GROUP
FUEL SYSTEM
Technical Service Bulletin
SUBJECT:
DATE
December, 2020
NUMBER
20-FL-008H-1
MODEL(S)
NEXO FUEL CELL
(FE FCEV)
VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
This bulletin supersedes TSB# 20-FL-008H by revising the requirements for venting the
Hydrogen tank prior to conducting repairs.
Description:
This bulletin provides information on how to properly vent Hydrogen from a Nexo FCEV for
maintenance or repairs.
Applicable Vehicle: 2019-2020MY Nexo Fuel Cell
Warranty Information:
Normal Warranty Applies
Required Tools & Equipment
Portable Hydrogen Vent Stack (HVS01) Kit with Venting Manifold and Venting Hoses
Global Diagnostic Scan Tablet (GDS-M)
Vehicle Communication Interface II (VCI-II)
Hydrogen Gas Detector
Digital Volt Ohm Meter (DVOM)
Personal Protective Equipment
Watch/clock
Torque Wrench
19mm and 24 mm Combo Wrenches
Floor Jack, Wheel Chock, Jack Stands
Quick Connector Remover Tool
Various size metric sockets, 6mm hex socket Ratchet and extensions as needed
Tape Measure
Tapered Stopper
Reference Materials
Media Location
Hyundaitechinfo.com
Title
Nexo Service Manual
Hyundaitechinfo.com
TSB 20-FL-009H
Hyundaitechinfo.com
TSB 15-GI-001
Name / Description
Hydrogen Storage System
Portable Vent Stack
Assembly Procedure
ECU Update Procedure
For Tablet-Based GDS Mobile
Before Venting Questions/Considerations:
Is the venting procedure being completed at a pre-defined Hydrogen venting location?
Is a suitable grounding connection available, and in proper working condition?
Are the required tools, equipment and PPE ready, available and in proper working condition?
Has the desired venting endpoint of the tanks been determined based on type of repair?
Circulate To: General Manager, Service Manager, Parts Manager, Warranty Manager, Service
Advisors, Technicians, Body Shop Manager, Fleet Repair
SUBJECT
:
VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
Review the following venting requirements prior to conducting repairs on a Nexo FCEV.
Communicate with all applicable authority groups for additional venting requirements at your location.
Circumstances when venting Hydrogen from FCEV is necessary.
1. For routine maintenance work.
o Hydrogen storage tanks venting is not necessary so long as maintenance or repairs do not
involve; parts or components that may contain hydrogen (storage tanks, fill lines, delivery
lines, fuel cell) and/or the high voltage system components.
2. For maintenance/repair of Hydrogen system components (excluding Hydrogen storage
tanks and fill lines) and/or High Voltage system components.
o Hydrogen storage tanks pressure must be below 500psi.
3. For maintenance/repair of the Hydrogen storage tanks/fill lines; where open flame
activities or welding occurs within 18 inches (455 mm) of the Hydrogen storage tanks
and lines.
o Hydrogen tanks must be completely vented.
Follow the Hydrogen Storage Tanks Venting Procedure. (Page 4)
!
WARNING
Precautions when a Hydrogen leak is suspected
1. Move the vehicle outdoors.
2. Turn off all electrical equipment, eliminate possible ignition sources, open all windows/doors.
3. Use a hydrogen leak detector to find the cause of the leak.
4. Vent Hydrogen from the vehicle as needed for repairs.
5. Replace the component(s) as necessary to repair the leak.
6. After above procedures are completed, use suitable Hydrogen leak detector and recheck for
any Hydrogen leak.
This Fuel Cell Electric Vehicle (FCEV) utilizes up to 450 volts and compressed Hydrogen gas
stored up to 10,000 psi. Only qualified, trained technicians should perform the venting procedure.
Before performing the service procedure, ensure the proper Personal Protective Equipment
(PPE) is worn to prevent injury. Verify PPE is not expired and in proper working condition.
!
CAUTION
When replacing any of the hydrogen storage system components, there may be leakage in the
connecting part. Inspect for Hydrogen leaks after repairing / replacing any component that is part of
the Hydrogen system. (Refer to Hydrogen Storage System – “General Information”)
TSB #: 20-FL-008H-1
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VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
Manifold Assembly:
Review the function of each Manifold Assembly component before performing this service procedure.
The reference picture below outlines the basic function(s) of the manifold assembly.
TSB #: 20-FL-008H-1
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VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
Hydrogen Storage Tanks Venting Procedure:
A. Portable Hydrogen Vent Stack (HVS01) Kit
1.
Assemble the portable Hydrogen Vent Stack Part Number (HVS01) using TSB 20-FL-009H.
Locate the FCV Venting Manifold Kit which includes the following:
Kit Contents –
Manifold Assembly
Auxillary gas hose
Three 10 foot long venting
hoses
Do not connect any part of the Portable Hydrogen Vent Stack, Venting Manifold, or Venting
hose to any other venting system used for any other purpose
When using the Portable Vent Stack, follow the minimum spacing distances.
Feet
2
5
5
10
15
17
20
40
Minimum Spacing From Hydrogen Vent Exit.
Above adjacent equipment
Above rooftops
Spherically, to Class 1, Division 1 Electrical Classification
Grade level to hydrogen vent exit
Spherically, to Class 1, Division 2 Electrical Classification
Overhead utilities; Non-fire-rated buildings; Flammable, combustible or
other hazardous materials process or storage systems
Exposed persons and parked cars
Lot lines; Air intakes; Building/Structure opening; Open flames or welding.
Ensure the Portable Vent Stack is properly grounded.
TSB #: 20-FL-008H-1
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VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
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B. Vehicle Preparation and Staging:
!
WARNING
Do not vent Hydrogen during electrically conductive weather conditions.
NOTICE
Before performing the service procedure, verify that the GDS-M is adequately charged.
1.
In an outdoor area approved for Hydrogen venting, the vehicle must be 15 feet or greater from
the assembled and properly grounded Portable Hydrogen Vent Stack. The vehicle must be
outside the coned off safety circle.
While the vent hose is connected to the manifold assembly, no personnel should be allowed
into the safety circle.
2.
If the vehicle has been in storage for several days, run the fuel cell for a sufficient amount of
time to ensure that the 12 volt battery is fully charged.
3.
Ensure that the 12 volt battery will not become discharged during the venting procedure by
turning off all lights and accessories including heater/air conditioner, fan, audio, heated seats,
rear defroster, etc.
4.
Do not leave the headlight switch in auto mode.
5.
Place the vehicle in park.
6.
7.
Apply the parking brake, roll down the windows as necessary, and open the rear hatch.
Scan and record all DTCs before performing service procedure.
8.
Ensure the Push Button Start Stop (PBSS) is off, and the fuel stack is not in Ready Mode.
Wait at least 3 minutes, and use appropiate PPE before proceeding to Section C.
TSB #: 20-FL-008H-1
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VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
C. 12 Volt and High Voltage Circuit Disconnection
1.
In the rear cargo area, remove the floorboard and cargo tray to access the 12 volt battery
connector and high voltage battery Safety Plug.
2.
Disconnect the 12 volt battery negative (-) connector.
!
WARNING
Before performing the service procedure, ensure proper Personal Protection Equipment (PPE)
is worn to prevent injury. Verify PPE is not expired and in proper working condition.
TSB #: 20-FL-008H-1
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VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
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3.
Remove the metal shield to access the High Voltage Safety Plug.
4.
Follow 1- 4 below to remove the orange high voltage safety plug.
Store the removed safety plug in a secure location outside and away from the vehicle.
Safety Plug Removal
Safety Plug Removal
1
3
5.
Press down on the safety
plug lever
2
Pull the green safety plug
lock tab
4
Remove the safety plug
Wait 5+ minutes to allow the high voltage system capacitor to discharge.
NOTICE
The High Voltage Junction Box (HVJB) cover is located under the hood and on top of
the fuel stack in the fuel cell compartment.
!
DANGER
The High Voltage Junction Box (HVJB) may be electrically energized up to 450 volts.
TSB #: 20-FL-008H-1
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6.
VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
Remove the junction box trim and cover.
HVJB Cover
Junction Box Trim
High voltage junction box cover: Assembly bolt torque. 9.8 - 11.8 N.m (1.0 - 1.2 kgf.m, 7.2 - 8.7 lb-ft
7.
Using a Digital Volt Ohm Meter (DVOM), measure the voltage across the inverter positive and
negative bus bar terminals to inspect for capacitor discharge. If the measured voltage is
below 30V, the High Voltage Circuit is properly shut down.
-_
Measure Voltage
Here
+
D. Hydrogen Tank Valves Shut-Off
1.
Place wheel chocks to both front and rear passenger side wheels.
2.
Using a floor jack or suitable equipment, slightly raise the driver’s side of the vehicle to allow
for attachment of the Vent Manifold Assembly.
3.
Ensure the vehicle is securly supported. Use devices such as jack stands that are load rated
to safely support the Nexo.
4.
Remove the vehicle under covers to access the Hydrogen Tank Valves and High Pressure
Regulator. See service manual Nexo(Fe) > Hydrogen Storage System > Hydrogen Tank >
Repair procedures.
Floor under cover bolt torque : 7.8 - 11.8 N.m (0.8 - 1.2 kgf.m, 5.8 - 8.7 lb-ft
TSB #: 20-FL-008H-1
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VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
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5.
Close the manual valves on all three Hydrogen storage tanks using a 6mm hex socket (turn
clockwise) until fully seated in the closed position (flush with the valve body).
Manual Valve Locations
Manual Valve in Open Position
Manual Valve Operation
Manual Valve in Closed Position
E. Residual Pressure Release in Fuel Supply Line
1.
Unscrew the plug located in the Service Purge Valve at the High Pressure Regulator (HPR).
TSB #: 20-FL-008H-1
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2.
VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
Screw the Pressure Release Adapter into the Service Purge Valve.
Ensure the Pressure Release Adapter is fully seated in the Service Purge Valve.
HPR
Service
Purge
Valve
3.
Verify that both Manifold Assembly ball valves are closed.
Connect the Manifold Assembly to the Pressure Release Adapter quick disconnect.
Connect the vent stack hose to the Manifold Assembly red quick disconnect.
Ball Valves in Closed Position
Discharge Hose
to Vent Stack
Pressure Release
Adapter Quick
Disconnect
Red Quick Disconnect
While the vent hose is connected to the manifold assembly, no personnel should be allowed
into the safety circle
4.
Connect the discharge hose from the Manifold Assembly to the vent stack. Do not connect to
the discharge hose to any other venting system used for any other purpose.
TSB #: 20-FL-008H-1
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5.
VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
While holding the upper nut (24mm), turn the lower nut (19mm) on the Service Purge Valve
counter clockwise until the lower nut stops turning to open the service purge valve.
Service
Purge
Valve
6.
Using a Hydrogen leak detector, check for Hydrogen leaks at the fitting between the Service
Purge Valve and Manifold Assembly. Refer to the warning on Page 2 if a leak is suspected.
7.
Open the Manifold Assembly ball valve located in line with the Pressure Release Adapter and
a momentary hiss sound will be heard. After the hissing sound stops, close the Service Purge
Valve, then close the opened Manifold Assembly ball valve.
Closed Position
To Vent
Stack
Flow Path
from Service
Purge Valve
Turn
Counterclockwise to
Open Ball Valve
8.
Remove the Manifold Assembly and Pressure Release Adapter, then reinstall the Service
Purge Valve plug back into the Service Purge Valve.
F. Hydrogen supply tube disconnection using the release tool
1.
Slide the lock mechanism backwards employing a gentle rocking motion using needle nose
pliers or hands.
Hydrogen
Supply Tube
Lock Mechanism
Lock
Mechanism
Lock Mechanism
TSB #: 20-FL-008H-1
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2.
VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
Follow the instructions below to properly remove the Hydrogen supply tube.
Quick
Connector
Remover Tool.
See page 3.
1
Install the quick connector remover
tool onto the fuel pipe.
High Pressure
Regulator Fitting
2
Slide the quick connector remover tool into the High
Pressure Regulator Fitting until a click can be heard.
Tapered
Stopper
Hydrogen
Supply Tube
3
Pull the Hydrogen Supply tube out of the
High Pressure Regulator Fitting.
4
Install a clean stopper into the Hydrogen
supply tube to prevent contamination
G. Hydrogen Tank Venting
1.
NOTICE
Verify that both Manifold Assembly ball valves are closed.
Insert the Manifold Assembly vent tube into the High Pressure Regulator fitting where the
Hydrogen supply tube was removed. A clicking sound will be heard when the tube is fully
engaged and locked into the High Pressure Regulator Fitting. Pull back on the Manifold
Assembly vent tube to verify that the tube is locked into the High Pressure Regulator Fitting.
High Pressure
Regulator Fitting
Manifold Assembly
Vent Tube
TSB #: 20-FL-008H-1
A clicking sound will be
heard when engaged
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VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
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2.
Using a 6mm male hex socket, turn the manual valve counterclockwise until the valve stops.
Fully reopen the manual valves on all three Hydrogen Storage Tanks.
Manual Valve in Closed Position
Manual Valve Operation
Manual Valve in Open Position
Manual Valve Locations
3.
Reconnect the auxiliary 12V battery negative (-) connector located in the rear cargo area.
4.
Press the Start/Stop button twice (Do not depress the brake pedal) to turn on the electrical
system (Accessory Mode). Do not start the fuel cell.
5.
Ensure the Hyundai GDS-M has the latest software update per TSB 15-GI-001 and that GDS
is fully charged.
Connect the GDS-M to the vehicle, select HMU (Hydrogen Management Unit). From Data
Analysis, select high pressure sensor, tank temperature for Front, Mid, Rear tanks.
Perform the HMU actuation tests (All Tank Valve Open).
TSB #: 20-FL-008H-1
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VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
Monitor tank temperature and pressure during the venting procedure, and graph Tank
Pressure and Tank Temperature for the Front, Mid, and Rear tanks.
6.
Gradually open the Manifold Assembly ball valve until the valve handle points to the red
discharge hose fitting. Regulate the venting flow with this valve.
Using a Hydrogen leak detector, inspect for Hydrogen leaks at all fittings between the Service
Purge Valve and Vent Stack Assembly. If Hydrogen leaks are suspected, stop (turn off) tank
valve actuation, allow Hydrogen to disperse then correct leak(s). Resume venting, repeat leak
check of fittings between the Service Purge Valve and Vent Stack Assembly.
(Arrow shape of ball valve handle points in direction of gas flow)
Hydrogen gas flows from Hydrogen
storage tanks to vent stack
Flow Path
Closed
Turn counterclockwise to open valve
and to adjust venting flow rate.
Use the Manifold Assembly ball valve to regulate the venting rate to depressurize the tanks at
145psi per minute, typically 1.55-1.65 MPa indicated on the manifold pressure gauge when
the tank pressure reads 435 psi on the GDS-M.
Monitor the tank pressure on the GDS-M, and adjust the venting rate so that the tank
depressurizes at 7 psi per minute using a watch with minute readout.
TSB #: 20-FL-008H-1
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VENTING NEXO FUEL CELL ELECTRIC VEHICLES (FCEV)
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Typical range
during defueling
If the tank temperature approaches -40F, stop venting or reduce the venting rate to maintain
tank temperature above -40F.
NOTICE
Vent tanks at 145 psi per minute until 435 psi is reached, then reduce venting rate to 7
psi per minute.
7.
Once the tanks have been vented to the desired amount, stop the actuation test and remove
the Manifold Assembly Vent Tube.
Reinstall the Hydrogen supply tube to the High Pressure Regulator fitting and install the
Hydrogen supply tube lock mechanism.
Using a Hydrogen leak detector, check for Hydrogen leaks at the HPR fittings and any repair
involving any part of the Hydrogen system.
8.
Reinstall all parts in reverse order of removal.
9.
Scan and clear DTCs in all systems.
10.
The service procedure is now complete.
TSB #: 20-FL-008H-1
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