SERIES 2000 INSTALLATION, OPERATION AND SERVICE MANUAL
42
15.4 Gas Piping
The gas manifold extends through the side of the
control cabinet for models 2005 - 2030. The factory
piping terminates with a male pipe connection. A
union must also be installed (supplied by others)
between the manual gas valve main and the first tee
pipe. Be sure that the fuel supply pipe connected at
this point is large enough to ensure the proper gas
flow and line pressure at the inlet of the air handler.
The piping 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.
Gas supply piping must conform to best building
practices and local codes. During installation of the
gas piping, be sure that no piping restricts
accessibility to the air handler or its removable
access doors.
Lockable manual shut-off valve must be added by the
installer in compliance with Occupational Safety and
Health Administration (OSHA) regulations.
15.5 Pressure Test Ports
There are 1/8" (3.2 mm) and 1/4" (6.4 mm) pressure
test ports located on the manifold. The test ports are
av
ailable to measure the manifold inlet gas pressure
and the burner gas pressure during burner setup.
15.5.1 Manifold Inlet Gas Pressure
The pressure port for measuring manifold inlet
pressure is located on the inlet side of the first safety
shutoff valve. Refer to the unit rating plate for the
acceptable inlet gas pressure.
15.5.2 Burner Gas Pressure
A pressure tap is used to measure negative airflow at
the burner and to set high fire gas pressure. On air
handlers equipped with a M611 modulating valve, the
pressure tap is located on a tee between the M611
valve and the burner. See Page 42, Figure 22 and
Page 71, Figure 36. On air handlers equipped with
the MR212 modulating valve, the pressure tap could
be located on the downstream side of the MR212
val
ve, on a T-fitting coming off the outlet pressure tap
on the MR212 valve or between the MR212 valve
and the burner. See Page 42, Figure 22 and Page
70, Figure 34.
FIGURE 22: Plug Tapping (2005 - 2030)
15.6 Line Pressure Test - Leak Testing
The air handler and its individual shut-off valve must
be disconnected from the gas supply piping systems
during any pressure testing of that system at test
pressures in excess of 14 in wc (34.9 mbar). The air
handler must be isolated from the gas supply piping
system by closing its individual manual gas valve that
is located immediately upstream of the safety shut-off
gas valve.
Burner
Modulating Valve
Manual Gas
Valve (Burner)
Plugged Taping
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