Woodward L-Series User manual

Product Manual 35144
(Revision -, 07/2019)
Original Instructions
L-Series ITB / LC-50
RoHS Compliant
Installation and Operation Manual
Released

General
Precautions
Read this entire manual and all other publications pertaining to the work to be
performed before installing, operating, or servicing this equipment.
Practice all plant and safety instructions and precautions.
Failure to follow instructions can cause personal injury and/or property damage.
Revisions
This publication may have been revised or updated since this copy was produced.
To verify that you have the latest revision, check manual 26455, Customer
Publication Cross Reference and Revision Status & Distribution Restrictions, on
the publications page of the Woodward website:
www.woodward.com/publications
The latest version of most publications is available on the publications page. If
your publication is not there, please contact your customer service representative
to get the latest copy.
Proper Use
Any unauthorized modifications to or use of this equipment outside its specified
mechanical, electrical, or other operating limits may cause personal injury and/or
property damage, including damage to the equipment. Any such unauthorized
modifications: (i) constitute "misuse" and/or "negligence" within the meaning of
the product warranty thereby excluding warranty coverage for any resulting
damage, and (ii) invalidate product certifications or listings.
Translated
Publications
If the cover of this publication states "Translation of the Original Instructions"
please note:
The original source of this publication may have been updated since this
translation was made. Be sure to check manual 26455, Customer Publication
Cross Reference and Revision Status & Distribution Restrictions, to verify whether
this translation is up to date. Out-of-date translations are marked with . Always
compare with the original for technical specifications and for proper and safe
installation and operation procedures.
Revisions—A bold, black line alongside the text identifies changes in this publication since the
last revision.
Woodward reserves the right to update any portion of this publication at any time. Information provided by Woodward is
believed to be correct and reliable. However, no responsibility is assumed by Woodward unless otherwise expressly
undertaken. Manual 35144
Copyright © Woodward, Inc. 2019
All Rights Reserved
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Manual 35144 L-Series ITB / LC-50 RoHS Compliant
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Contents
WARNINGS AND NOTICES .......................................................................... 3
ELECTROSTATIC DISCHARGE AWARENESS................................................. 4
REGULATORY COMPLIANCE....................................................................... 5
CHAPTER 1. GENERAL INFORMATION ......................................................... 7
Purpose and Scope................................................................................................7
Intended Applications .............................................................................................7
L-Series Description ...............................................................................................7
Determining Proper Valve Size ..............................................................................8
CHAPTER 2. APPLICATION OVERVIEW ...................................................... 11
Hardware Configuration Application Process.......................................................11
CHAPTER 3. INSTALLATION...................................................................... 13
Mechanical Installation .........................................................................................14
LC-50 Applications (Mixer Applications)...............................................................20
CHAPTER 4. TROUBLESHOOTING ............................................................. 22
CHAPTER 5PRODUCT SUPPORT AND SERVICE OPTIONS ........................... 23
Product Support Options......................................................................................23
Product Service Options.......................................................................................23
Returning Equipment for Repair...........................................................................24
Replacement Parts...............................................................................................24
Engineering Services............................................................................................25
Contacting Woodward’s Support Organization ....................................................25
Technical Assistance............................................................................................26
L-SERIES ITB SPECIFICATIONS................................................................ 27
APPENDIX.ACRONYMS/ABBREVIATIONS................................................... 28
REVISION HISTORY.................................................................................. 29
DECLARATIONS....................................................................................... 30
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Illustrations and Tables
Figure 1-1. Cv vs Angle for L-Series ITBs..............................................................9
Figure 1-2. Cv vs Angle for L-Series Trim Valves................................................10
Figure 2-1. Application Matrix...............................................................................11
Figure 3-1. Spring-Loaded Throttle Plate.............................................................15
Figure 3-2. L-Series ITB Outline Drawings...........................................................17
Figure 3-3a. LC-50 Outline Drawing (small bore).................................................18
Figure 3-3b. LC-50 Outline Drawing (large bore).................................................19
Figure 3-4. Zirconia Oxygen Sensor Response...................................................21
Figure 3-5. Pre-Catalyst Emissions......................................................................21
Figure 3-6. Post-Catalyst Emissions ....................................................................21
Table 1-1. Cv (Flow Coefficient).............................................................................8
Table 3-1. MAS and ZPR Initial Settings..............................................................20
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Warnings and Notices
Important Definitions
This is the safety alert symbol used to alert you to potential personal injury hazards. Obey all
safety messages that follow this symbol to avoid possible injury or death.
DANGER - Indicates a hazardous situation, which if not avoided, will result in death or serious injury.
WARNING - Indicates a hazardous situation, which if not avoided, could result in death or serious
injury.
CAUTION - Indicates a hazardous situation, which if not avoided, could result in minor or moderate
injury.
NOTICE - Indicates a hazard that could result in property damage only (including damage to the
control).
IMPORTANT - Designates an operating tip or maintenance suggestion.
Overspeed /
Overtemperature /
Overpressure
The engine, turbine, or other type of prime mover should be
equipped with an overspeed shutdown device to protect against
runaway or damage to the prime mover with possible personal injury,
loss of life, or property damage.
The overspeed shutdown device must be totally independent of the
prime mover control system. An overtemperature or overpressure
shutdown device may also be needed for safety, as appropriate.
Personal Protective
Equipment
The products described in this publication may present risks that
could lead to personal injury, loss of life, or property damage.
Always wear the appropriate personal protective equipment (PPE) for
the job at hand. Equipment that should be considered includes but is
not limited to:
Eye Protection
Hearing Protection
Hard Hat
Gloves
Safety Boots
Respirator
Always read the proper Material Safety Data Sheet (MSDS) for any
working fluid(s) and comply with recommended safety equipment.
Start-up
Be prepared to make an emergency shutdown when starting the
engine, turbine, or other type of prime mover, to protect against
runaway or overspeed with possible personal injury, loss of life, or
property damage.
Automotive
Applications
On- and off-highway Mobile Applications: Unless Woodward's
control functions as the supervisory control, customer should install
a system totally independent of the prime mover control system that
monitors for supervisory control of engine (and takes appropriate
action if supervisory control is lost) to protect against loss of engine
control with possible personal injury, loss of life, or property
damage.
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Battery Charging
Device
To prevent damage to a control system that uses an alternator or
battery-charging device, make sure the charging device is turned off
before disconnecting the battery from the system.
Electrostatic Discharge Awareness
Electrostatic
Precautions
Electronic controls contain static-sensitive parts. Observe the
following precautions to prevent damage to these parts:
Discharge body static before handling the control (with power to
the control turned off, contact a grounded surface and maintain
contact while handling the control).
Avoid all plastic, vinyl, and Styrofoam (except antistatic
versions) around printed circuit boards.
Do not touch the components or conductors on a printed circuit
board with your hands or with conductive devices.
To prevent damage to electronic components caused by improper
handling, read and observe the precautions in Woodward manual
82715, Guide for Handling and Protection of Electronic Controls,
Printed Circuit Boards, and Modules.
Follow these precautions when working with or near the control.
1. Avoid the build-up of static electricity on your body by not wearing clothing made of synthetic
materials. Wear cotton or cotton-blend materials as much as possible because these do not store
static electric charges as much as synthetics.
2. Do not remove the printed circuit board (PCB) from the control cabinet unless absolutely necessary.
If you must remove the PCB from the control cabinet, follow these precautions:
Do not touch any part of the PCB except the edges.
Do not touch the electrical conductors, the connectors, or the components with conductive
devices or with your hands.
When replacing a PCB, keep the new PCB in the plastic antistatic protective bag it comes in
until you are ready to install it. Immediately after removing the old PCB from the control cabinet,
place it in the antistatic protective bag.
External wiring connections for reverse-acting controls are identical
to those for direct-acting controls.
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Regulatory Compliance
European Compliance for CE Marking:
These listings are limited only to those units bearing the CE Marking:
EMC Directive: Declared to Directive 2014/30/EU of the European Parliament and of the
Council of 26 February 2014 on the harmonization of the laws of the Member
States relating to electromagnetic compatibility (EMC).
These listings are limited only to those L-Series ITB Control units (not mixers) bearing the ATEX markings
as well as the CE Mark (8404-7226, 8404-7227 only):
ATEX Directive:
Directive 2014/34/EU of the European Parliament and of the
Council of 26 February 2014 on the harmonization of the
laws of the Member States relating to equipment and
protective systems intended for use in potentially explosive
atmospheres
Zone 2, Category 3, Group II G, Ex nA IIC T3 Gc X
–40 °C Tamb +105 °C, IP56
Special Condition for Safe Use: The installer of the L-Series must take responsibility for meeting Clause
26.4.2 of EN60079-0 (Ed. 6 or 7) regarding impact testing. The actuator by itself does not meet this
requirement and therefore must be sufficiently protected when installed. See Chapter 2, Mechanical
Installation, for more details.
Other European and International Compliance:
Compliance with the following European Directives or standards does not qualify this product for
application of the CE Marking:
Machinery
Directive:
Compliant as partly completed machinery with Directive 2006/42/EC
of the European Parliament and the Council of 17 May 2006 on
machinery.
Pressure
Equipment
Directive:
Exempt per Article 1.2(j) of 2014/68/EU where pressure is not a
significant design factor
Restriction of
Hazardous
Substances
(RoHS):
Declared to 2011/65/EC COUNCIL DIRECTIVE of the European
Parliament and of the Council of 8 June 2011 on the restriction of the
use of certain hazardous substances in electrical and electronic
equipment.
Exemption in use: 6(a), 6(c), 7(a), 7(c)-I
North American Compliance:
These listings are limited only to those units bearing the CSA identification
CSA: CSA Certified for Class I, Division 2, Groups A, B, C, & D, T3C at 105 °C
Ambient for use in Canada and the United States.
Certificate 1380416
This product is certified as a component for use in other equipment. The final
combination is subject to acceptance by the authority having jurisdiction.
Wiring must be in accordance with North American Class I, Division 2 or European Zone 2, Category 3
wiring methods as applicable, and in accordance with the authority having jurisdiction.
Field wiring must be suitable for at least 105 °C.
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Connect ground terminal to earth ground.
The actuator should be protected from exposure to sunlight and rain.
EXPLOSION HAZARD—Do not connect or disconnect while circuit is
live unless area is known to be non-hazardous.
Substitution of components may impair suitability for Class I,
Division 2 or Zone 2 applications.
Do not clean equipment unless power has been switched off or the
area is known to be non-hazardous.
RISQUE D’EXPLOSION—N’effectuez aucune connexion ou
déconnexion tandis que le circuit est sous tension, sauf s’il
s’est avéré que la zone n’est pas dangereuse.
Le remplacement de composants peut rendre ce matériel
inacceptable pour les emplacements de Classe I, Division 2
ou Zone 2.
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Chapter 1.
General Information
Purpose and Scope
The purpose of this manual is to provide OEMs with the necessary background information for applying
the L-Series ITB and LC-50 control to gas/gasoline reciprocating engines. Topics covered include
mechanical installation and setup and troubleshooting. For application setup, please refer to manual
35154 (Position Control), manual 35141 (L-Series Speed Control), or manual 35153 (L-Series Process
Control). While the ITB/LC-50 manual is primarily targeted at OEM customers, OEMs themselves may
find it useful to copy some of the information from this manual into their application user manuals.
Intended Applications
The L-Series ITB and LC-50 controls are designed primarily for various industrial applications, including
generator sets, welders, portable refrigeration units, irrigation pumps, chipper shredders, and mobile
industrial gas or gasoline reciprocating engines. Key environmental characteristics of these applications
include industrial operating temperatures (–40 to +105 °C/–40 to +221 °F).
Use of an independent device for positive shutdown, such as a fuel
shutoff valve, is highly recommended. Failure to comply with this
recommendation can cause personal injury and/or property damage.
Use of a predicted min-fuel-shutdown procedure is highly
recommended. Failure to comply with this recommendation can
cause personal injury and/or property damage.
Automotive
Applications
On- and Off-Highway Mobile Applications: Unless Woodward's
control functions as the supervisory control, customer should install
a system totally independent of the prime mover control system that
monitors for supervisory control of engine (and takes appropriate
action if supervisory control is lost) to protect against loss of engine
control with possible personal injury, loss of life, or property
damage.
L-Series Description
The L-Series ITB and LC-50 provide a building block approach to total engine management. The modular
design consist of a die-cast aluminum throttle body, a mixer, and a fully programmable integrated digital
speed, position or process control, and bi-directional actuator. The L-Series ITB incorporates the
Woodward L-Series control with a throttle plate. The LC-50 adds a venturi-style annular ring mixer to the
L-Series ITB.
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Determining Proper Valve Size
The proper valve size can be determined using the equation below. The required Cv (Flow Coefficient)
should be calculated for both the minimum and maximum flows expected on the application. This design
allows for 80 degrees of throttle plate rotation.
Using the graph and table below, select the closest valve that has a Cv equal to or greater than the
maximum flow value at approximately 80% opening (64 degrees) to ensure reasonable flow margin. Also,
check that the particular valve’s minimum Cv listed below is less than the minimum calculated Cv for good
low idle performance.
21 *1*)460( 1
00976.0* PP SgPT
P
Q
Cv 


Where:
Cv = Flow Coefficient
Q = Mass Flow (PPH [pounds/hour] (1 pound = 0.45 kg)
Sg = Specific Gravity of Gas (use 1.0 for air)
T1 = Upstream Gas Temperature (°F) (°F = 1.8* °C + 32)
P1 = Inlet Pressure (psia) (1 psi = 6.895 kPa = .06895 bar)
P2 = Downstream Pressure (psia)
NOTE: P2 must be greater than 0.528*P1 or flow becomes choked. If P2 less than 0.528*P1, then
use P2=.528*P1
Table 1-1. Cv (Flow Coefficient)
Plate Angle
25 mm
30 mm
36 mm
43 mm
50 mm
0
0.56
0.71
0.74
0.97
1.06
5
0.59
0.93
1.13
1.48
1.85
10
0.63
1.33
1.71
2.66
3.18
20
0.98
2.84
4.10
6.23
8.31
30
1.89
5.53
8.24
12.15
16.99
40
3.54
9.57
14.53
21.24
29.48
50
6.02
15.41
23.96
35.83
49.51
60
9.48
23.55
38.27
56.93
78.80
70
14.37
33.39
59.26
88.25
127.75
80
20.03
41.18
82.45
119.95
171.32
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Figure 1-1. Cv vs Angle for L-Series ITBs
The proper valve size can be determined using the equation below. The required Cv (Flow Coefficient)
should be calculated for both the minimum and maximum flows expected on the application. This design
allows for 60 degrees of throttle plate rotation.
Table 1-2. 16 mm Trim Valve Position vs CV Value
16 mm
Pos (%)
Cv
100
9.19
95
8.85
90
8.15
85
7.35
80
6.43
75
5.56
70
4.75
65
4.04
60
3.42
55
2.86
50
2.37
45
1.92
40
1.56
35
1.26
30
1.02
25
0.86
20
0.76
15
0.73
10
0.73
5
0.73
2.5
0.72
0
0.72
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Figure 1-2. Cv vs Angle for L-Series Trim Valves
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Chapter 2.
Application Overview
Hardware Configuration Application Process
The first step in configuring a new system is to choose the appropriate hardware for the application. An
ITB, a mixer, and a version of the actuator must be selected. The ITBs and mixers come in five different
sizes.
For both the L-Series ITB and LC-50, the user must choose the appropriately sized ITB for the
application. The chart below illustrates how to choose the proper size. The intersection of the operating
rpm and the engine displacement will fall within a specific ITB band. For example, a 4.0 L engine that will
run at 2000 rpm would need a 43 mm ITB, as that point falls between the two lines for the 43 mm (square
marker lines).
If the application will have multiple speed set points, some judgment needs to be used to appropriately
size the throttle. In general, the highest speed where the engine will spend any significant percentage of
its time, or the highest speed where efficiency (or power) is important, should be used for sizing.
Figure 2-1. Application Matrix
Application Matrix for LC50 ITB
For NA and Turbo Engines at Rated Conditions
Assum es: 4-Stroke Cycle, 90% VE, 50°C Inlet Mixture Tem p, Stoichiom etric F/A Mixture, Natural Gas Fuel
600
800
1000
1200
1400
1600
1800
2000
2200
2400
2600
2800
3000
3200
3400
3600
3800
4000
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5
Engine Displacement (L)
Engine RPM
Ø 25m m ITB
Ø 30m m ITB
Ø 36m m ITB
Ø 43m m ITB
Ø 50 m m ITB
- A rea between lines for a given throttle size defines
operating range for that throttle
- V ertic al distanc e between lines defines optim um RPM
range for a fixed E ngin e Displacem ent
- Horizontal distanc e between lines defines optim um Engine
Displacem ent range at a fix ed RPM
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Manual 35144 L-Series ITB / LC-50 RoHS Compliant
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If the application is an LC-50 product, there are appropriately sized mixers for each throttle size. A
complete gaseous fuel delivery system requires:
a fixed main adjustment screw (MAS) or closed-loop trim valve
a zero-pressure regulator (ZPR)
a fuel shut-off valve
The LC-50 comes with a venturi-style mixer. By locally increasing the air speed in a pipe, the static
pressure at the location of the restriction will be lower than the pressure before this restriction. When a
number of orifices are made in the circumference of the venturi, the medium to be mixed (natural gas) will
be drawn into the venturi throat. If the pressure of the gas is kept equal to the pressure before the venturi,
the gas will be mixed with the air in a constant ratio. The pressure is kept equal to the air pressure directly
before the mixer by means of a zero pressure regulator and a compensation line. The venturi mixer is
maintenance free.
A main adjustment screw (MAS) is provided to adjust the full-power air/fuel ratio by means of an
adjustable restriction in the fuel line between the zero pressure regulator and the venturi mixer. For more
advance A/F ratio control, an L-Series O2sensing A/F ratio trim valve is available separately as a
replacement for the MAS. The LC-50 Mixer fuel inlet connection is designed to match the L-Series trim
valve bolt pattern. For more information, refer to product specification 03255.
The compensation line ensures that the gas pressure is kept equal to the air pressure before the venturi
mixer. When no compensation line is used, the outlet pressure of the ZPR will not be balanced as the air
filter becomes dirty. As the air filter gets dirty, there is an increased pressure drop after the air filter, and
the air/fuel ratio will become richer.
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Chapter 3.
Installation
When included with an ITB, the actuator depends solely on the return
spring inside the throttle body assembly to drive toward minimum fuel
when not powered. Therefore other positive shutdown devices like fuel
shut-off solenoids are recommended to ensure shutdown on loss of
signal to the control system. Also, separate overspeed trip devices are
always mandatory.
External fire protection is not provided in the scope of this product. It
is the responsibility of the user to satisfy any applicable
requirements for their system.
The installer of the L-Series must take responsibility for meeting
Clause 26.4.2 of EN60079-0 (Ed. 6 or 7) regarding impact testing. The
actuator by itself does not meet this requirement and therefore must
be sufficiently protected when installed.
Wiring must be in accordance with North American Class I, Division
2 or European Zone 2, Category 3 wiring methods as applicable, and
in accordance with the authority having jurisdiction.
Field wiring must be suitable for at least 105 °C.
Connect ground terminal to earth ground.
The L-Series is used on prime movers that typically have a high
noise level. Always use appropriate hearing protection while working
around the L-Series.
The surface of this product can become hot enough or cold enough
to be a hazard. Use protective gear for product handling in these
circumstances. Temperature ratings are included in the specification
section of this manual.
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EXPLOSION HAZARD—Do not connect or disconnect while circuit is
live unless area is known to be non-hazardous.
Substitution of components may impair suitability for Class I,
Division 2 or Zone 2 applications.
Do not clean equipment unless power has been switched off or the
area is known to be non-hazardous.
RISQUE D’EXPLOSION—N’effectuez aucune connexion ou
déconnexion tandis que le circuit est sous tension, sauf s’il
s’est avéré que la zone n’est pas dangereuse.
Le remplacement de composants peut rendre ce matériel
inacceptable pour les emplacements de Classe I, Division 2
ou Zone 2.
Mechanical Installation
Locate the L-Series control a distance from sources of extreme radiant heat, such as exhaust manifolds
or turbochargers. The operating temperature range of the control is –40 to +105 °C (–40 to +221 °F). In
spark-ignited applications, make sure the control is located away from the ignition coil, and that harness
wires are not routed next to the spark plug wires.
While it is not a requirement, it is good practice to orient the connector feature on the control in a
horizontal or downward orientation to minimize fluid accumulation between the enclosure and the mating
connector’s gasket.
For ATEX Hazardous Location applications, the installer of the L-
series ITB Control must ensure that the mounting screws provide
sufficient grounding for the ITB.
The 25, 30, and 36 mm throttles mount with 5 mm fasteners in a 43 mm square bolt pattern. The 43 and
50 mm throttles use 6 mm mounting screws in a 57 mm square pattern.
The actuator should be protected from exposure to sunlight and rain.
The L-Series ITB valve output shaft represents a pinch hazard with
the power connected. To prevent bodily harm or injury, keep all
hands, fingers, etc. away from the valve element at all times when
electrically connected.
The L-Series ITB should be used in a well-ventilated area. A methane
detector should be used if the valve will be used in an enclosed
installation.
Secondary retention of the bolts should be utilized. Consult the OEM
regarding retention methods.
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Manual 35144 L-Series ITB / LC-50 RoHS Compliant
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The L-Series ITB is not intended to support the inlet or outlet piping.
A suitable bracket must be constructed to support the valve and
piping separately to prevent damage to the throttle body.
Know in advance how to safely shut off the engine during normal
and emergency stop conditions. Shutting off power to the governor
does not always guarantee a controlled shutdown; it depends on the
final application. Safety needs to be the overriding thought during
this procedure.
The control will only meet ingress protection specifications while the
Deutsch connector is installed in the unit. The unit should not be
exposed to operating environments unless the mating connector is
installed. In addition, if a wire is not used for each of the 12 pins on
the control, a Deutsch 114017 plug must be used in place of each
missing wire. Failure to adhere to these guidelines may result in
product failure or decreased life.
See Manual 35141, 35147, or 35153 as appropriate for electrical and
software installation, application, troubleshooting, and safety
information.
The L-Series actuator output shaft is integral to the unit’s accuracy
and performance. Take special care to prevent damage to the output
shaft or ITB bore. Do not use a sharp or metallic object to open the
ITB.
Mounting gaskets are not included with the Integrated Throttle Bodies (ITB), but these can be ordered
separately as needed. For the 25, 30, and 36 mm ITBs, order gasket part number 0014-00-034. For the
43 and 50 mm ITBs, order gasket part number 0108-00-021.
The L-Series actuator has a rotation of 0–60 degrees. To get full blade rotation on the ITB, a mechanical
linkage exists inside the ITB that converts 0 to 60 degrees actuator rotation to 3 to 85 degrees blade
position. In addition, the ITB incorporates the use of an internal return spring. The spring load drives the
throttle plate to the closed position with the clocking outlined in the figure below.
Figure 3-1. Spring-Loaded Throttle Plate
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Manual 35144 L-Series ITB / LC-50 RoHS Compliant
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The LC-50 mixer can be mounted in any of three orientations of the ITB to allow convenient fuel system
connections. The L-Series ITB and LC-50 are intended to be used with gaseous fuels from low quality
pipeline natural gas to HD-5 LPG. The quality of this range of fuel varies from a lower heating value of
850 BTU/SCF (34.0 MJ/m³) to 2325 BTU/SCF (93.0 MJ/m³), and the specific gravity varies from 0.55 to
1.56 relative to air. When using a Woodward supplied ZPR, fuel pressure should be 0.25 psi (7” water
column) (1.7 kPa [178 mm water column]) to 1 psi (28” water column) (6.9 kPa [711 mm water column]).
Pressure supply range is 4–14” water for the R500Z, and 4–28” water for the R600Z.
The LC-50 mixer has two inlet sizes for air filter attachment. The smaller throttles (25, 30, and 36 mm)
have a 2.0-inch (50.8 mm) inlet. The larger throttles (43 and 50 mm) have a 2.5 inch (63.5 mm) inlet.
It is recommended that all components of the gas system, such as air filter, main adjustment screw, and
throttle valve, be installed in a symmetric way to minimize the possibility of unequal mixture distribution.
Curved pipes should not be installed closer to the venturi than 3D (where D is the diameter of the venturi
at the air inlet side).
Woodward recommends that you install a compensation line between the ZPR and the air inlet to
maintain consistent air/fuel ratio throughout the life of the system. If a compensation line is not installed,
the air/fuel ratio will be affected by the changing restriction of the air cleaner as it accumulates dirt.
If the Maxitrol ZPR is obtained from Woodward (part numbers 0055-55-062 for the R500Z [1/2" bore],
0055-00-063 for the R600Z [3/4" bore]), the following installation instructions apply. If another brand of
ZPR is used, consult that manufacturer for installation guidelines. The ZPR should be mounted with the
spring tower up. If it is not, the weight of the diaphragm and spring can offset the pressure setting. The
ZPR should be mounted as close to the MAS as possible to prevent pressure drop across excessively
long pipe lengths. This pressure drop and associated system lag can cause stability and response issues
with the mixer air/fuel ratio control.
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Figure 3-2. L-Series ITB Outline Drawings
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Manual 35144 L-Series ITB / LC-50 RoHS Compliant
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Figure 3-3a. LC-50 Outline Drawing (small bore)
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