Trane Gas Unit Heaters Wartungshandbuch

GTND-SVX01B-EN

25 

Observe the following precautions when venting the unit:

1.

Use flue pipe of the same size as the flue connections 
on the gas unit heater:
•

Unit sizes 30–120: Use 4” (120 mm) flue pipe.

Unit sizes 150–400: Refer to 

All heaters must vented with UL Listed Type B vent (or, 
for unit sizes 30–120, single wall vent), a factory built 
chimney, or a lined brick and mortar chimney that has 
been constructed in accordance with the National 
Building Code. 

Unit sizes 30–120: All tables and dimensions assume B 
vent for the flue and single wall pipe or B vent for the 
connector.

2. Unit sizes 30–120: Unit may be common vented when 

installed in accordance with NFPA-54 guidelines.

3. Provide as long a vertical run of flue pipe at the gas unit 

heater as possible. A minimum of 5 feet (1.5 m) of 
vertical flue is required for Category I venting. The top 
of the vent pipe should extend at least 2 feet (0.61 m) 
above the highest point on the roof. Consideration 
should be made for anticipated snow depth.

Unit sizes 150–400: Install an Amerivent Americap or 
Metalbestos vent cap over the vent opening.

4. Slope horizontal runs upward from the gas unit heater 

at least 1/4-inch per foot (21-mm/m) minimum. 
Horizontal Vent Connector length should not exceed 
75% of the vertical height of the vent pipe, or chimney, 
above the flue pipe connection. Maximum vent 
connector length is 10 feet (3 m). For exceptions see 
Ch. 10 of the National Fuel Gas Code, ANSI Z223.1. 
Horizontal portions of the venting system shall be 
supported at maximum intervals of 4 feet (1.2 m): see 

; in Canada, support at 3-foot intervals 

(1-m) minimum intervals. Maintain clearance between 
the vent pipe and combustible materials per vent pipe 
manufacturer’s instructions.

5. Use as few elbows as possible.

6. Seal all vent pipe joints and seams to prevent leakage. 

Use General Electric RTV-108, Dow-Corning RTV-732, 
or equivalent silicone sealant with a temperature 
rating of 500°F, or 3M #425 aluminum foil tape (or 
equivalent). Tape flue pipe joints with high-temp, RTV 
or foil face tape. 

7.

Avoid running vent pipe through unheated spaces. 
When this cannot be avoided, insulate the pipe to 
prevent condensation of moisture on the walls of the 
pipe. Insulate vent pipe runs longer than 10 ft (3 m). 
Insulation should be a minimum of 1/2” (12.7 mm) 
thick foil faced.

8. Do not damper the flue piping. Failure to open such a 

damper prior to operating the gas unit heater will result 
in the spillage of flue gas into the occupied space.

9. Avoid installing units in areas under negative pressure 

due to large exhaust fans or air conditioning. When 
required, a flue vent fan should be installed in 
accordance with the instructions included with the fan.

10. Vent connectors serving Category I and Category II 

heaters shall not be connected into any portion of 
mechanical draft systems operating under positive 
pressure.