UDBP Venting Requirements

ManualsBrandsReznor ManualsHeating SuppliesPower Vented Gas Fired Unit Heater - 75,000 BTU

Form I-UD&APD Series-V-PV (5-17), P/N 195675R20, Page 10

4.0 Venting

Requirements &

Instructions

Residential or Commercial / Industrial Installation

Vertical Category I, Std Power Vent fan type unit heater

Size 30, 45, 60

On vent systems where at least 75% of the equivalent length of the vent run is

vertical and the vent terminates at least 5 feet above the vent outlet of the heater.

All vertically vented heaters that are Category I must be connected to a chimney or

vent complying with a recognized standard or a lined masonry (or concrete) chimney

with a material acceptable to the authority having jurisdiction. Venting into an unlined

masonry chimney is not permitted.

4.1 Type of Vent

Pipe Required for

Vent Run

Type of Pipe for Standard Vertical (Category I)

Double wall vent pipe - Recommended.

Single wall vent pipe if requirements of the National Fuel Gas Code are followed.

All pipe must be UL listed for Category I appliances.

4.2 Vent Pipe

Diameter and Vent

Length

Vent pipe diameters and maximum vent lengths in TABLE 7 apply to Vertical vents.

Add all straight sections and equivalent lengths for elbows. The total length must

not exceed the Maximum Vent Length. Use only one diameter of vent pipe on an

installation.

Heater

Size

Vent Pipe

Diameter

Maximum Vent

Length

Equivalent

Straight Length

for 90° Elbow

Equivalent

Straight Length

for 45° Elbow

Field-supplied taper type

connection required at the venter

outlet

inches mm feet M feet M feet M

3 76 20 6.1 3 0.9 1.5 0.5

4” to 3” (102mm to 76mm) reducer

4 102 10 3 2 0.6 1 0.3 None

3 76 20 6.1 3 0.9 1.5 0.5

4” to 3” (102mm to 76mm) reducer

4 102 10 3 2 0.6 1 0.3 None

3 76 30 9.1 4 1.2 2 0.6

4” to 3” (102mm to 76mm) reducer

4 102 15 4.6 2 0.6 1 0.3 None

TABLE 7 - Vent Pipe Diameter and Length for Vertical Vents

4.3 Venter (Flue)

Outlet Diameter

Venter Outlet Attachment Requirements:

Depending on the size of vent pipe as determined in Paragraph 4.2 (Vent Pipe

Diameter and Vent Length), attach either the vent pipe directly to the collar or a

taper-type connector. For Category I, attach a 4” appliance adapter from Category I

pipe manufacturer directly to the collar, then use a reducer if using 3” pipe.

4.4 Vent System

Sealing

Vent system joints depend on the type of pipe being used (See, “Type of Vent Pipe

Required for Vent Run”, Paragraph 4.1).

• If using single wall, 26-gauge or heavier galvanized pipe, secure slip-t connections

using sheet metal screws or rivets. Seal all joints and seams of single-wall vent pipe

inside the building with aluminum tape or silicone sealant.

• If using double-wall (Type B) vent pipe, follow the pipe manufacturer’s instructions

or joining pipe sections. For joining double-wall pipe to heater collar, single-wall

pipe and vent cap, follow the illustrated instructions in Addendum Section A.

4.5 Vent System

Support

Support horizontal runs every six feet (1.8M). Support vertical runs of Category I

vent pipe in accordance with the requirements of the pipe manufacturer. Do not rely

on the heater for support of either horizontal or vertical pipes. Use non-combustible

supports on vent pipe.