2.10.2 Manual Gas Shutoff Valve
A manual shut-off valve is factory-installed in the gas supply line at the unit, as shown in Figure
2.5. Additionally, if a gas regulator is installed upstream of the unit, refer to Figure 2.10.3.2 to
determine the location of the manual shut-off valve installation in relation to the regulator. The
maximum allowable gas pressure to the Water Heater is 14” W.C. (3.49 kPa).
2.10.3 External Gas Supply Regulator
An external gas pressure regulator is required on the gas inlet piping under most conditions
(see Sections 2.10.3.1 and 2.10.3.2, below). Regulators must conform to the following
specifications:
• The external natural gas regulator must be capable of regulating 50,000 BTU/Hr. to
3,180,000 BTU/Hr. (58.61 kW to 932.0 kW) of natural gas while maintaining a gas
pressure of 8.0” W.C. (1.99 kPa) minimum to the unit.
• A lock-up style regulator is required when gas supply pressure exceeds 14” W.C. (3.49
kPa).
2.10.3.1 Massachusetts Installations Only
For Massachusetts installations, a mandatory external gas supply regulator must be
positioned as shown in Figure 2.10.3.2, below. The gas supply regulator must be properly
vented to outdoors. Consult the local gas utility for detailed requirements concerning venting
of the supply gas regulator.
2.10.3.2 All Installations (Except Massachusetts)
An external gas supply regulator is recommended for all installations (other than
Massachusetts) that exceed 7” W.C. (1.74 kPa) gas pressure, positioned as shown in
Figure 2.10.3.2. No regulator is required for gas pressures below 7” W.C. (1.74 kPa) of
pressure. Consult the local gas utility for detailed requirements concerning venting of the
supply gas regulator.
Figure 2.10.3.2: Manual Gas Shut-Off Valve Location
NOTE:
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