Lennox International Inc. TUA45S 사용자 설명서

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Gas Connection 
 
When connecting gas supply, the length of the run from 
the meter must be considered in determining the pipe 
size. A line pressure of 7" w.c. (1.74 kPa) for natural gas 
should be maintained when sizing piping. A line pressure 
of 13” w.c. (3.23 kPa) should be maintained for liquefied 
petroleum (LP) gas. A minimum of 5.0" w.c. for natural 
gas or 10.4" w.c. for LP/propane gas should be 
maintained for proper unit operation. For correct sizing of 
piping, refer to the (American) National Fuel Gas Code 
ANSI Z223.1 or (Canada) CSA-B149 Installation Code or 
consult the utility having jurisdiction. 
A drip leg should be installed in the vertical pipe run to the 
unit. In some localities, codes may require that a manual 
main shutoff valve and union (furnished by installer) be 
installed external to the unit. Union must be of the ground 
joint type. A drip leg should be readily accessible to permit 
cleaning and emptying. See figure 9. Leave a minimum of 
4" (102mm) clearance between electric box and drip leg. 
A 1/8" NPT plugged tap shall be installed immediately 
upstream of the gas supply connection to the heater. 
NOTE - Compounds used on threaded joints of gas piping 
must be resistant to the actions of liquefied petroleum 
gases. 
 
FIGURE 9 
GROUND
 
JOINT UNION
 
DRIP LEG
 
MANUAL
 
MAIN SHUT-OFF VALVE
(Furnished by Installer)
GAS FLOW
 
1/8 NPT
 
PLUGGED TAP
 
GAS SUPPLY CONNECTION
 
 
Leak Check 
 
After gas piping is completed, carefully check all piping 
connections, (field and factory), for gas leaks. Use a soap 
solution or other preferred means. 
CAUTION - DO NOT use matches, candles, flame or 
other sources of ignition to check for gas leaks. 
IMPORTANT - The heater and its individual shut off valve 
must be disconnected from the gas supply piping system 
during any pressure testing of that system at test 
pressures in excess of 1/2 psig (3.45kPa). 
The appliance must be isolated from the gas supply 
piping system by closing its individual manual gas shutoff 
valve during any pressure testing of the gas supply 
system at test pressures equal to or less than 1/2 psig 
(3.45kPa). See figure 10. 
NOTE - In case emergency shutdown is required, shut 
down main gas valve and disconnect main power to unit. 
These devices should be properly labeled by the installer. 
 
FIGURE 10 
MANUAL MAIN SHUT-OFF
 
VALVE WILL NOT
HOLD NORMAL
TEST PRESSURE
CAP
ISOLATE
GAS VALVE
GAS SUPPLY TO UNIT HEATER
UNIT HEATER