Left Side Supply Gas Pipe Arrangement; Gas Piping - Johnson Controls TM9T Series Installation Manual

1083286-UIM-L-1219
GAS PIPING INSTALLATION
Properly sized wrought iron, approved flexible or steel pipe must be
used when making gas connections to the unit. If local codes allow the
use of a flexible gas appliance connection, always use a new listed con-
nector. Do not use a connector that has previously serviced another gas
appliance.
Some utility companies or local codes require pipe sizes larger than the
minimum sizes listed in these instructions and in the codes. The furnace
rating plate and the instructions in this section specify the type of gas
approved for this furnace - only use those approved gases. The instal-
lation of a drip leg and ground union is required. Refer to Figure 12.
For left side supply gas pipe arrangement, two 1/2" elbows and two 1/2"
x 1-1/2" pipe nipples must be used. The arrangement shown in Figure
11 aligns entrance hole in furnace casing with supply gas pipe. Furnace
casing does not support installations completed using street-elbows.
To Gas
Supply
External
Manual
Shut-off
Valve
Ground
Union
Drip
Leg
Upflow
Configuration
FIGURE 12: Gas Piping
IMPORTANT: An accessible manual shutoff valve must be installed
upstream of the furnace gas controls and within 6 feet (1.8 m) of the
furnace.
The furnace must be isolated from the gas supply piping system by
closing its individual external manual shutoff valve during any pressure
testing of the gas supply piping system at pressures equal to or less
than 0.5 psig (3.5 kPa).
CAUTION
!
The gas valve body is a very thin casting that cannot take any exter-
nal pressure. Never apply a pipe wrench to the body of the gas valve
when installing piping. A wrench must be placed on the octagon hub
located on the gas inlet side of the valve. Placing a wrench to the
body of the gas valve will damage the valve causing improper opera-
tion and/or the valve to leak.
Gas piping may be connected from either side of the furnace using any
of the gas pipe entry knockouts on both sides of the furnace. Refer to
Figures 8 and 12.
10
To Gas
NOTE: Ground Union maybe installed inside or outside unit.
Supply
External
Manual
Shut-off
Ground
Valve
Union
To Gas
Supply
Gas
Valve
Gas
Pipe
Drip
Leg
Ground
Union
Gas
Drip
Pipe
Leg Downflow
Configuration
FIGURE 11: Left Side Supply Gas Pipe Arrangement
To Gas
Supply
Ground
Union
Gas
Valve
Drip
Leg
Horizontal
Configuration
GAS ORIFICE CONVERSION FOR PROPANE (LP)
This furnace is constructed at the factory for natural gas-fired operation,
but may be converted to operate on propane (LP) gas by using a fac-
tory-supplied LP conversion kit. Follow the instructions supplied with
the LP kit.
HIGH ALTITUDE MANIFOLD PRESSURE SETTINGS
This furnace is constructed at the factory for natural gas-fired operation
at 0 – 7,999 feet (0 – 2,438 m) above sea level.
The manifold pressure must be changed in order to maintain proper
and safe operation when the furnace is installed in a location where the
altitude is greater than 7,999 feet (2,438 m) above sea level. Refer to
Tables 4 and 5 for proper manifold pressure settings.
HIGH ALTITUDE PRESSURE SWITCH CONVERSION
For installation where the altitude is less than 5,000 feet (1,524m), it is
not required that the pressure switch be changed unless you are in an
area subject to low pressure inversions.
Ground
To Gas
Union
Supply
Drip Leg
External Manual
Shut-off Valve
Gas
Valve
To Gas
Gas
Supply
Pipe
Ground
Union
Drip
Leg
Johnson Controls Ducted Systems