MODELS UDBP AND UBX: STANDARD POWER VENT BLOWER TYPE
MODELS UDBS AND UBZ: SEPARATED-COMBUSTION BLOWER TYPE
MODELS UDAP AND UDX: STANDARD POWER VENT FAN TYPE
MODELS UDAS AND UDZ: SEPARATED-COMBUSTION FAN TYPE
GENERAL INFORMATION
These gas conversion kits are for standard power vent or separated-combustion heaters equipped with either a
single-stage or two-stage gas valve.
Model Identification
When converting fuels, it is necessary to have the complete heater model. The identifying model number can be
found on the heater rating plate. The rating plate identifies only original equipment so also compare the label on the
gas valve with the description listed.
⚠ 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.
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.
⚠ DANGER ⚠
• All gas conversion must be done by a qualified service person in accordance with these instructions
and in compliance with all codes and requirements. 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 the CAN/CGA-B149.1 and CAN/CGA-B149.2 installation code.
• The gas burner in this gas-fired equipment is designed 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
which 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.
• On separated combustion heaters, install either the horizontal or vertical combustion air/vent
system illustrated in the heater venting manual, using the concentric adapter supplied. For all
heater installations, always comply with the combustion air requirements in the installation codes
and instructions. Standard Power Vent heaters installed in a confined space must be supplied
with air for combustion 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 or vent/combustion
air system in structurally sound and proper operating condition.
• 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.
• 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.
2
CP-UB-UD-GC (04-21) 1034364-A
CONVERSION KIT SELECTION
Each conversion kit includes two or three spring kits and burner orifices for multiple unit sizes. Some parts will not
be used—carefully select the parts to be used. Refer to Table 1 for a list of natural gas to propane conversion kit
components. Refer to Table 2 for a list of propane to natural gas conversion kit components.
Table 1. Natural Gas to Propane Conversion Kit Components
Unit
Size
030,
045
060,
075
100,
125
150,
175
200,
225,
250
300,
350,
400
*Used only at installation elevations >2000 feet (>610 meters).
**The plate from kit PN 269837 is not used on unit size 125 models. The plate from kit PN 269838 is not used on unit size 175 models for
residential or commercial applications.
Model
(Kit PN)
All
UDBP, UDBS
(269840) or UBX,
UBZ (1036541R)
UDAP, UDAS
(269835) or UDX,
UDZ (1036536R)
UDBP, UDBS
(269841) or UBX,
UBZ (1036542R)
UDAP, UDAS
(269836) or UDX,
UDZ (1036537R)
UDAP, UDAS,
UDBP, UDBS,
(269837) or UBX,
UBZ, UDX, UDZ
(1036538R)
UDAP, UDAS,
UDBP, UDBS,
(269838) or UBX,
UBZ, UDX, UDZ
(1036539R)
UDAP, UDAS,
UDBP, UDBS,
(269839) or UBX,
UBZ, UDX, UDZ
(1036540R)
UDAP, UDAS,
UDBP, UDBS,
(201732) or UBX,
UBZ, UDX, UDZ
(1036543R)
ComponentDescriptionPN
Spring kit#393691 for single-stage valve VR8105, VR8205, or VR830598720
TapeConversion64391
DiskPropane37752
Label*
Spring kit#396221 for single-stage valve VR8215260605
Burner orificesRefer to Table 3
PlateAir restrictor, 1-3/16-inch (30 mm) diameter opening203078
Spring kit#396221 for a VR8215 single-stage valve260605
Burner orificesRefer to Table 3
PlateAir restrictor, 1-3/8-inch (35 mm) diameter opening196687
#396221 for single-stage valve VR8215260605
#396021 for two-stage valve VR8105, VR8205, or VR8305197207
#396221 for a VR8215 single-stage valve260605
#396021 for two-stage valve VR8105, VR8205, or VR8305197207
#396221 for single-stage valve VR8215260605
#396021 for two-stage valve VR8105, VR8205, or VR8305197207
Air restrictor, 1-3/4-inch (44 mm) diameter opening196688
#396221 for single-stage valve VR8215260605
#396021 for two-stage valve VR8105, VR8205, or VR8305197207
Air restrictor, 1-3/4-inch (44 mm) diameter opening196688
#396221 for single-stage valve VR8215260605
#396021 for two-stage valve VR8105, VR8205, or VR8305197207
#393691 for single-stage valve VR8305K987203/4-inch, single-stage
#396021 for two-stage valve VR8105, VR8205, or VR8305197207
Gas Valve
(Manufacturer’s PN)
—
1/2-inch, single-stage
(VR8105K2942,
VR8205K2957, or
VR8215T1239)
1/2-inch, single-stage
(VR8105K2942,
VR8205K2957, or
VR8215T1239)
or
1/2-inch, two-stage
(VR8105N2949 or
VR8205N2921)
1/2-inch, single-stage
(VR8205K2957 or
VR8215T1239)
or
1/2-inch, two-stage
(VR8205N2921)
1/2-inch, single-stage
(VR8205K2957 or
VR8215T1239),
3/4-inch single-stage
(VR8305K4241),
or
1/2-inch, two-stage
(VR8205N2921 or
VR8305N4297)
(VR8305K4241)
or
3/4-inch, two-stage
(VR8305N4297)
CP-UB-UD-GC (04-21) 1034364-A
3
CONVERSION KIT SELECTION—CONTINUED
Table 2. Propane to Natural Gas Conversion Kit Components
Unit
Size
030,
045
060,
075
100,
125
150,
175
200,
225,
250
300,
350,
400
*Used only at installation elevations >2000 feet (>610 meters).
Model
(Kit PN)
All
UDAP, UDAS,
UDBP, UDBS,
(269851) or UBX,
UBZ, UDX, UDZ
(1036544R)
UDAP, UDAS,
UDBP, UDBS,
(269852) or UBX,
UBZ, UDX, UDZ
(1036545R)
UDAP, UDAS,
UDBP, UDBS,
(269853) or UBX,
UBZ, UDX, UDZ
(1036546R)
UDAP, UDAS,
UDBP, UDBS,
(269854) or UBX,
UBZ, UDX, UDZ
(1036547R)
UDAP, UDAS,
UDBP, UDBS,
(269855) or UBX,
UBZ, UDX, UDZ
(1036548R)
UDAP, UDAS,
UDBP, UDBS,
(201738) or UBX,
UBZ, UDX, UDZ
(1036549R)
ComponentDescriptionPN
Spring kit#394588 for single-stage valve VR8105, VR8205, or VR830598721
TapeConversion64391
DiskNatural gas1401
Label**
Spring kitSpring kit #396222 for a VR8215 single-stage valve261651
Burner orificesRefer to Table 3
Spring kit
Burner orificesRefer to Table 3
Spring kit
Burner orificesRefer to Table 3
Spring kit
Burner orificesRefer to Table 3
Spring kit
Burner orificesRefer to Table 3
Spring kit#396205 for two-stage valve VR8105, VR8205, or VR8305197208
Burner orificesRefer to Table 3
High-elevation adjustment197062
#396222 for single-stage valve VR8215261651
#396205 for two-stage valve VR8105, VR8205, or VR8305197208
#396222 for single-stage valve VR8215261651
#396205 for two-stage valve VR8105, VR8205, or VR8305197208
#396222 for single-stage valve VR8215261651
#396205 for two-stage valve VR8105, VR8205, or VR8305197208
#396222 for sinle-stage valve VR8215261651
#396205 for two-stage valve VR8105, VR8205, or VR8305197208
Gas Valve
(Manufacturer’s PN)
—
1/2-inch, single-stage
(VR8105K2959,
VR8205K2965, or
VR8215T5214)
1/2-inch, single-
stage (VR85K2959,
VR8205K2965, or
VR8215T5214)
or
1/2-inch, two-stage
(VR8105N2931 or
VR8205N2913)
1/2-inch, single-
stage (VR85K2959,
VR8205K2965, or
VR8215T5214),
3/4-inch single-stage
(VR8305N4258),
1/2-inch, two-stage
(VR8105N2931 or
VR8205N2913),
or
3/4-inch, two-stage
(VR8305N4289)
3/4-inch, single-stage
(VR8305N4258) or
3/4-inch, two-stage
(VR8305N4289)
INSTALLATION
Install the conversion kit in accordance with the following steps. Ensure that the kit is correct for the size of the heater
being serviced (refer to Table 1 or Table 2). Heater component locations are shown in Figure 1.
1. Remove gas supply and electrical power:
a. Turn off gas supply at shutoff valve outside of heater.
b. Turn off electrical power.
c. Open control access panel.
4
CP-UB-UD-GC (04-21) 1034364-A
(unit sizes 030–125)
Separated Combustion Units
have a collar
here for the
combustion air
pipe (not shown)
Interlock Door
Switch: Separated
Combustion Units
Electric Box:
UDAS and UDBS
models ONLY
Disconnect Switch:
Separated Combustion units ONLY
2. Install regulator spring kit:
DETAIL ADETAIL B
AIR RESTRICTOR PLATE*
BURNER
ORIFICE
TABS NOT BENT
AIR RESTRICTOR
PLATE INSTALLED
(TABS BENT)
VENTURI TUBE
*
USED ONLY ON UNIT SIZES 030, 045, 060, 075, 100, AND 150 (ALL PROPANE MODELS) AND UNIT SIZE
125 (PROPANE MODELS UDBP, UDBS, UBX, AND UBZ).
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: After a new regulator spring kit is installed, it is necessary to adjust the spring for correct
manifold pressure. This adjustment can be made only after the heater is in operation (refer to step 7).
3. Remove or install air restrictor plate as necessary and replace burner orifice:
a. Carefully remove existing burner orifice (see Figure 2, DETAIL A).
Figure 1. Heater Components
⚠ WARNING ⚠
CP-UB-UD-GC (04-21) 1034364-A
Figure 2. Burner Orifice and Air Restrictor Plate
5
INSTALLATION—CONTINUED
⚠ DANGER ⚠
• The air restrictor plate MUST BE INSTALLED when converting unit sizes 030, 045, 060, 075, 100,
and 150 (all models) and unit size 125 (models UDBP, UDBS, UBX, and UBZ) to propane.
• The air restrictor plate MUST BE REMOVED when converting unit sizes 030, 045, 060, 075, 100,
and 150 (all models) and unit size 125 (models UDBP, UDBS, UBX, and UBZ) to natural gas.
• For these models/unit sizes, the failure to install or remove the air restrictor plate in accordance
with the following directions can cause death or injury and/or property damage.
b. For unit sizes 030, 045, 060, 075, 100, and 150 (all models) and unit size 125 (models UDBP, UDBS, UBX,
and UBZ), proceed to step c. For all other models/unit sizes, proceed to step e.
c. If converting from propane to natural gas, remove air restrictor plate as follows. If converting from natural gas
to propane, install air restrictor plate in accordance with step d.
(1) See Figure 2, DETAIL B to locate air restrictor plate held in place on venturi tube by its bent tabs.
(2) Use pliers to carefully unbend tabs as shown in Figure 2, DETAIL A and remove air restrictor plate.
d. For natural gas to propane conversion, install air restrictor plate as follows:
(1) Refer to Table 1 or Table 2 to select correct air restrictor plate. Slide plate in place over venturi tube
opening so that its 45-degree angle is hooked over rear of venturi tube (see Figure 2).
(2) While holding plate in position, use pliers to carefully bend tabs to lock plate in place (see Figure 2, DETAIL
B). Ensure that air restrictor is aligned and secure.
e. For all conversions, select replacement burner orifices in accordance with Table 3. All conversion kits include
two or three burner orifices. Other included orifice(s) will not be used.
Table 3. Burner Orifices
Unit SizeModel
030
045
060
075
100
125
150
175
200
225All6.95 mm (221121)11/64 inch (196901)
250
300
350
400
UDAP, UDAS, UDBP, UDBS#37 (196853)
UBX, UBZ, UDX, UDZ#39 (196852)
UDAP, UDAS, UDBP, UDBS#30 (196838)
UBX, UBZ, UDX, UDZ3.1 mm (120144)
UDAP, UDAS, UDBP, UDBS3.7 mm (196839)2.3 mm (196846)
UBX, UBZ, UDX, UDZ#28 (124969)2.25 mm (1034350)
UDAP, UDAS, UDBP, UDBS#19 (196855)#39 (196852)
UBX, UBZ, UDX, UDZ#22 (196361)#40 (120137)
UDAP, UDAS, UDBP, UDBS#10 (120158)3.0 mm (196854)
UBX, UBZ, UDX, UDZ#14 (208247)#32 (120141)
UDAP, UDAS, UDBP, UDBS#4 (196840)3.2 mm (196847)
UBX, UBZ, UDX, UDZ#10 (120158)3.1 mm (120144)
UDAP, UDAS, UDBP, UDBS5.9 mm (131581)9/64-inch (196898)
UBX, UBZ, UDX, UDZ5.6 mm (208243)3.5 mm (120148)
UDAP, UDAS, UDBP, UDBSE (196891)#24 (196899)
UBX, UBZ, UDX, UDZ6.0 mm (208245)#27 (120149)
UDAP, UDAS, UDBP, UDBS6.8 mm (196892)
UBX, UBZ, UDX, UDZF (120167)
UDAP, UDAS, UDBP, UDBS
UBX, UBZ, UDX, UDZ4.60 mm (1034352)
UDAP, UDAS, UDBP, UDBS8.0 mm (221122)
UBX, UBZ, UDX, UDZ7.8 mm (208253)
UDAP, UDAS, UDBP, UDBS8.7 mm (221123)#3 (196904)
UBX, UBZ, UDX, UDZ8.5 mm (1034354)5.4 mm (1034353)
UDAP, UDAS, UDBP, UDBS9.6 mm (196897)
UBX, UBZ, UDX, UDZ9.2 mm (1034355)
Natural GasPropane
Orifice Size/Marking (PN)
1.6 mm (196844)
#48 (196845)
4.1 mm (196900)
L (208255)
#14 (196902)
#8 (196903)
5.8 mm (196905)
6
CP-UB-UD-GC (04-21) 1034364-A
⚠ WARNING ⚠
Do not attempt to drill burner orifice. Use factory-supplied orifice only.
f. Install replacement burner orifice (see Figure 2, DETAIL A).
⚠ CAUTION ⚠
If the heater will be operated at an elevation >6,000 feet (>1,830 meters), a high-elevation pressure
switch must be installed.
NOTES:
• If the installation elevation is >6,000 feet (>1,830 meters), verify that the elevation on the rating
plate or high-elevation label is >6,000 feet (>1,830 meters). If the rating plate or label does not
indicate an elevation of >6,000 feet (>1,830 meters), order and install the appropriate high pressure
switch kit.
• If the heater is equipped for installation at an elevation of >6,000 feet (>1,830 meters) and is being
installed at a lower elevation, order and install the appropriate switch.
• Contact your distributor to select the factory-authorized replacement part.
4. For installations at elevations >6,000 feet (>1,830 meters), replace pressure switch:
a. Locate pressure switch in control compartment (see Figure 1) and mark and disconnect two pressure switch
wires.
b. Mark and disconnect sensing tube(s) from pressure switch.
c. Remove two screws that secure mounting bracket and remove bracket and pressure switch. Save bracket
and screws for reuse.
d. Install replacement pressure switch using mounting bracket and two screws. Reconnect sensing tube(s) and
wires.
5. Restore electrical power and gas supply:
a. Turn on electrical power.
b. Turn on gas supply and relight heater, following instructions on heater.
6. Perform leak test:
a. Check all connections for gas leaks using commercial leak-detecting fluid or rich soap and water solution.
Leaks are indicated by presence of bubbles.
b. If leak is detected, tighten connection. If leak cannot be stopped by tightening connection, replace part(s).
7. Adjust manifold (outlet) pressure:
⚠ WARNING ⚠
Manifold gas pressure must never exceed 3.5 IN WC for natural gas or 10 IN WC for propane.
a. Determine correct outlet pressure (refer to Table 4) for elevation of installation. If unsure of elevation, contact
local gas supplier.
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 3).
CP-UB-UD-GC (04-21) 1034364-A
7
SINGLE-STAGE VA LVES
TWO-STAGE VA LV 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 TAP
1/8" OUTLET PRESSURE TAP
HIGH-FIRE
REGULATOR SCREW
LOW-FIRE
REGULATOR SCREW
INSTALLATION—CONTINUED
Table 4. Required Manifold (Outlet) Gas Pressure
ElevationSingle-Stage and Two-Stage High-FireTwo-Stage Low-Fire
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. For single-stage or two-stage high fire valve:
(1) Turn knob or switch on top of valve to ON.
(2) Remove cap from regulator screw (see Figure 3) and adjust pressure in accordance with Table 4 by turning
regulator screw IN (clockwise) to increase pressure or OUT (counterclockwise) to decrease pressure.
e. For two-stage low fire valve:
(1) Disconnect wire from HI terminal on gas valve.
(2) Remove cap from low-fire regulator screw (see Figure 3) and adjust pressure in accordance with Table
4 by turning regulator screw IN (clockwise) to increase pressure or OUT (counterclockwise) to decrease
pressure.
(3) Reconnect wire to Hi terminal on gas valve.
f. Turn up thermostat. For models UDAS, UDBS, UBZ, and UDZ, depress and hold door safety switch.
g. Cycle burner once or twice to properly seat adjustment spring in valve and recheck outlet pressure. When
pressure corresponds to Table 4, disconnect manometer and install cap on regulator screw.
h. Check for leakage at 1/8-inch outlet pressure tap fitting. Correct as necessary.
i. Connect manometer to inlet pressure tap (see Figure 3). While heater is operating, measure inlet pressure,
which should be as follows:
(1) between 5 and 13.5 IN WC for all natural gas models
(2) between 10 and 13.5 IN WC for UDAP, UDAS, UDBP, and UDBS propane models
(3) between 11 and 13.5 IN WC for UBX, UBZ, UDX, and UDZ propane models
j. If inlet pressure is not in accordance with step 7i, it must be corrected by adjusting manifold (outlet) pressure
in accordance with steps 7b through 7e.
NOTES:
• Conversion of a unit using these kits does not alter the input rate. Refer to the rating plate on
the heater for the input rate and other appropriate information.
• If adjusted for high-elevation operation, the input rate will be affected.
• The high-elevation adjustment label is not used on units operated at elevations of ≤2,000 feet
(≤610 meters).
k. Refer to APPENDIX for input and capacity values for elevation of installation.
(1) Use permanent marker to fill in appropriate input and capacity values on high-elevation adjustment label
from literature bag provided with unit.
(2) Select location for label on outside of heater access panel that will be conspicuous to anyone operating
or servicing unit.
(3) Ensure that surface is clean and dry and affix label.
l. Observe heater operation for at least one complete cycle to check for safe and proper operation. For models
UDAS, UDBS, UBZ, and UDZ, depress and hold safety door switch.
8. Close control access panel.
CP-UB-UD-GC (04-21) 1034364-A
9
APPENDIX: INPUTS AND CAPACITIES BY ELEVATION
Inputs and Capacities by Elevation in US
Elevation
(Feet (Meters))
0–2000
(0–610)
2001–3000
(611–915)
3001–4000
(916–1220)
4001–5000
(1221–1525)
5001–6000
(1526–1830)
6001–7000
(1831–2135)
7001–8000
(2136–2440)
8001–9000
(2441–2745)
9001–10,000
(2746–3045)
Value*
*A = normal input, B = thermal output capacity, and C = minimum input.