103 −25° 20 35 110 −21°
12 18 29 84 −32° 18 31 88 −30° 16 27 78 −35° 18 30 87 −31° 17 28 85 −34° 19 32 98 −30° 21 36 108 −25°
14 18 28 79 −37° 19 30 84 −34° 16 26 73 −41° 18 30 83 −36° 17 27 80 −40° 20 32 95 −34° 23 35 105 −29°
16 18 27 74 −42° 19 29 79 −39° 16 24 67 −47° 19 28 78 −41° 17 25 74 −45° 21 31 90 −38° 23 35 101 −33°
18 17 26 68 −48° 19 28 74 −44° 14 22 60 −53° 18 27 72 −46° 16 24 66 −51° 20 30 85 −43° 23 35 97 −37°
*Distance in feet (see Figure 1).
Table 3. Heater Throw Distances with Standard Horizontal Louvers at Mounting Heights
of 1.5 to 5.5 Meters
Distance*
Louver
Angle
Distance*
Louver
Angle
Distance*
Louver
Angle
Distance*
Louver
Angle
Distance*
Louver
Angle
Distance*
Louver
Angle
H
X Y Z X Y Z X Y Z X Y Z X Y Z X Y Z
Unit Size
030 045 060 075 100 125
1.5 1.8 4.3 9.1 −21° 2.1 4.9 12.2 −20° 2.4 5.5 13.8 −16° 2.7 6.1 17.4 −14° 2.7 6.1 18.0 −18° 3.0 6.7 19.9 −14°
2.4 2.1 4.0 7.9 −39° 2.7 4.9 11.3 −34° 3.0 5.5 12.8 −29° 3.7 6.7 16.5 −25° 3.4 6.4 17.1 −28° 3.7 7.0 19.2 −24°
3.0 1.8 3.4 6.7 −52° 2.7 4.6 10.0 −43° 3.0 5.2 11.9 −37° 3.7 6.7 15.8 −32° 3.7 6.1 15.8 −36° 4.0 7.3 18.3 −30°
3.7 — 2.4 3.7 8.2 −55° 3.0 4.9 10.4 −46° 3.7 6.4 14.6 −39° 3.4 5.8 14.3 −44° 4.3 7.0 17.4 −36°
4.3 — 2.7 4.3 8.8 −56° 3.7 5.8 13.4 −46° 3.4 5.2 12.8 −51° 4.3 6.7 16.1 −43°
4.9 — 3.4 5.2 11.6 −54° 3.0 4.3 10.4 −58° 4.0 6.1 14.3 −50°
5.5 — 3.4 5.2 12.2 −57°
H 150 175 200 225 250 300
2.4 4.0 7.3 22.3 −26° 4.6 8.5 27.4 −22° 4.9 9.1 28.0 −20° 4.3 8.2 26.2 −24° 4.9 8.8 28.3 −21° 4.6 8.5 28.7 −24°
3.0 4.3 7.3 21.0 −32° 5.2 8.8 26.6 −27° 5.2 9.4 27.7 −25° 4.6 8.2 25.0 −30° 5.2 9.1 27.4 −26° 4.9 8.5 27.1 −29°
3.7 4.3 7.3 19.5 −39° 5.5 8.8 25.6 −32° 5.5 9.4 26.8 −30° 4.9 8.2 23.8 −35° 5.5 9.1 26.5 −31° 5.2 8.5 25.9 −34°
4.3 4.3 6.7 18.0 −45° 5.5 8.5 24.1 −37° 5.8 9.1 25.6 −34° 4.9 7.9 22.3 −41° 5.5 9.1 25.3 −36° 5.2 8.2 24.4 −40°
4.9 4.0 6.1 16.2 −51° 5.5 8.2 22.6 −42° 5.8 8.8 24.1 −39° 4.9 7.3 20.4 −47° 5.8 8.5 23.8 −41° 5.2 7.6 22.6 −45°
5.5 3.4 5.2 13.4 −58° 5.2 7.9 20.7 −48° 5.8 8.5 22.6 −44° 4.3 6.7 18.3 −53° 5.5 8.2 21.9 −46° 4.9 7.3 20.1 −51°
Distance*Louver Angle Distance*Louver Angle
H
X Y Z X Y Z
Unit Size
350 400
2.4 5.2 9.4 32.0 −20° 5.5 11.3 34.4 −17°
3.0 5.5 9.8 31.4 −25° 6.1 10.7 33.5 −21°
3.7 5.8 9.8 29.9 −30° 6.4 11.0 32.9 −25°
4.3 6.1 9.8 29.0 −34° 7.0 10.7 32.0 −29°
4.9 6.4 9.4 27.4 −38° 7.0 10.7 30.8 −33°
5.5 6.1 9.1 25.9 −43° 7.0 10.7 26.9 −37°
*Distance in meters (see Figure 1).

7
UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
Mounting Height Requirements
⚠ WARNING ⚠
If touched, the vent pipe and internal heater surfaces that are accessible from outside the heater
will cause burns. Suspend the heater a minimum of 5 feet (1.5 meters) above the floor.
•For best results, the heater should be mounted with certain rules in mind. In general, a unit should be located 8 to
12 feet (2.4 to 3.7 meters) above the floor. Units should always be arranged to blow toward or along exposed wall
surfaces, if possible. Where two or more units are installed in the same room, a general scheme of air circulation
should be maintained for best results.
•Suspended heaters are most effective when located as close to the working zone as possible, and this fact should
be kept in mind when determining the mounting heights to be used. However, care should be exercised to avoid
directing the discharged air directly on the room occupants.
•Partitions, columns, counters, or other obstructions should be taken into consideration when locating the unit heater
so that a minimum quantity of airflow will be deflected by such obstacles.
•When units are located in the center of the space to be heated, the air should be discharged toward the exposed
walls. In large areas, units should be located to discharge air along exposed walls with extra units provided to
discharge air in toward the center of the area.
•At those points where infiltration of cold air is excessive, such as at entrance doors and shipping doors, it is
desirable to locate the unit so that it will discharge directly toward the source of cold air from a distance of 15 to
20 feet (4.6 to 6.1 meters).
•For a location where dirt, dust, or other airborne contaminants are present in the indoor environment, a separated-
combustion unit that uses outside air for combustion is recommended. Using a separated-combustion unit reduces
the buildup of contaminants on the burner. Any buildup on the burner adversely affects the combustion process.
Hazards of Chlorine
The presence of chlorine vapors in the combustion air of gas-fired heating equipment presents a potential corrosion
hazard for separated-combustion heaters with regard to the combustion air inlet. Chlorine is usually found in the form
of freon or degreaser vapors. When chlorine is exposed to flame, it will precipitate from the compound and go into
solution with any condensation that is present in the heat exchanger or associated parts. The result is hydrochloric
acid, which readily attacks all metals including 300 grade stainless steel. Care should be taken to separate these
vapors from the combustion process. This may be done by wise location of the unit vent and combustion air terminals
with regard to exhausters or prevailing wind directions. Chlorine is heavier than air. Keep these facts in mind when
determining installation location of the heater in relation to building exhaust systems.
Dimensions
Unit dimensions are shown in Figure 2 and Figure 3 and listed in Table 4 and Table 5.

8UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
GENERAL INFORMATION—CONTINUED
Dimensions—Continued
Figure 2. Dimensions—Models UBX and UBZ (Refer to Table 4)
A
B
D
C
2 1/2
FRONT
VIEW
HANGER BAR
L
K**
G
J
H**
TOP
VIEW
3/8” - 16 FEMALE
THREAD - FOUR
SUSPENSION POINTS
IN HANGER BARS
T (HANGER BAR LENGTH)
F
RIGHT SIDE VIEW
(ACCESS PANEL)
DIRECT DRIVE
BLOWER ATTACHED
TO THE CABINET
- SIZES 30-75
Q
R
S
P
N
M
THERMOSTAT
CONNECTION
COMBUSTION
AIR INLET
VENT CONNECTION
REAR
VIEW
1/2” NPT EXTERNAL
GAS CONNECTION
DIRECT DRIVE
BLOWER WITH
BLOWER BACK
ON THE CABINET
-SIZES 100-125
E*
BELT DRIVE BLOWER
WITH BLOWER BACK
ON THE CABINET
- SIZES 150-400
NOTES:
1. * SIZES 150-400 - DIMENSION E VARIES WITH MOTOR SELECTION AND BELT ADJUSTMENT.
2. ** DIMENSIONS H AND K ARE THE HEATER SUSPENSION POINTS.

9
UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
Figure 3. Dimensions—Models UDX and UDZ (Refer to Table 5)
A
B
D
C
FRONT
VIEW
E
F
RIGHT SIDE VIEW
(ACCESS PANEL)
Q
N
M
R
P
3/8-16 FEMALE THREAD
- ALL SUSPENSION POINTS
M AND N - HANGER DIMENSIONS
FOR BOTH 2-PT AND 4-PT SUSPENSION
TOP
VIEW
J
G
K
H
S
T
THERMOSTAT
CONNECTION
LINE VOLTAGE INLET
(CONNECTS AT CIRCUIT BOARD)
VENT COLLAR
EXTERNAL GAS CONNECTION
COMBUSTION
AIR INLET
REAR
VIEW
R - HANGER DIMENSION
FOR 2-PT SUSPENSION
P AND Q -
HANGER
DIMENSION
S
FOR 4-PT
SUSPENSION
(4-PT IS
REQUIRED IF
INSTALLING
OPTIONAL
NOZZLE.)
Table 4. Dimensions—Models UBX and UBZ
Unit
Size
Dimension (See Figure 2)
A B C D E*F G H** JK** L M N P Q R S T
Inches (±1/16) (mm (±2))
030,
045
27
(686)
13-3/4
(349)
13-13/16
(351)
10
(254)
17-3/16
(437)
40-3/32
(1018)
25-17/32
(649)
17-3/8
(441)
1-9/16
(40)
22-1/2
(572)
6-15/32
(164)
10
(254)
6
(152)
3-1/2
(89)
2-21/32
(74)
5-31/32
(152)
3-5/16
(84)
31
(787)
060 27
(686)
16-3/4
(425)
13-13/16
(351)
13
(330)
18-11/16
(475)
40-3/32
(1018)
25-17/32
(649)
17-3/8
(441)
1-9/16
(40)
22-1/2
(572)
6-15/32
(164)
12-11/16
(322)
8-11/16
(221)
6-5/16
(160)
2-21/32
(74)
3-5/16
(84)
5-29/32
(150)
31
(787)
075 27
(686)
16-3/4
(425)
13-13/16
(351)
13
(330)
18-11/16
(475)
40-3/32
(1018)
25-17/32
(649)
17-3/8
(441)
1-9/16
(40)
22-1/2
(572)
5-15/32
(139)
12-11/16
(322)
8-11/16
(221)
6-5/16
(160)
2-21/32
(74)
3-5/16
(84)
5-29/32
(150)
31
(787)
100 27
(686)
24-3/4
(629)
13-13/16
(351)
21
(533)
24-1/16
(611)
48-1/8
(1222)
25-17/32
(649)
17-3/8
(441)
1-9/16
(40)
22-1/2
(572)
8-15/32
(215)
19-5/16
(491)
15-5/16
(389)
9-9/16
(243)
2-21/32
(74)
3-5/16
(84)
5-29/32
(150)
31
(787)
125 27
(686)
24-3/4
(629)
13-13/16
(351)
21
(533)
24-1/16
(611)
47-5/8
(1210)
25-17/32
(649)
17-3/8
(441)
1-9/16
(40)
22-1/2
(572)
7-15/32
(190)
19-5/16
(491)
15-5/16
(389)
9-9/16
(243)
2-21/32
(74)
3-5/16
(84)
5-29/32
(150)
31
(787)
150,
175
38-3/16
(970)
20-1/8
(511)
23
(584)
16
(406)
30-31/32
(786)
64-3/4
(1645)
40
(1016)
25-11/16
(653)
1-13/32
(36)
24-1/2
(622)
3-29/32
(99)
13-1/2
(343)
8-1/2
(216)
5-7/16
(138)
4-3/16
(106)
6-1/2
(165)
8-3/16
(208)
42
(1067)
200 38-3/16
(970)
20-1/8
(511)
23
(584)
16
(406)
30-31/32
(786)
64-3/4
(1645)
40
(1016)
25-11/16
(653)
1-13/32
(36)
24-1/2
(622)
3-29/32
(99)
14-9/16
(370)
9-9/16
(243)
5-7/16
(138)
4-3/16
(106)
6-1/2
(165)
8-3/16
(208)
42
(1067)
225,
250
38-3/16
(970)
26-1/8
(664)
23
(584)
22
(559)
37-1/32
(941)
68-1/8
(1730)
40
(1016)
25-11/16
(653)
1-13/32
(36)
24-1/2
(622)
5-29/32
(150)
18-1/16
(459)
13-1/16
(332)
9
(229)
4-3/16
(106)
6-1/2
(165)
8-3/16
(208)
42
(1067)
300,
350,
400
41
(1041)
34-1/8
(867)
23
(584)
30
(762)
41-7/32
(1047)
68-1/8
(1730)
40
(1016)
27-11/16
(703)
1-13/32
(36)
23-1/2
(597)
1-13/32
(36)
22-9/16
(573)
17-1/16
(433)
11-13/16
(300)
4-1/2
(114)
7-5/16
(186)
8-1/2
(216)
42
(1067)
*For unit sizes 150–400, dimension E varies with motor selection and belt adjustment.
**Dimensions H and K are the heater suspension points.

10 UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
Clearances
Units must be installed so that the clearances listed in Table 6 are provided for with regards to combustion air space,
inspection, and service and for proper spacing from combustible construction. Clearance to combustibles is defined
as the minimum distance from the heater to a surface or object for which it is necessary to ensure that a surface
temperature of 90°F (50°C) above the surrounding ambient temperature is not exceeded. Refer to the dimensions
listed in Table 4 and Table 5 and shown in Figure 2 and Figure 3 when determining clearances to combustibles.
Table 5. Dimensions—Models UDX and UDZ
Unit
Size
Dimension (See Figure 3)
A B C D E F G H J K M N P Q R S T
Inches (±1/16) (mm (±2))
030,
045
13-3/4
(349)
27
(686)
10
(254)
13-13/16
(351)
29-3/4
(756)
25-9/16
(649)
6
(152)
5-15/16
(151)
3-1/2
(89)
3-11/32
(85)
17-3/8
(441)
1-9/16
(40)
4-9/32
(109)
13
(330)
9-9/16
(243)
3-3/4
(95)
2-15/16
(75)
060 16-3/4
(425)
27
(686)
13
(330)
13-13/16
(351)
32-23/32
(831)
25-9/16
(649)
8-11/16
(221)
5-15/16
(151)
6
(152)
3-11/32
(85)
17-3/8
(441)
1-9/16
(40)
4-9/32
(109)
13
(330)
9-9/16
(243)
4-1/16
(103)
2-15/16
(75)
075 16-3/4
(425)
27
(686)
13
(330)
13-13/16
(351)
31-29/32
(810)
25-9/16
(649)
8-11/16
(221)
5-15/16
(151)
6
(152)
3-11/32
(85)
17-3/8
(441)
1-9/16
(40)
4-9/32
(109)
13
(330)
9-9/16
(243)
4-1/16
(103)
2-15/16
(75)
100 24-3/4
(629)
27
(686)
21
(533)
13-13/16
(351)
34-9/32
(871)
25-9/16
(649)
15-5/16
(389)
5-15/16
(151)
8-29/32
(226)
3-11/32
(85)
17-3/8
(441)
1-9/16
(40)
4-9/32
(109)
13
(330)
9-9/16
(243)
5-15/32
(139)
2-15/16
(75)
125 24-3/4
(629)
27
(686)
21
(533)
13-13/16
(351)
34-9/32
(871)
25-9/16
(649)
15-5/16
(389)
5-15/16
(151)
8-29/32
(226)
3-11/32
(85)
17-3/8
(441)
1-9/16
(40)
4-9/32
(109)
13
(330)
9-9/16
(243)
5-15/32
(139)
2-15/16
(75)
150,
175,
200
20-1/8
(511)
38-3/16
(970)
16
(406)
23
(584)
48-7/16
(1230)
40
(1016)
9-5/8
(244)
8-5/16
(211)
5-3/8
(137)
6-1/2
(165)
25-11/16
(652)
1-13/32
(36)
8-1/8
(206)
22-3/16
(564)
16-3/8
(416)
5-1/2
(140)
4-1/4
(108)
225,
250
26-1/8
(664)
38-3/16
(970)
22
(559)
23
(584)
48-7/16
(1230)
40
(1016)
13-1/16
(332)
8-5/16
(211)
9
(229)
6-1/2
(165)
25-11/16
(652)
1-13/32
(36)
8-1/8
(206)
22-3/16
(564)
16-3/8
(416)
8-1/16
(205)
4-5/16
(110)
300,
350,
400
34-1/8
(867)
41
(1041)
30
(762)
23
(584)
48-29/32
(1243)
40
(1016)
17-1/16
(433)
8-1/2
(216)
11-
13/16
(300)
7-5/16
(186)
27-11/16
(703)
1-13/32
(36)
8-1/8
(206)
22-3/16
(564)
16-1/4
(413)
11-9/16
(294)
4-1/2
(114)
GENERAL INFORMATION—CONTINUED
Dimensions—Continued
Table 6. Clearances to Combustibles
Heater
Surface
Unit Size
030–125 150–400
Minimum Clearance (Inches (mm))
Top 1 (25) 4 (102)
Flue connector 6 (152) 6 (152)
Access panel 18 (457) 18 (457)
Non-access side 1 (25) 2 (51)
Bottom*1 (25) 1 (25)
Rear** 18 (457) 18 (457)
*Suspend the heater so that the bottom is a minimum of 5 feet (1.5 meters) above the floor.
**Measure rear clearance from the fan motor.
Weights
⚠ WARNING ⚠
Check the supporting structure to be used to verify that it has sufficient load carrying capacity to
support the weight of the unit. Suspend the heater only from the threaded nut retainers or with a
manufacturer-provided kit. Do NOT suspend from the heater cabinet.
NOTE: For unit shipping weight, contact an authorized Factory Distributor.
Before suspending the heater, ensure that the supporting structure to be used has sufficient load-carrying capacity
to support the weight (refer to Table 7) of the unit.

11
UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
Table 7. Unit Weights
Model
Unit Size
030 045 060 075 100 125 150 175 200 225 250 300 350 400
Pounds (kg)
UBX 84
(38)
89
(40)
102
(46)
108
(49)
168
(76)
171
(78)
300
(136)
320
(145)
320
(145)
385
(175)
400
(181)
458
(208)
494
(224)
506
(230)
UBZ 85
(39)
90
(41)
103
(47)
109
(49)
169
(77)
172
(78)
301
(137)
321
(146)
321
(146)
386
(175)
401
(182)
459
(208)
495
(225)
507
(230)
UDX 57
(26)
62
(28)
71
(32)
76
(34)
101
(46)
106
(48)
178
(81)
193
(88)
193
(88)
211
(96)
223
(101)
277
(126)
303
(137)
316
(143)
UDZ 58
(26)
63
(29)
71
(32)
77
(35)
102
(46)
107
(49)
179
(81)
194
(88)
194
(88)
212
(96)
224
(102)
278
(126)
304
(138)
317
(144)
Combustion Air Requirements
⚠ WARNING ⚠
• Do not install a unit in a confined space without providing wall openings leading to and from
the space.
• Unit heater models UBX and UDX are designed to take combustion air from the space in which
the unit is installed and are not designed for connection to outside combustion air intake ducts.
Connecting outside air ducts voids the warranty and could cause hazardous operation.
•For UBZ and UDZ models, refer to the combustion air requirements in the venting instructions listed in Table 1.
•UBX and UDX models must be supplied with the air that enters into the combustion process and is then vented
to the outdoors. Sufficient air must enter the equipment location to replace that which is exhausted through the
heater vent system.
•In the past, the infiltration of outside air assumed in heat loss calculations (one air change per hour) was assumed
to be sufficient. However, current construction methods, which use more insulation, vapor barriers, tighter fitting and
gasketed doors and windows, weather-stripping, and/or mechanical exhaust fans, may now require the introduction
of outside air through wall openings or ducts.
•Under all conditions, enough air must be provided to ensure there will not be a negative pressure condition within
the equipment room or space.
•Requirements for combustion air and ventilation air depend upon whether the unit is located in a confined or
unconfined space. A confined space is defined as a space whose volume is <50 cubic feet per 1,000 BTUh of
the installed appliance input rating. An unconfined space is defined as a space whose volume is ≥50 cubic feet
per 1,000 BTUh of the installed appliance input rating.
•For confined space installation of UBX and UDX models (including those with CV option), provide openings
(depending on the combustion air source) near the floor and ceiling for ventilation and air for combustion, as shown
in Figure 4 and as listed in Table 8.
NOTE: For further details on supplying combustion air to a confined space, refer to the National
Fuel Gas Code ANSI Z223.1a (latest edition).
Figure 4. Confined Space Combustion Air Openings (Refer to Table 8)
CONFINED
SPACE
A
AB
B
C
C

12 UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
Acoustical Considerations
Refer to sound level data listed in Technical Data section when determining unit location based on acoustical
considerations.
Technical Data
Table 9, Table 10, Table 11, and Table 12 list unit technical data.
GENERAL INFORMATION—CONTINUED
Combustion Air Requirements—Continued
Table 8. Determining Confined Space Combustion Air Requirements
Letter*Air Source Required Opening Size Calculate Combustion Air
Requirements
A Air inside building 1 square inch free area per 1000 BTUh Add total BTUh of all appliances in
confined space and divide by figures
at left for square inch free area size of
each (top and bottom) opening
Never <100 square inches free area for each opening
B Outside air through duct 1 square inch free area per 2000 BTUh
C Direct outside air 1 square inch free area per 4000 BTUh
*See Figure 4.
Table 9. Technical Data for UBX and UBZ Models (Unit Sizes 030–125)
Parameter Unit Size
030 045 060 075 100 125
Input heating capacity (BTUh) 30,000 45,000 60,000 75,000 105,000 120,000
Input heating capacity (kW) 8.8 13.2 17.6 22.0 30.8 35.2
Thermal efficiency (%) 82 82 83
Output heating capacity (BTUh)124,600 36,900 49,200 61,500 87,150 99,600
Output heating capacity (kW)17.2 10.8 14.4 18.0 25.6 29.2
Gas connection, natural (inches)21/2 1/2 1/2
Gas connection, propane (inches)21/2 1/2 1/2
Vent connection diameter (inches)3444
Combustion air inlet diameter, UBZ models (inches)3444
Control, 24V (amps) 1.0 1.0 1.0
Full load amps, 115V, UBX models (amps) 3.7 7.1 13.0
Full load amps, 115V, UBZ models (amps) 3.7 7.1 7.3 13.2
Maximum overcurrent protection, 115V (amps)415 15 30
Discharge air temperature rise, minimum/maximum (°F) 45/75 45/75 45/75
Minimum air volume (cfm) 304 456 607 759 1076 1230
Minimum air volume (meters/minute)38.6 12.9 17.2 21.5 30.5 34.8
Maximum air volume (cfm) 506 759 1012 1265 1793 2049
Maximum air volume (meters/minute)314.3 21.5 28.7 35.8 50.8 58.0
Discharge air opening area (feet)20.96 1.25 2.01
Discharge air opening area (meters)20.09 0.12 0.19
Minimum output velocity (fpm) 316 475 486 607 535 612
Minimum output velocity (meters/minute) 96 143 143 179 160 183
Maximum output velocity (fpm) 527 791 810 1012 892 1020
Maximum output velocity (meters/minute) 159 239 239 299 267 305
Standard blower motor size (horsepower) 1/6 1/3 3/4
Blower fan size (inches) 9 × 6 9 × 6 10 × 10
Sound level @ 15 feet (dBa) 40 40 49 54 55
1CSA ratings for elevations up to 2,000 feet.
2Size shown is for gas connection to a single-stage gas valve—not supply line size.
3Smaller and/or larger vent and combustion air pipe diameters may be permissible. Refer to appropriate venting instructions listed in Table 1.
4MOCP = 2.25 × (largest motor FLA) + smallest motor FLA. Answer is rounded to the next lower standard circuit breaker size.

13
UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
Table 10. Technical Data for UBX and UBZ Models (Unit Sizes 150–400)
Parameter Unit Size
150 175 200 225 250 300 350 400
Input heating capacity (BTUh) 150,000 175,000 200,000 225,000 250,000 300,000 350,000 400,000
Input heating capacity (kW) 43.9 51.2 58.6 65.9 73.2 87.8 102.5 117.1
Thermal efficiency (%) 83 83 83 83 82
Output heating capacity (BTUh)1124,500 145,250 166,000 186,750 207,500 249,000 290,500 328,000
Output heating capacity (kW)136.4 42.5 48.6 54.7 60.8 72.9 85.1 96.0
Gas connection, natural (inches)21/2 1/2 3/4 3/4 3/4
Gas connection, propane (inches)21/2 1/2 3/4 3/4 3/4
Vent connection diameter (inches)35 5 5 6 6
Combustion air inlet diameter, UBZ models (inches)36666
Control amps, 24V (amps) 1.0 1.0 1.0 1.0
Full load amps, 115V, UBX models (amps) 5.9 9.6 10.5 12.7 12.7 17.7 27.3
Full load amps, 115V, UBZ models (amps) 5.9 6.3 10.5 12.7 12.7 17.7 27.3
Maximum overcurrent protection, 115V, UBX models (amps)415 20 25 30 30 40 60
Maximum overcurrent protection, 115V, UBZ models (amps)415 25 30 30 40 60
Discharge air temperature rise, minimum/maximum (°F) 45/75 45/75 45/75 45/75 50/80
Minimum air volume (cfm) 1537 1793 2049 2306 2562 3074 3586 4100
Minimum air volume (meters/minute)343.5 50.8 58.0 65.3 72.5 87.0 101.5 116.1
Maximum air volume (cfm) 2562 2989 3416 3843 4270 5123 5977 6185
Maximum air volume (meters/minute)372.5 84.6 96.7 108.8 120.9 145.1 169.2 175.1
Discharge air opening area (feet)22.56 2.56 3.51 3.51 4.79 4.79
Discharge air opening area (meters)20.24 0.24 0.33 0.33 0.45 0.45
Minimum output velocity (fpm) 600 700 800 657 730 642 749 856
Minimum output velocity (meters/minute) 183 213 244 200 223 196 228 261
Maximum output velocity (fpm) 1001 1168 1334 1095 1217 1070 1248 1291
Maximum output velocity (meters/minute) 305 356 407 334 371 326 380 393
Standard blower motor size (horsepower) 1/4 1/2 1/2 3/4 3/4 1-1/2 2
Blower fan size (inches) 12 × 12 12 × 12 15 × 11 15 × 11 15 × 15
Sound level @ 15 feet (dBa) 51 52 53 56 56 59 61 62
1CSA ratings for elevations up to 2,000 feet.
2Size shown is for gas connection to a single-stage gas valve—not supply line size.
3Smaller and/or larger vent and combustion air pipe diameters may be permissible. Refer to appropriate venting instructions listed in Table 1.
4MOCP = 2.25 × (largest motor FLA) + smallest motor FLA. Answer is rounded to the next lower standard circuit breaker size.

14 UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
Table 11. Technical Data for UDX and UDZ Models (Unit Sizes 030–125)
Parameter Unit Size
030 045 060 075 100 125
Input heating capacity (BTUh) 30,000 45,000 60,000 75,000 105,000 120,000
Input heating capacity (kW) 8.8 13.2 17.6 22.0 30.8 35.2
Thermal efficiency (%) 82 83 83 83
Output heating capacity (BTUh)124,600 37,350 49,800 62,250 87,150 99,600
Output heating capacity (kW)17.2 10.9 14.6 18.2 25.5 29.2
Gas connection, natural (inches)21/2 1/2 1/2
Gas connection, propane (inches)21/2 1/2 1/2
Vent connection diameter (inches)3444
Combustion air inlet diameter, UDZ models (inches)3444
Control, 24V (amps) 1.0 1.0 1.0
Full load amps, 115V (amps) 1.9 2.4 2.4 3.7 4.3 5.6
Maximum overcurrent protection, 115V (amps)415 15 15
Normal power consumption, UDX models (watts) 109 155 155 217 276 354
Normal power consumption, UDZ models (watts) 109 155 155 228 292 370
Discharge air temperature rise (°F) 50 55 60 60
Air volume (cfm) 456 629 769 961 1345 1537
Air volume (meters/minute)312.9 17.8 21.8 27.5 36.7 45.9
Discharge air opening area (feet)20.96 1.25 2.01
Discharge air opening area (meters)20.09 0.12 0.19
Output velocity (fpm) 475 656 616 770 668 763
Output velocity (meters/minute) 145 200 188 235 204 233
Open fan motor size (horsepower) 0.02 0.03 0.03 0.06 1/30 1/20
Enclosed fan motor size (horsepower) 0.06 0.06 1/4
Fan motor speed (rpm) 1550 1550 1050
Fan diameter (inches) 10 12 16
Sound level @ 15 feet (dBa) 40 40 49 54 55
1CSA ratings for elevations up to 2,000 feet.
2Size shown is for gas connection to a single-stage gas valve—not supply line size.
3Smaller and/or larger vent and combustion air pipe diameters may be permissible. Refer to appropriate venting instructions listed in Table 1.
4MOCP = 2.25 × (largest motor FLA) + smallest motor FLA. Answer is rounded to the next lower standard circuit breaker size.
GENERAL INFORMATION—CONTINUED
Acoustical Considerations—Continued

15
UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
Table 12. Technical Data for UDX and UDZ Models (Unit Sizes 150–400)
Parameter Unit Size
150 175 200 225 250 300 350 400
Input heating capacity (BTUh) 150,000 175,000 200,000 225,000 250,000 300,000 350,000 400,000
Input heating capacity (kW) 44.0 51.3 58.6 65.9 73.3 87.9 102.6 117.2
Thermal efficiency (%) 83 83 83 83
Output heating capacity (BTUh)1124,500 145,250 166,000 186,750 207,500 249,000 290,500 332,000
Output heating capacity (kW)136.5 42.6 48.7 54.7 60.8 73.0 85.1 97.3
Gas connection, natural (inches)21/2 1/2 3/4 3/4 3/4
Gas connection, propane (inches)21/2 1/2 3/4 3/4 3/4
Vent connection diameter (inches)35 5 5 6 6
Combustion air inlet diameter, UDZ models (inches)36666
Control amps, 24V (amps) 1.0 1.0 1.0 1.0
Full load amps, 115V (amps) 3.8 4.6 7.5 7.5 11.0 11.0
Maximum overcurrent protection, 115V (amps)415 15 15 20 20
Normal power consumption (watts) 392 491 747 747 1086 1086
Discharge air temperature rise (°F) 60 60 60 60
Air volume (cfm) 1921 2242 2562 2882 3202 3843 4483 5123
Air volume (meters/minute)354.4 63.5 72.5 81.6 90.7 108.8 126.9 145.1
Discharge air opening area (feet)22.56 2.56 3.51 3.51 4.79 4.79
Discharge air opening area (meters)20.24 0.24 0.33 0.33 0.45 0.45
Output velocity (fpm) 752 877 1003 820 911 802 936 1069
Output velocity (meters/minute) 229 267 306 250 278 244 285 326
Open fan motor size (horsepower) 1/6 1/6 1/4 1/4 1/2 1/2
Enclosed fan motor size (horsepower) 1/4 1/4 1/4 1/2 1/2
Fan motor speed (rpm) 1050 1050 1050 1050
Fan diameter (inches) 18 18 20 20 24 24
Sound level @ 15 feet (dBa) 51 52 53 56 56 59 61 62
1CSA ratings for elevations up to 2,000 feet.
2Size shown is for gas connection to a single-stage gas valve—not supply line size.
3Smaller and/or larger vent and combustion air pipe diameters may be permissible. Refer to appropriate venting instructions listed in Table 1.
4MOCP = 2.25 × (largest motor FLA) + smallest motor FLA. Answer is rounded to the next lower standard circuit breaker size.

16 UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
INSTALLATION
Unpacking and Inspection
•The unit was test-operated and inspected at the factory prior to crating and was in operating condition.
•It is important to note when uncrating the unit that shipping brackets are attached with cabinet screws. When
removing shipping brackets, re-insert ALL screws into the cabinet.
•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 gas specifications and electrical characteristics of the heater to ensure that they
are compatible with the gas and electric supplies at the installation site.
Read this manual and become familiar with the installation requirements of your particular heater.
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.
Before beginning, make preparations for necessary supplies, tools, and manpower.
Field-removal of heat exchanger tube support—unit sizes 030–125 (optional): in some cases, the heat
exchanger tubes may have shifted during shipment, causing vibration noise against the support during unit
operation. The primary function of the heat exchanger tube support is to support the heat exchanger tubes during
shipment. This support can be removed without affecting the operation of the unit. It is recommended that the
support be removed prior to installing the unit as follows:
a. Remove discharge air louvers, taking care not to lose springs.
b. Remove and discard two screws that secure heat exchanger support located on top of unit.
c. Remove heat exchanger support through discharge opening and discard support.
Reinstall discharge air louvers.
Check to see if there are any field-installed options (refer to Table 13) that need to be assembled/installed
prior to unit installation. Ensure that all options ordered are at the installation site. Instructions are in this
manual or in the option package (option packages are shipped separately).
Table 13. Field-Installed Options
Name Code Description
Vent/combustion air inlet terminal kit CC2 Vertical roof vent
CC6 Horizontal through-wall vent
Vertical louvers CD1 —
Downturn nozzle
CD2 25- to 65-degree variable air deflection range
CD3 50- to 90-degree variable air deflection range
CD4 25- to 65-degree variable air deflection range nozzle with vertical louvers
Manual shutoff valve CE1 Natural gas or propane
Stepdown transformer
CG1 208V/115V
CG2 230V/115V
CG4 460V/115V
Hanger kit
CK8 Adapts 3/8-inch hangers for two-point suspension from 1-inch threaded pipe
CK10 Adapts 3/8-inch hangers for four-point suspension from 1-inch threaded pipe
CK22 Angle brackets for low ceiling mounting (does not include hanger rods)
High-elevation conversion kit DJ20 For installations at elevations >6000 feet

17
UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
Heater Suspension
⚠ WARNING ⚠
• Before suspending the heater, check the supporting structure to be used to verify that it has
sufficient load-carrying capacity to support the weight (refer to Weights section) of the unit.
• The heater must be level for proper operation. DO NOT place or add additional weight to a
suspended heater.
⚠ CAUTION ⚠
• Before lifting the heater, verify that any screws used for holding shipping brackets were re-
installed in the cabinet.
• Before lifting heater model UBZ or UDZ, any unused suspension points on the control side of
the heater MUST be plugged.
• When the heater is lifted for suspension, support the bottom of the heater with plywood or other
appropriately placed material. If the bottom is not supported, damage could occur.
•The heater is designed to be suspended using four-point suspension. A 3/8-16 threaded nut retainer is located at
each suspension point. The heater may be suspended using either 3/8-inch threaded rods or a hanger kit option
package.
•On heater models UBX and UDX, shipped-separate option packages—that should be installed before the heater
is suspended—include vertical louvers, high-elevation kit, multiple heater control, sensor for DDC control, and/
or stepdown transformer. Installation instructions for these option packages are included in the option package.
•In the literature bag shipped with the heater, there are three capscrews (PN 203311) and sealing washers (PN
61658). On UBZ and UDZ models, these capscrews and washers must be used to seal any unused holes in the
top of the heater (control side) after attaching the hanging hardware (see Figure 5).
Figure 5. Plugging Unused Suspension Points (Models UBZ and UDZ Only)
PLUG ANY UNUSED SUSPENSION POINT(S)

18 UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
Figure 6. Option CK10 Hanger Kit
Suspension of Heater Using Option CK22 Hanger Kit
The ceiling suspension kit (option CK22, see Figure 7) allows the heater to be installed 1 inch from the ceiling without
hanger rods. The ceiling suspension kit is used only on unit sizes 030–125 for UDX and UDZ models. Refer to the
installation instructions provided with the kit.
INSTALLATION—CONTINUED
Heater Suspension—Continued
Suspension of Heater with Downturn Nozzle
Downturn nozzle kits (option CD2, CD3, CD4, or CD5) require four-point suspension. Follow the instructions provided
with the kit for downturn nozzle installation.
Suspension of Heater Using CK10 Hanger Kit
Option CK10 (four-point suspension) is for suspending the heater using swivel connectors connected to 1-inch pipe.
Attach the swivel connectors at the 3/8-16 threaded nut retainers. Ensure that the swivel connectors are locked to
the heater as shown in Figure 6.
Figure 7. Option CK22 Hanger Kit

19
UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
Heater Suspension Using Field-Supplied Threaded Rods
The heater may be suspended from 3/8-inch threaded rods using four-point suspension. The recommended maximum
rod length is 6 feet (1.8 meters). The length of the threaded rod extending into the heater MUST NOT exceed 1/2
inch (13 mm). Ensure that the threaded rods are locked to the heater as shown in Figure 8.
Figure 8. Heater Suspension Using Field-Supplied Threaded Rods
Piping Connections
Gas Supply Pressure
The unit is equipped for a maximum gas supply pressure of 1/2 psi, 3.5 kPa, or 14 IN WC.
NOTES:
Supply pressure higher than 1/2 psi requires the installation of an additional service regulator
external to the unit.
PRESSURE TESTING SUPPLY PIPING
• Test pressures above 1/2 psi—disconnect the heater and manual valve from the gas supply line
to be tested. Cap or plug the supply line.
• Test pressures below 1/2 psi—before testing, close the manual valve on the heater.
Gas Supply Piping
⚠ DANGER ⚠
• All components of a gas supply system must be leak tested prior to placing equipment in service.
NEVER TEST FOR LEAKS WITH AN OPEN FLAME. Failure to comply could result in personal
injury, property damage, or death.
• Pipe joint compounds (pipe dope) shall be resistant to the action of liquefied petroleum gas or
any other chemical constituents of the gas being supplied.
•All piping must be in accordance with requirements outlined in the National Fuel Gas Code ANSI/Z223.1 (latest
edition) or CSA-B149.1 and B149.2 (refer to Unit Location section).
•Gas supply piping installation shall conform with good practice and with local codes.
•Support gas piping with pipe hangers, metal strapping, or other suitable material. Do not rely on the heater to
support the gas pipe.
•The heater is orificed for operation with natural gas having a heating value of 1,050 (±50) BTU per cubic foot or
with propane gas having a heating value of 2,550 (±100) BTU per cubic foot. Sizing of gas supply lines depends
on piping capacity and is based on cubic feet per hour based on a 0.3 IN WC pressure drop, a 0.6 specific gravity
for natural gas at 1,050 BTU per cubic feet, and a 1.6 specific gravity for propane at 2,550 BTU per cubic feet. If
the gas at the installation does not meet this specification, consult the factory for proper orificing.
•Variables for sizing gas supply lines are listed in Table 14. When sizing supply lines, consider possibilities of future
expansion and increased requirements. Refer to National Fuel Gas Code for additional information on line sizing.
ADD 3/8-INCH
NUT AND
WASHER TO
LOCK ROD
TO HEATER
3/8-INCH
THREADED ROD

INSTALLATION—CONTINUED
Piping Connections—Continued
Gas Supply Piping—Continued
Table 14. Gas Supply Line Sizes
Length
of Pipe
(Feet)
Diameter of Pipe (Inches)
1/2 3/4 1 1-1/4 1-1/2 2
Natural
Gas Propane Natural Gas Propane Natural Gas Propane Natural Gas Propane Natural Gas Propane Natural Gas Propane
Cubic Feet per Hour
20 92 56 190 116 350 214 730 445 1100 671 2100 1281
30 73 45 152 93 285 174 590 360 890 543 1650 1007
40 63 38 130 79 245 149 500 305 760 464 1450 885
50 56 34 115 70 215 131 440 268 670 409 1270 775
60 50 31 105 64 195 119 400 244 610 372 1105 674
70 46 28 96 59 180 110 370 226 560 342 1050 641
80 43 26 90 55 170 104 350 214 530 323 990 604
90 40 24 84 51 160 98 320 195 490 299 930 567
100 38 23 79 48 150 92 305 186 460 281 870 531
125 34 21 72 44 130 79 275 168 410 250 780 476
150 31 19 64 39 120 73 250 153 380 232 710 433
175 28 17 59 36 110 67 225 137 350 214 650 397
200 26 16 55 34 100 61 210 128 320 195 610 372
20 UBX-UBZ-UDX-UDZ-IOM (03-22) 1034344-C
Supply Piping Connections
•Install a ground joint union and manual shutoff valve upstream of the unit control system, as shown in Figure 9.
•The 1/8-inch plugged tapping in the manual shutoff valve in Figure 9 provides connection for a supply line pressure
test gauge.
•The National Fuel Gas Code requires the installation of a trap with a minimum 3-inch drip leg (see Figure 9). Local
codes may require a drip leg longer than 3 inches (typically 6 inches). To permit burner removal, this drip leg must
extend beyond the edge of the heater.
•Leak-test all connections by brushing on a leak-detecting solution. Bleed trapped air from gas lines as needed.
•The gas connection is made at the pipe nipple that extends outside the cabinet, as shown in Figure 9. Gas
connection sizes are listed in Table 15.
Figure 9. Gas Connections