Reznor UDXC - Supply Piping Connections; General Requirements for Vent Connections

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UBXC-UDXC-IOM (02-24) 1042980-0
Supply Piping Connections
• Install a ground joint union and manual shutoff valve upstream of the unit control system, as shown in Figure 7.
• The 1/8-inch plugged tapping in the manual shutoff valve in Figure 7 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 7). 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 7. Gas
connection sizes are listed in Table 9.
Figure 7. Gas Connections
Table 9. Gas Connection Sizes
Unit Size (MBTUh)
Natural Gas Propane
Connection (Inches)*
30–200 1/2 1/2
225–400 3/4 3/4
*Connection size for a standard unit (not gas supply line size).
General Requirements for Vent Connections
Vent system methods vary depending on whether the installation is residential or commercial/industrial, whether
the vent is dedicated or common, and whether the unit is standard or separated-combustion. Select and follow the
venting instructions that apply to the installation only. For venting separated-combustion units, follow these general
requirements as well as the separated-combustion conversion instructions provided with the kit.
⚠ CAUTION ⚠
• When an existing appliance is removed or replaced in a venting system, verify that the venting
system is properly sized to vent the new appliance. An improperly sized venting system may
result in the formation of condensate, leakage, and/or spillage.
• Do not intermix different vent system parts from different manufacturers in the same venting
system.
NOTE: Venting must be in accordance with local codes and with the National Fuel Gas Code (ANSI
Z223.1) or the Installation Code for Gas Burning Appliances and Equipment (CSA B149.1). Local
requirements supersede national requirements.