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Gas piping
Gas safety
WARNING
An overpressure protection device, such as a
pressure regulator, must be installed in the gas piping
system upstream of the furnace and must act to limit
the downstream pressure to the gas valve so it does
not exceed 0.5 psig (14 in. W.C., 3.48 kPa). Pressures
exceeding 0.5 psig (14 in. W.C., 3.48 kPa) at the gas
valve can damage the gas valve and subsequently
the furnace or some of its components, leading to
possible gas-related fire, explosion, property damage,
and loss of life.
Figure 14: Gas valve
Figure 15: Supply gas pipe arrangement
Installation Manual: Z8ES Single-Stage Standard ECM Residential Gas Furnaces (Non-condensing Multi-position Standard
Important: Plan the gas supply routing before
determining the correct gas pipe entry. Use 90°
conventional elbows and short pipe nipples to enter
through the cabinet access holes.
Gas piping installation
You must use correctly sized wrought iron, approved
flexible or steel pipe when making gas connections to the
unit. If local codes allow the use of a flexible gas appliance
connection, always use a new listed connector. 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 installation of a drip leg and ground union is
required. See Figure 15.
Important: You must install an accessible manual
shutoff valve upstream of the furnace gas controls
and within 6 ft (1.8 m) of the furnace.
You must isolate the furnace 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 1/2 psig (3.5
kPa).
Johnson Controls Ducted Systems
17
and Low NOx)
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