Issued September 2017
Compressed Natural Gas (CNG) Option
Copyright 2017, Heil Environmental
Printed in U.S.A.
170
TRANSFER FUELING (DEFUELING) MODES,
COMPONENTS AND PROCEDURES
(CONTINUED)
3. Defueling Hose
a. The Defueling Hose (if available) is to be used for
the purpose of transferring CNG fuel from a
supplying (defueling) vehicle to a receiving
(fueling) vehicle.
b. The tank pressure of the supplying vehicle must
be higher than the tank pressure of the receiving
vehicle in order for CNG fuel to transfer.
c. Once the two (2) vehicles’ tank pressures have
equalized due to the transfer of CNG fuel, no
further transfer of CNG fuel will occur.
d. In order to use the Defueling Hose, the vehicle
being defueled must be equipped with a defueling
receptacle.
e. If the vehicle is not equipped with a defueling
receptacle, then the defueling operation is not
possible using the Defueling Hose Assembly.
E. CNG Fuel Module Defueling Methods
There are three methods by which to defuel a CNG
vehicle using a Defueling Panel with a Defueling
Receptacle. If your unit has the
System
option, the ignition must be left ON while
defueling in order for all tanks to defuel. See
section for more
information.
WARNING
Venting does not completely empty the system of
combustible gas. Never weld on a compressed natural gas
vehicle unless the compressed natural gas fuel system
has been purged with inert gas. See
.
1. Defueling to Another Vehicle
a. Prior to connecting the defueling hose to either
vehicle, open the purge valve on the hose to
release any residual pressure that may be in the
hose.
b. Close the purge valve and continue.
c. Position the defueling control valve on the fuel
module in the “Normal Operation” position. This
will release any pressure in the defueling circuit
and allow the hose’s defueling nozzle to be
connected to the defueling receptacle.
d. If the valve is not in this position, it will not be
possible to make the connection.
e. Connect the hose’s defueling nozzle to the
defueling receptacle of the fuel module on the
supplying (defueling) vehicle.
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Summary of Contents for PT 1000
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