Lennox International Inc. TUA75S 用户手册

 

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A-General Recommendations and Requirements 
NOTE - The vent is a passageway, vertical or nearly so, 
used to convey flue gases from an appliance, or its vent 
connector, to the outside atmosphere. The vent 
connector is the pipe or duct that connects a fuel-gas 
burning appliance to a vent or chimney. The combustion 
air inlet is a pipe that connects the appliance to the 
outside atmosphere to convey oxygen from the air to 
the appliance burner. 
Unit heaters must be vented in compliance with all local 
codes or requirements of the local utility, the current 
standards of the (American) National Fuel Gas Code, 
ANSI Z223.1 or (Canada) CSA-B149 Installation Codes, 
and the following instructions. 
A vent connection flange and a combustion air pipe 
connection flange are attached to the back of the unit. 
Single wall vent material shall have all seams and joints 
sealed with pressure sensitive aluminum tape or 
silicone rubber sealant. Aluminum tape must meet the 
provisions of SMACNA AFTS-100-73 Standards. The 
aluminum tape has a temperature rating of 400°F 
(204°C). Silicone rubber sealant must have a 
temperature rating of 482°F (250°C), i.e., Dow Corning 
RTV-736 or equivalent. All joints shall be secured with 
at least two corrosion resistant screws. All joints must 
be checked for gas tightness after installation. 
Single wall vent shall not pass through any attic, interior 
wall, concealed space, or floor. 

 

These separated combustion unit heaters are listed as 
Category I appliances for vertical vent installations. 
 1-These unit heaters are to be vented with NFPA- or 

ANSI- approved chimneys, U.L. listed type B-1 gas 
vents, single wall metal pipe, or listed chimney lining 
system for gas venting where applicable, as well as 
the modifications and limitations listed in figure 2. 
Seal single wall vent material according to the 
section 

Requirements.  Air inlet pipe may be single wall 
metal pipe or U.L. listed single wall metal flex 
connector. A concentric vent/adapter/cap kit as 
specified in these instructions may be used for 
vertical termination. Refer to table 3. 

 2-  The vent connector shall be 3" (76mm) diameter on 

45 units, 4" (100mm) diameter on 60/75 units, and 
5” (127mm) on 100/125 units. The air inlet pipe shall 

be 3” (76mm) diameter on 45 units and 4” (100mm) 
diameter on 60/75/100/125 units. 

3-  Keep the vent and air inlet runs as short as possible 

with a minimum number of elbows. Refer to the 
(American) National Fuel Gas Code ANSI Z223.1 or 
(Canada) CSA-B149 Installation Code for maximum 
vent and vent connector lengths. Horizontal run of 
the vent connector from the induced draft blower to 
the chimney/vent cannot exceed the values in table 
2. Single wall vent connector shall not be insulated. 

4-  If a single wall vent is used in an unheated area it 

shall be insulated with a minimum of 1/2" thick foil 
faced fiberglass 1-1/2# density insulation. Failure to 
do so will result in condensation of flue gases.  

5-  The unit may be vented vertically as a single 

appliance or as a common vent with other gas-fired 
appliances. In common venting situations, vent 
connectors for other appliances must maintain a 4" 
(100mm) vertical separation between the vent 
connectors. Refer to common venting tables in the 
(American) National Fuel Gas Code ANSI Z223.1 or 
(Canada) CSA-B149 Installation Code for proper 
vent size. 

6-  Clearance to combustible material is 6" (152mm) for 

single wall vent material except where a listed 
clearance thimble is used. Clearance to combustible 
material for type B-1 vent or factory-built chimney is 
per manufacturer’s instructions. Clearance to 
combustible material is 1” on vertical sections of the 
concentric vent/adapter/cap kit. 

7-  The vent connector shall be supported without any 

dips or sags. Vertical vents shall be supported in 
accordance with their listing and manufacturers’ 
instructions. All horizontal vent connector runs shall 
have a slope up to the vertical vent of at least 1/4" 
per foot (1mm per 50mm). 

8-  All vertical type B-1 vents, single wall vents, or listed 

chimney lining system must be terminated with a 
listed vent cap or listed roof assembly. 

9-  The vent must extend at least 3' (1m) above the 

highest point where it passes through a roof of a 
building and at least 2’ (0.6m) higher than any part 
of a building within a horizontal distance of 10' 
(3.05m) unless otherwise specified by the 
(American) National Fuel Gas Code, ANSI Z223.1 
or (Canada) CSA-B149 Installation Codes. The vent 
must extend at least 5' (1.6m) above the highest 
connected equipment flue collar.