UDZ Venting Instructions
Table Of Contents
- VENTING INSTRUCTIONS FOR UNIT HEATERS (MODEL UBZ: SEPARATED-COMBUSTION BLOWER TYPE AND MODEL UDZ: SEPARATED-COMBUSTION FAN TYPE)
- GENERAL INFORMATION
- INSTALLATION
- APPENDIX: INSTRUCTIONS FOR ATTACHING DOUBLE-WALL TYPE B VENT PIPE TO SINGLE-WALL PIPE
- FIGURES
- Figure 1. Typical Combustion Air Inlet and Venter Outlet Connections
- Figure 2. Concentric Adapter Box
- Figure 3. Concentric Adapter Box Dimensions (Refer to Table 4)
- Figure 4. Concentric Adapter Box Connections (Refer to Table 4)
- Figure 5. Vent Terminal Options
- Figure 6. Option CC2 Components
- Figure 7. Option CC2 Installation
- Figure 8. Concentric Adapter Box Brackets
- Figure 9. Combustion Air Pipe Installation
- Figure 10. Combustion Air Pipe Through Roof
- Figure 11. Combustion Air Inlet and Vent Terminal
- Figure 12. Option CC6 Components
- Figure 13. Option CC6 Installation
- TABLES
- Table 1. Combustion Air Inlet and Venter Outlet Connection Sizes
- Table 2. Concentric (Outdoor) Pipe Sizes
- Table 3. Diameter and Length of Pipe from Heater to Concentric Adapter Box
- Table 4. Vent Pipe Opening Diameter
- Table 5. Concentric Adapter Box Vent Pipe Sizes
- Table 6. Vertical Vent Terminal/Combustion Air Package (Option CC2) Components
- Table 7. Minimum Spacing Between Center Lines of Vertical Vent Pipes
- Table 8. Horizontal Vent Terminal/Combustion Air Package (Option CC6) Components
- Table 9. Minimum Clearance Requirements for Horizontal Vent Termination Location
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CP-UBZ-UDZ-VENT (02-21) 1034632-0
Condensation Mitigation
• On units with long vent runs—over 50% of maximum vent length allowed—or installed in low ambient conditions
(below 50°F), it is recommended that vent pipes be fitted at the low point of the vent system with a tee, a drip leg,
and a cleanout cap to prevent any moisture in the vent pipe from entering the unit. The drip leg should be inspected
and cleaned out periodically during the heating season.
• Any length of single-wall vent pipe exposed to cold air or run through an unheated area or an area with an ambient
temperature of 50°F or less, must be insulated along its entire length with a minimum of 1/2-inch foil-faced fiberglass,
1-1/2# density insulation.
• On horizontal vent runs, the flue pipe must be pitched down toward the terminal end—1/4-inch per foot for condensate
drainage—for the entire length of the horizontal vent run.
⚠ CAUTION ⚠
• Failure to pitch the vent run properly may damage the heater due to condensate running back
into the unit.
• Exceeding vent pipe diameter and length requirements may result in condensate forming in the
vent pipe.
INSTALLATION
⚠ CAUTION ⚠
Do NOT make actual connections until after reading the instructions and length requirements for
installing the vent/combustion air kit (refer to Vent Terminal Options section).
Concentric Adapter Box Connections
NOTES:
• All UBX and UDZ installations require a concentric adapter box designed to allow both combustion
air and venting with only one building penetration.
• The concentric adapter box is included in the vent/combustion air terminal kit. Components and
instructions depend on whether the vent terminal is horizontal (option CC6) or vertical (option
CC2).
• Horizontal and vertical kits do not use the same adapter box. The only difference is the diameter
of the opening in the box for the vent pipe. On commercial/industrial installations, a vertical vent
requires double-wall pipe and a slightly larger opening through the box.
• Figure 2 shows a typical concentric adapter box and its airflow.
• See Figure 3 for concentric adapter box dimensions.
• When pipe diameters differ, depending on the direction of airflow, join the pipes with either a taper-type reducer
or increaser. Requirements vary depending on the unit size. The connection requirements are the same for both
vertical and horizontal systems, but the length of pipe required varies by installation.
• Figure 4 shows concentric adapter box connections.
• Table 4 lists vent pipe opening diameters shown in Figure 3.
• Table 5 lists connection dimensions shown in Figure 4, DETAIL B.
• Unit sizes 300, 350, and 400 shown in Figure 4, DETAIL C always require a 6- to 5-inch (152- to 127-mm) taper-
type reducer in the vent pipe.