User guide

16
042-288-B0-001, Rev. A2
Federal DOT Regulation 49 CFR Part 192.383, Excess Flow Valve Customer Notication, requires gas
utilities to either voluntarily install Excess Flow Valves (EFVs) on all new home service lines or to notify
builders about EFVs’ benets and availability. EFVs are installed on gas service lines during pre-construction
site work, and automatically activate when a gas line is ruptured. Excess ow valves should never be used as
in-line regulators. They cannot perform this function and may damage equipment.
Fig. 1-6, Excess Flow Valve
(above ground ¾" x 4" NPT nipple)
Alpha P/N 042-146-10
1.0 System Overview, continued
1.3 Natural Gas System Block Diagram
For added safety, a low pressure and high pressure excess ow valve may be installed.
Do not include the generator system as part of a local gas piping system test. Damage to the
generator pre-regulator may result. The generator system is pressure tested in accordance with
NFPA standards prior to shipment.
Fig. 1-5, Arrangement of Metered, Nominal Pressure (1-2psi) Natural Gas System
NOTE:
ATTENTION:
CAUTION!
S
CONTROL
CONTROLS
ENGINE
Demand
Low-pressure
Regulator
14" WC
(max.)
WC = Water Column H
2
O
Pre-Regulator
Maxitrol 325-3
10 psi max input
Flare Coupling
(Quick-Disconnect)
NOTE: 1 psi = 28" WC
0.5 psi (min.)
1 psi (nominal)
10 psi (max)
Engine must have
7" to 11" WC and 156 cubic
feet/Hr. to operate
Solenoid
APU
Enclosure
Meter
Manual
Shutoff
Low pressure excess
flow valve (optional)
High pressure
excess flow valve
(optional)