FCCC MT-45 MT-55 CNG FUEL SYSTEM
P80 - P100 - P120 USER MANUAL
USM.0004 Ver. 1.0
April 4, 2022

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Table of Contents
I.

Proprietary Statement .................................................................... 4

II.

Trademark Notice ........................................................................... 4

III. Preface ............................................................................................ 5
IV. Warning Statements Used in this Manual..................................... 6
V.

Support, Service or Parts .............................................................. 7

VI. Introduction .................................................................................... 9
1.

Safety .............................................................................................11

2.

Operation .......................................................................................31

2.1. Pre-Trip Inspection........................................................................31
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2.2. Fuel System ...................................................................................35
2.3. Engine Starting ..............................................................................43
2.4. Vehicle Fueling ..............................................................................44
3.

Service and Maintenance ..............................................................51

3.1. Recommended Fluids ...................................................................51
3.2. Maintenance Schedule ..................................................................53
4.

Warranty ........................................................................................57

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I.

Proprietary Statement

The information provided within this document is proprietary and confidential. All prior
versions, including updates and revisions forwarded separately, are also proprietary and
confidential. The information provided by Hexagon Agility Inc. and its subsidiaries
(collectively Hexagon Agility®), to its customers is solely for the use of those customers. No
portion of this manual may be reproduced or distributed without prior written consent of
Hexagon Agility®. Hexagon Agility® reserves all rights, including intellectual property rights,
contained within this publication.
Portions of this manual drawn from information provided by Hexagon Agility® suppliers are
used with permission.

II.

Trademark Notice

Hexagon® is a registered trademark of Hexagon Technology AS. Agility® is a registered
trademark of Agility Fuel Solutions LLC.

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III.

Preface

This manual contains the latest information available at time of publication and is offered for
download from Hexagon Agility®. Hexagon Agility® reserves the right to make future
changes in products or information contained in this manual without prior notice.
This manual contains general safety, operation, maintenance, and inspection information
for the Hexagon Agility® compressed natural gas (CNG) fuel system. Refer to the original
equipment manufacturer (OEM) operation manual or service publications for information on
non-Hexagon Agility® systems or components.
No attempt should be made to operate, fill, install, or maintain the fuel system until this
manual and all referenced supporting documentation are read and understood.

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IV. Warning Statements Used in this Manual
.⚠ WARNING.

Personal injury or death may occur if procedures are not followed.

.⚠ CAUTION.

Damage to equipment, engine, fuel system or vehicle is possible if instructions are
not followed.

NOTICE .

Best practices or hints to help an operation or procedure go smoothly.

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V. Support, Service or Parts
Hexagon Agility® prides itself on supporting its customers after the sale. We offer complete
service support to our customers.
When calling or emailing, please provide your name, phone number, email address, and
complete vehicle information: VIN, year, make, model, mileage, and its current location.
A service advisor will contact you to arrange vehicle repair or a ship a part.

Customer Care
+1-833-4-HEX-CARE
UPS Direct Access Prompt: 6
[email protected]
[email protected]

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Hexagon Agility
3335 Susan Street
Suite 100
Costa Mesa, CA 92626
www.hexagonagility.com

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VI. Introduction

This vehicle is equipped with a Hexagon Agility® fuel system built for medium duty natural
gas vehicle (NGV) applications. The engine and fuel system are designed to operate on
compressed natural gas (CNG) and/or renewable natural gas (RNG). Natural gas is an
abundant, clean burning, readily available domestic fuel with the benefits of significantly
reduced greenhouse gas emissions and lower operating costs
This manual is an operator’s reference guide providing general instructions to ensure proper
operation and maintenance of the Hexagon Agility® fuel system. Proper fuel system
maintenance and operation are vital to vehicle up time and user satisfaction. Procedures
outlined within this manual are a supplement to Hexagon Agility® service manuals
developed for trained service personnel. Failure to adhere to these procedures may void
fuel system warranty.
Refer to original equipment manufacturer (OEM) operation manual or service publications
for information on systems or components not supplied by Hexagon Agility®.

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.⚠ WARNING.

This manual is intended as a supplement to formal training in operation and
maintenance of CNG fuel systems.

.⚠ WARNING.

No attempt shall be made to operate, fill, maintain, or repair the CNG fuel system until
this manual and all referenced supporting documentation have been read and fully
understood.

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1. Safety
1.1. Natural Gas Facts
1. Natural gas is flammable. However, natural gas only burns within a narrow range
when mixed with air in a ratio of between 5 and 15 percent. Compressed natural gas
(CNG) will not burn in the highly concentrated form found inside fuel system cylinders.
2. Natural gas is odorless, tasteless, and non-toxic. Mercaptan is injected into CNG
to give it a “rotten egg” odor to aid leak detection.
3. Natural gas is lighter than air; because of this property, CNG rises and diffuses
into the atmosphere when released.
4. Natural gas has an octane rating of 130.
5. Renewable natural gas (RNG) or “biogas” resulting from the decomposition of
organic matter under anaerobic conditions reduces reliance on fossil fuels and
diversifies domestic energy production.

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1.2. CNG Pressure Safety Precautions
CNG possesses unique hazards which are not present in gasoline or diesel fuel. Unlike
gasoline and diesel which are liquids at room temperature and pressure, CNG is in a
gaseous state under the same conditions. For storage purposes, natural gas must be
compressed to 3600 psi (250 bar). Hexagon Agility® minimizes these potential hazards with
state-of-the-art design and testing practices.
Normal CNG Fuel System Pressure Ranges
Minimum
Maximum
High Pressure
3600 psi (250 bar)
4000 psi (275 bar)
Low Pressure
120 psi (8.2 bar)
150 psi (10.3 bar)

.⚠ WARNING.

 Memorize manual shutoff valve location(s) (FIGURE 1) and normal CNG system
pressure ranges.
 If anything does not look correct, notify maintenance personnel immediately.
Turn ignition switch OFF, turn 1/4-manual shutoff valve (FIGURES 1 and 2) to the
CLOSED position and set parking brake.

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valve
handle
frame
rail

valve in CLOSED position

valve in OPEN position

FIGURE 1. 1/4-turn manual shutoff valve is located driver side chassis rail.
Rotate handle clockwise to CLOSE; counterclockwise to OPEN.

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1.3. Qualified Personnel
Due to the presence of high-pressure and flammable fuel, CNG fuel systems are a form of
hazardous energy storage requiring special training for safe operation.

.⚠ WARNING.

Hexagon Agility® fuel systems must be maintained and inspected exclusively by
qualified trained personnel.

.⚠ WARNING.

Never attempt to service the Hexagon Agility® fuel system. The fuel system operates
under high pressure; injury could result, and vital system components can be
damaged. Service should be only performed by Hexagon Agility® certified Authorized
Service Providers.

.⚠ WARNING.

Have vehicle towed to repair facility. Refer to Section 1.10.

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FRONT

KEY: HP fuel lines ▬ LP fuel lines ▬ PRD vent lines ▬ DS – driver side PS – passenger side

manual shutoff valve

2

LP flexible
fuel hose

HP fuel cross
over tube

8

9

7
6

5

4

3

2

manual shutoff valve

1

HP flexible fuel hose

FIGURE 2. FCCC MT CNG fuel system components
1 fuel fill panel
4 HP fuel filter
2 CNG cylinders
5 solenoid supply valve
3 1/4-turn manual shutoff valve
6 pressure regulator
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7 LP fuel filter
8 fuel rail assembly
9 plug PRDs
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1.4. Vehicle Safety Precautions
The following safety precautions must be observed when operating CNG vehicles and
fueling equipment:
1. A portable fire extinguisher must be installed on the vehicle in an easily accessible
location.
2. Do not start engine if a fuel leak is suspected.
3. Do not smoke or produce an open flame within 30 feet (9 m) of a CNG vehicle or
dispensing/filling station.
4. Never attempt to open pressurized system components.
5. Always ground vehicle prior to defueling.
6. If vehicle must be out of service for an extended period, turn cylinder manual shutoff
valves to the “OFF/CLOSED” position and run the engine until it stalls to consume
residual fuel in lines. FIGURE 2

NOTICE.
Observe any lockout-tagout (LOTO) guidelines.
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KEY: PRD vent lines ▬ DS – driver side PS – passenger side
cylinder shield
FRONT

plug PRD

integral valve PRD

PRD vent cap

PS cylinder

pressure
regulator
PRV port
and cap

integral valve PRD

DS cylinder

plug PRD

cylinder shield

FIGURE 3. FCCC MT CNG pressure relief device (PRD) locations and PRD vent line routing (green lines)
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1.5. CNG Cylinder Safety
Each individual CNG fuel cylinder has a manual shutoff valve at one end which allows the
fuel in that cylinder to be isolated from the rest of the system. During normal operation, all
cylinder manual shutoff valves should be OPEN. FIGURE 1
This vehicle is equipped with temperature activated pressure relief devices (PRDs) to
evacuate stored fuel safely in the event of a thermal event. PRDs trigger when cylinder(s)
surroundings or internal enclosure temperatures exceed 212°F (100°C) to 220°F (110°C)
and use vent lines which exit to the vehicle rear to evacuate the pressurized gas.* The PRD
vent system design permits controlled fuel evacuation/flaring under certain environmental
conditions. FIGURE 3

.⚠ WARNING.

Memorize manual shutoff valve locations. FIGURES 1 and 2

NOTICE.
Check permanent labels on CNG cylinders to verify OEM and expiration date.
*Refer to Section 2.2.1.
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1.6.
1.
2.
3.
4.

Emergency Shut Down Procedure

Turn ignition switch OFF.
Set parking brake.
If equipped and if it safe to do so: turn OFF main battery disconnect switch.
if it safe to do so Turn red 1/4-turn manual shutoff valve on driver side chassis frame
rail to the OFF/CLOSED position. FIGURES 1 and 2

.⚠ WARNING.

If vehicle is involved in an accident or fire, CNG fuel system must be inspected by a
qualified fuel system inspector.

NOTICE.
Refer to Hexagon Agility® “First Responder Guide,” ENP-084, for CNG firefighter
information.

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1.7. Emergency Response for Gas Leaks
If vehicle has sustained damage or a gas leak is suspected, i.e., a persistent “rotten eggs”
odor is present or a continual hissing sound is heard, it could be a natural gas leak. If gas
ignites, injury or death could result.

.⚠ WARNING.
1.
2.
3.
4.
5.

Do not attempt to start vehicle.
Do not smoke or allow anyone else to smoke near the vehicle.
Evacuate area and keep traffic and pedestrians away.
Do not use road flares.
Do not approach vehicle if any ignition sources such as fire, sparks, electrostatic
charges, lights, or electronic devices may be present.
6. If ignition sources may be present, vehicle doors and compartments should remain
closed.
7. If no ignition sources are present, open vehicle doors and compartments to prevent gas
accumulation.

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8. If vehicle is indoors, push or tow vehicle outside and away from any ignition sources.
Open building windows and doors to allow ventilation. Avoid turning on any lights, fans,
or electronics which may spark. Pay special attention to overhead sources of ignition
since natural gas is lighter than air.
9. Turn ignition switch OFF, set parking brake, and turn battery OFF at main disconnect
switch.
10. If it is safe to do so, close 1/4-turn manual shutoff valve and both cylinder manual
shutoff valves. FIGURES 1 and 2. Beware that gas may continue to leak with ignition OFF
and manual shutoff valves closed.

.⚠ WARNING.

NEVER use a flame to detect natural gas.
11. If it is safe to do so, check fuel system near damaged area for leaks by smell (rotten
egg odor), sight (ice or bubble formation), and sound (audible hiss). Verify leak
location(s) with Swagelok® Snoop® leak detection fluid.

.⚠ WARNING.

Fuel system leaks must be repaired by a qualified technician.
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1.8.
1.
2.
3.