HEIL PT 1000, Operation Manual

Page: 179 / 202

Issued September 2017
Compressed Natural Gas (CNG) Option Copyright 2017, Heil Environmental
Printed in U.S.A.
171
TRANSFER FUELING (DEFUELING) MODES,
COMPONENTS AND PROCEDURES
(CONTINUED)
1. Defueling to Another Vehicle (Continued)
f. Connect the hose’s fueling nozzle to the NGV1
fueling receptacle on the receiving (fueling)
vehicle.
g. Turn the defueling control valve on the supplying
(defueling) vehicle to “Defueling Enabled”. This
will initiate the flow of CNG fuel from the supplying
vehicle to the receiving vehicle.
h. To stop the flow of CNG fuel, turn the Defueling
Control Valve to the “Normal Operation” position.
This will stop the flow of CNG fuel and vent the
pressure in the defueling hose so that it can be
disconnected. If the supplying vehicle is not
equipped with a defueling control valve which
automatically vents the pressure in the hose when
the flow of CNG fuel is stopped, then the purge
valve must be used to vent the hose, allowing
disconnection of the hose from the receptacle.
2. Atmospheric Venting Method
a. You must first check to see if this method is legal
in your area. There could be local environmental
regulations regarding the release of methane into
the atmosphere.
b. If atmospheric venting is acceptable in your area,
then a vent stack apparatus that meets the
requirements established in either the Uniform
Building Code or the International Building Code
must be followed as well as NFPA 52.
c. With the local authority having jurisdiction,
typically the Fire Marshal should be consulted.
d. BOTH the vehicle AND the fuel system should be
grounded. Use a minimum 14-gauge multi-
stranded wire. Contact the CNG system
manufacturer for attachment points for the ground
wire.
e. Restrain all tanks during depressurization to
prevent the tanks from moving.
f. Attach a defueling nozzle to the defueling
receptacle. Contact the CNG system
manufacturer for the minimum distance the vent
hose should be positioned above the ground.
g. After this nozzle is connected, the valves that
allow system pressure to reach the defueling
receptacle must be turned to the "defueling
enabled" position (if equipped).
3. Compressor Inlet Method
a. This procedure requires pre-planning and special
equipment installed at the CNG fueling station.
Check with your CNG fueling station supplier or
installer.
b. In this method, the vehicle is connected through
the fueling nozzle to the defueling panel
receptacle and the compressor at the fueling
station extracts the compressed natural gas from
the vehicle.