4000-SERIES INSTALLATION, OPERATION AND SERVICE MANUAL
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SECTION 18: GAS PIPING
18.1 Gas Manifolds
All gas piping to the air handler must comply with:
United States: Refer to NFPA 54/ANSI Z223.1 - latest
revision, National Fuel Gas Code.
Canada: Refer to CSA B149.1 - latest revision,
Natural Gas and Propane Installation Code.
The air handlers are available with three gas manifold
options.
• American National Standards Institute (ANSI)
compliant manifold: (
See Page 71, Figure 55
).
•Factory Mutual (FM)-compliant manifold:
(
See Page 72, Figure 56
).
•XL Insurance (former IRI)-compliant manifold:
(
See Page 73, Figure 57
).
18.2 Gas Piping and Pressures
The air handler is equipped with a gas manifold
suitable for connection to supply pressure of up to 5
p.s.i. maximum for all manifold types.
When gas supply exceeds the above-listed maximum
gas pressures, an additional high pressure gas
regulator will be required to assure that the correct
gas pressure is supplied to the air handler.
Outlet pressure from the regulator / inlet pressure to
air handler should be measured at the inlet of the air
handler gas manifold.
Minimum gas pressure as indicated on data plate
must be measured with the burner operating in high
fire.
Minimum inlet gas pressure is determined by gas
train size and BTU/h rating.
WARNING
Explosion Hazard
Leak test all components of gas piping
before operation.
Gas can leak if piping is not installed
properly.
Do not high pressure test gas piping with air
handler connected.
Failure to follow these instructions can result
in death, injury or property damage.
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