System Saver TWIN Air Dryer

Transcription

System Saver
TWIN Air Dryer
Maintenance Manual 35
Revised 11-02
Service Notes
This publication provides maintenance and service procedures for Meritor WABCO’s System Saver TWIN
air dryers. The information contained in this publication was current at the time of printing and is subject to
revision without notice or liability.
1.
You must understand all procedures and instructions before you begin maintenance and service
procedures.
2. You must follow your company’s maintenance and service guidelines.
3. You must use special tools, when required, to avoid serious personal injury and damage to
components.
Meritor WABCO uses the following notations to warn the user of possible safety problems and to provide
information that will prevent damage to equipment and components.
WARNING
A WARNING indicates a procedure that
you must follow exactly to avoid serious
personal injury.
CAUTION
NOTE: A NOTE indicates an operation, procedure
or instruction that is important for proper service.
A NOTE can also supply information that will
help to make service quicker and easier.
T
A CAUTION indicates a procedure that
you must follow exactly to avoid damaging
equipment or components. Serious personal
injury can also occur.
This symbol indicates that you must tighten
fasteners to a specific torque.
Visit Our Web Site
Visit the Meritor WABCO website for
additional product and service information:
meritorauto.com
Drivetrain Plus™ Technical
Electronic Library (TEL) on CD
The CD includes product and service
information on Meritor’s Drivetrain Plus™
component lineup. $20. Order TP-9853.
How to Order
Call Meritor’s Customer Service Center at
800-535-5560.
Copyright 2002 Meritor WABCO
Table of Contents
Section 1: Introduction
System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
TWIN Support Documentation
How the TWIN Air Dryer Works
TWIN Air Drying Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Air Dryer Parts
Wiring Harness Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Standard Wiring Harness
Wiring/Plumbing Kit for E-Type Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Section 2: Troubleshooting and Testing
Routine Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Troubleshooting the TWIN Air Dryer System
Pressure Relief Valve
Meritor WABCO TWIN Air Dryer Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8.
System Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Heater Resistance
Leak Test
Section 3: Installing Replacement Parts
Desiccant Cartridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Left Piston Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Left Piston Assembly
Right Piston Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Right Piston Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Charging Valve Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Solenoid and Armature Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Heater Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Purge Valve Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Outlet Check Valve Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Orifice Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Purge Silencer (Muffler) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Air Dryer Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Appendix I: Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-A
Appendix II: Application Information
General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-A
Operating Environment Requirements
Installation Instructions for Special Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-A
Bulk-Unloading or Central Tire Inflation (CTI) Air Systems
Installing a Back-Pressure Control Valve
Holset E-Type Compressor Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-A
Function
Econ Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-A
Econ Valve Operation
Replacing the Econ and Check Valves on a Holset E-Type Compressor System
Replacing the Solenoid Valve
Installing a Turbo Cutoff Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-A
Installation Instructions
Vehicle Air System E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-A
Quick-Reference Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . inside back cover
Notes
Section 1
Introduction
System Overview
Section 1Introduction
This maintenance manual provides an overview of
the Meritor WABCO System Saver TWIN Air Dryer.
A typical Meritor WABCO System Saver TWIN
installation is illustrated below. Figure 1.1.
If you are servicing a Meritor WABCO System
Saver Series Single Air Dryer, use Maintenance
Manual 34.
Figure 1.1
GOVERNOR
COMPRESSOR
INTAKE LINE
UNLOADER
PORT
RESERVOIR
TO GOVERNOR
LINE
SYSTEM SAVER TWIN
AIR DRYER
DRYER
OUTLET
PORT
COMPRESSOR
COMPRESSOR
DISCHARGE
LINE
TO BRAKE
SYSTEM
CHECK
VALVE
CONTROL
(PURGE)
PORT
SYSTEM
RESERVOIR
DRYER
INLET
PORT
SYSTEM
RESERVOIR
SUPPLY
TANK
CHECK
VALVE
1002211c
TWIN Support Documentation
TP-94104, Installing the Meritor WABCO System
Saver TWIN Air Dryer, provides complete
installation instructions for the TWIN Air Dryer.
TP-94104 is shipped with all TWIN dryers. For
additional copies, contact Meritor Customer
Service at 800-535-5560.
PB-96135 contains a complete listing of System
Saver TWIN replacement parts.
TP-9773 is a poster-size troubleshooting guide. It
also illustrates the various components that make
up the System Saver TWIN air dryer. TP-97100 is a
pocket-size version of TP-9773.
TP-9672, Air Dryer Application Guide, provides an
in-depth look at System Saver TWIN air dryer
applications.
Revised 11-02
T-97106V ($20.00) is a 30-minute videotape
covering application, maintenance and service
information for System Saver TWIN air dryers.
Literature and videos are available on our web site
(meritorwabco.com) or call the ArvinMeritor
Customer Service Center (800-535-5560) to order.
How the TWIN Air Dryer Works
TWIN air dryer cartridges contain desiccant
material that filters and dries compressed air. The
process begins when supply tank pressure drops
below cut-in pressure (approximately 100 psi).
When this happens, the governor turns the
compressor on. The compressor sends air to the
supply port of the dryer, and an air drying cycle
begins.
MM-35
Page 1
Section 1
Introduction
TWIN Air Drying Cycle
Figure 1.2
Figure 1.4
1002212b
1002214b
1
2
Dryer Inlet
Dryer Outlet
3
4
Governor Port
Purge Valve
Air drying cycle begins
Air enters the dryer at the supply port (Port 1)
O Air flows past piston in to the first (right) cartridge.
O Air flows through cartridge where it is dried;
moisture and contaminants are filtered out through
the desiccant material in the cartridge.
O Dry, clean air flows to the delivery port (Port 2) of
the dryer for delivery to the supply tank.
— Some air is diverted to the second cartridge
where it moves upward through the desiccant.
This cleans and dries (regenerates) the
desiccant.
While the compressor is running, a mild flow of air
will vent to atmosphere through the purge valve.
1
2
Dryer Inlet
Dryer Outlet
3
4
Governor Port
Purge Valve
Air drying cycle continues,
cartridge functions reversed
O Incoming air enters the second (left) cartridge for
drying and then flows to the delivery port.
O Small amount of dried air flows into the first (right)
cartridge to regenerate desiccant.
O Alternating air drying cycles continue, one cartridge
to the other, every 60 seconds as long as the
compressor is running.
Figure 1.5
Figure 1.3
2
1
3
1002213b
4
1
2
Dryer Inlet
Dryer Outlet
1002215b
3
4
1002213b
Governor Port
Purge Valve
1
2
Dryer Inlet
Dryer Outlet
3
4
Governor Port
Purge Valve
Dryer purges
O Switching is controlled by timer/solenoid.
O Pistons shift from right to left, reversing airflow
pattern.
O Supply tank reaches cutout pressure. Governor
unloads compressor.
O Governor supplies air to unloader port (Port 4) of
dryer.
O Moisture and contaminants pass through purge
valve and out of dryer.
A mild purge, or puff of air, can be heard at the
purge valve at the time of shift.
A burst of air occurs when dryer purges; airflow from
purge valve ceases for duration of unloaded cycle.
At 60 psi or greater, the air dryer
switches cartridges every 60 seconds
MM-35
Page 2
Revised 11-02
Section 1
Introduction
System Components
Air Dryer Parts
Figure 1.6
Air Dryer Base: The aluminum casting to which
all air dryer components are assembled. Base
contains threaded mounting holes. Refer to
Figure 1.6.
1002216a
Figure 1.7
Desiccant Cartridge: A cylindrical steel housing
that contains the filter element and desiccant
necessary to filter and dry the air that passes
through it. For easy maintenance, all Meritor
WABCO air dryer cartridges are of spin-on/spin-off
design. Refer to Figure 1.7.
1002217a
Figure 1.8
Heater Assembly: Located in the air dryer base, the
heater keeps the water that collects in the air dryer
from freezing. The assembly consists of a
cylindrical resistive-type heating element and a
small circular thermostat. The thermostat turns the
heater on at 45°F (7°C) and turns it off at 86°F
(30°C). Refer to Figure 1.8.
1002218a
Figure 1.9
Orifice and Check Valve Assembly: Controls the
flow of air for regeneration. There are three sizes:
0.8 mm for systems with compressor ratings less
than 21 CFM, 1.0 mm for compressor ratings
between 21 and 35 CFM, and 1.3 mm for
compressor ratings greater than 35 CFM.
Refer to Figure 1.9.
1002219a
Revised 11-02
MM-35
Page 3
Section 1
Introduction
Air Dryer Parts, Continued
Figure 1.10
Charging Valve: Keeps control valves from
shuttling while the system is filling and pressure
is too low to ensure proper operation. Refer to
Figure 1.10.
100220a
Figure 1.11
Outlet Check Valve: Prevents air from flowing back
through the air dryer and escaping out the purge
valve during the compressor unload cycle, or while
the vehicle is shut off. It is located in the outlet port
of the air dryer. Refer to Figure 1.11.
100221a
Figure 1.12
Purge Valve: Allows collected moisture and
contaminants to be expelled from the air dryer
during the unloaded cycle. The purge valve
remains open for the entire compressor unload
cycle. Refer to Figure 1.12.
NOTE: While the compressor is running, a mild
flow of air will vent to atmosphere through the
purge valve. This is a normal condition.
100222a
Figure 1.13
Solenoid and Armature Assembly: Controls timing
and operation of right and left piston assemblies.
This determines which cartridge dries and which
one regenerates. Refer to Figure 1.13.
100223a
MM-35
Page 4
Revised 11-02
Section 1
Introduction
Air Dryer Parts, Continued
Figure 1.14
Pressure Relief Valve: Protects the dryer from
over-pressurization. May be installed using a
street-T fitting, shown in Figure 1.14, or directly
into the dryer casting on dryers with the
appropriate port (Port 31). Refer to Figure 2.2.
100225a
Figure 1.15
Piston Assemblies (Left and Right): Control
air-flow direction between TWIN cartridges. Both
piston assemblies have their own covers. Refer
to Figure 1.15.
1
2
Left Piston Kit
Left Piston Cover Kit
3
4
Right Piston Kit
Right Piston Cover Kit
Figure 1.16
Purge Silencer: Optional equipment. Used to
reduce the noise level of dryer purge. Refer to
Figure 1.16.
100227a
Wiring Harness Options
Two types of power harnesses are used with the TWIN; the Standard Wiring Harness and the E-Type Wiring
Harness. The wiring harness is included with the original installation. For part numbers and other ordering
information, refer to PB-96135, the TWIN parts book.
Standard Wiring Harness
Figure 1.17
The TWIN uses a standard two-circuit power
harness for heater and timer/solenoid in most
applications (standard compressors). Refer to
Figure 1.17.
100224a
Revised 11-02
MM-35
Page 5
Section 1
Introduction
Wiring Harness Options, Continued
Wiring/Plumbing Kit for E-Type Compressor
Figure 1.18
A three-circuit power harness must be used with
Holset E-Type compressors. An Econ valve and
check valve assembly, as well as a special solenoid
valve, are also required. Refer to Figure 1.18.
1.
Three-circuit power harness
2. Econ valve
3. Solenoid valve
1002228b
4. Check valve assembly
An exploded view of the TWIN air dryer components appears in Figure 1.19.
Figure 1.19
1002229b
1
2
3
4
5
6
7
8
MM-35
Page 6
Left Piston Kit
Orifice Kit
Desiccant Cartridge
AIR DRYER BASE
Right Piston Kit
Right Piston Cover Kit
Solenoid & Armature Parts (3 Kits)
Charging Valve Kit
9
10
11
12
13
14
15
Purge Valve Kit
Outlet Check Valve Kit
Heater Kit
Left Piston Cover Kit
Manufacturing Location Code
Part Number
Date Code — First 2 Digits = Build Week/Last 2 Digits = Build Year
Revised 11-02
Section 2
Troubleshooting and Testing
Routine Maintenance
Section 2Troubleshooting and Testing
To keep your Meritor WABCO System Saver TWIN operating efficiently, the following routine maintenance
is recommended:
Interval
Required Action
Weekly.
Check the exhaust from the air dryer.
Weekly, or as recommended by the vehicle OEM,
whichever is most frequent.
Check for moisture in the system by draining the
supply tank.
O Every 2-3 years — or more often depending on
usage, vocation and condition of compressor.
O Whenever compressor is rebuilt.
Replace the desiccant cartridge with new
cartridges.
Troubleshooting the TWIN Air Dryer System
WARNING
To prevent serious eye injury, always wear safe eye protection when you perform vehicle maintenance
or service.
Engage the parking brake to prevent the vehicle from moving before you begin maintenance or service
procedures that require you to be under the vehicle. Serious personal injury can result.
Park the vehicle on a level surface. Block the wheels to prevent the vehicle from moving. Serious personal
injury can result.
Remove all air from the air system before servicing any component in the air system. Pressurized air can
cause serious personal injury.
Check the build date on the part identification tag to determine whether or not it has an integral pressure
relief valve. Refer to Figure 2.1. If the build date is 11/96, or higher, it has an integral pressure relief valve
which can be seen at the back of the dryer. Refer to Figure 2.2. Dryers without integral relief valves must use
a pressure relief valve and street Tee fitting.
Figure 2.2
Figure 2.1
1002230b
1
2
ID Tag
Pressure Relief Valve Assembly
Revised 11-02
1002231a
1
MM-35
Page 7
Section 2
Meritor WABCO TWIN Air Dryer Troubleshooting Guide
Condition
Possible Cause
Suggested Repair
Air dryer does not work
properly.
Air dryer mounted too close to heat
source, such as engine exhaust stack
or muffler.
Verify proper installation.
Air delivered to air dryer exceeds
175°F (79°C).
Extend length of compressor
discharge line as required, or install
cooling coil.
Lines blocked with dirt.
Clear or replace lines.
Loose fittings.
Tighten or seal fittings.
Air dryer not switching every 50 to
60 seconds during compressor
loaded cycle.
Verify solenoid operating properly.
Desiccant saturated.
Check timer (solenoid) and make
necessary repairs.
Water in air system
NOTE: If timer is working properly
but dryer does not switch, check for
sludge on valves. Clean the dryer.
If condition is not corrected:
Check pistons and make necessary
repairs.
Replace desiccant cartridge(s).
Dryer leaks heavily from
purge valve every other
60-second timer cycle.
Improper air pressure maintained at
dryer; 35-75 psi allows partial
switching but does not seal valves
for a second cycle.
Install back-pressure control valve in
system between outlet of dryer and
source of air take-off.
Dryer frozen (water in air
dryer is freezing).
Problem with heater assembly.
Replace heater assembly.
Power supply to heater interrupted or
short-circuited.
Repair or replace power supply
circuit. Replace fuse if needed.
Low voltage to heater unit.
Ensure voltage is at least 10.5 volts
(12-volt system) or 20 volts (24-volt
system).
Wrong voltage air dryer used
(e.g., 24-volt in 12-volt system).
Replace with proper air dryer.
Problem with air compressor.
Repair or replace compressor.
Excessive amount of oil
released from exhaust of
air dryer.
or
Sludge build-up on air
dryer base.
MM-35
Page 8
Replace desiccant cartridge(s).
Worn turbocharger oil seals
(turbocharged compressors only.)
Repair or replace turbocharger.
Revised 11-02
Section 2
Condition
Possible Cause
Suggested Repair
Dryer does not purge
when compressor
unloads.
Wrong air line or no air line
connected to dryer Port 4.
Connect air lines properly.
Control line from governor unloader
port to air dryer leaking.
Repair any leaks.
Purge valve stuck closed.
Replace purge valve.
Problem with governor.
Repair or replace governor.
Cutout pressure never reached by air
compressor.
Check air system for leaks.
If condition is not corrected:
Check/repair compressor.
Air pressure does not
build in brake system.
Leak in air system.
T ighten all air line connections, test
system for leaks, make necessary
repairs.
Problem with compressor.
Repair or replace the compressor.
Repair or replace problem air system
components.
Air continues to flow
from purge valve after air
compressor unloads.
Air dryer control port (Port 4)
plumbed wrong.
Verify proper installation.
Obstruction in air compressor
discharge line or air dryer outlet line.
Check lines for crimps or blockages.
Make necessary repairs.
Air compressor discharge line
plumbed to air dryer outlet port
(Port 2).
Verify proper installation. Make
necessary repairs.
CTI Applications: Back-pressure
control valve installed incorrectly.
Verify installation of back-pressure
control valve.
Faulty compressor discharge hose.
Check for pinhole leaks along length
of compressor discharge line from
compressor to air dryer. If found,
replace hose. Make sure replacement
hose is capable of sustained high
temperature use.
Compressor intake is turbocharged
and there is no turbo cutoff valve in
system.
Install a turbo cutoff valve.
Orifice blocked, internal passages
blocked, valve components covered
with sludge.
Clean as needed, replace worn parts.
O-rings in bad condition (cut, worn).
Make sure O-rings are properly
installed and in good condition.
NOTE: This could be
accompanied by a loss of
engine power.
Internal valves not
switching.
Revised 11-02
MM-35
Page 9
Section 2
System Tests
Solenoid Check
Heater Resistance
Turn ignition on. Do not start engine.
To ensure power to solenoid, check at cable
with volt-ohmmeter, or test light. Refer to
Figure 2.4.
Figure 2.3
Go to TWIN dryer and listen for the solenoid
to click. There should be one click every
50-60 seconds. If not, solenoid is defective.
Figure 2.4
1
Heater
3
2
To avoid damaging components, Meritor WABCO
recommends performing this resistance check with
the heater in place.
1. Set volt-ohmmeter to ohms.
2. With wires connected and properly secured,
attach one probe to the heater connector and
the second to the lead on the thermostat. Refer
to Figure 2.3.
3. Measure the resistance.
12-volt system: If 1.0–2.0 ohms, resistance is
acceptable.
If the resistance is less than 1.0 ohm or more
than 2.0 ohms, replace heater.
24-volt system: If 5.0–7.0 ohms, resistance is
acceptable.
If the resistance is less than 5.0 ohms or more
than 7.0 ohms, replace heater.
4. Reinstall components and vehicle harness.
Leak Test
1. Drain the air from all system tanks.
2. Close the draincocks on all reservoirs.
3. Start the vehicle. Allow the air system pressure
to build while the engine idles.
4. There will be a light airflow from the purge
valve. This is normal and will continue until the
air compressor unloads.
After 50–60 seconds, and if the system pressure
has built to at least 60 psi, there will be a mild
purge, or exhaust of air, as the dryer switches
cartridges. If there is no purge, the solenoid may
be bad. Refer to “Solenoid Check” box for a
quick solenoid test.
When the air system reaches cutout pressure,
the dryer will purge completely. After purging,
the dryer will not exhaust any air until the
compressor starts up again.
MM-35
Page 10
4
5
6
1
1
2
3
Standard Harness
P/N R950041
Ground (–)
Locating Pin
1003340a
4
5
6
Positive (+)
Timer/Solenoid
Heater
5. Shut off the engine.
6. Apply a soap solution to each connection that
contains pressurized air. Check the connections
to see if soap solution bubbles.
No soap
bubbles
Soap bubbles
appear.
Connections are sealed
properly.
Connections not sealed
properly. To repair:
1. Drain all reservoirs.
2. Remove leaking
connection.
3. Inspect the connectors and
ports for damaged threads
or cracks. Replace if
necessary.
4. Apply pipe sealant or
Teflon tape to connection.
Repeat leak test until all connections are sealed.
Revised 11-02
Section 3
Installing Replacement Parts
Section 3Installing Replacement Parts
WARNING
or service.
Remove all pressure from the air system before you disconnect any component including the desiccant
cartridge. Pressurized air can cause serious personal injury.
Park the vehicle on a level surface. Block the wheels to prevent the vehicle from moving. Serious personal
injury can result.
A Component Replacement Guide appears on the inside back cover.
Desiccant Cartridge
NOTE: You may replace one or both TWIN cartridges.
Figure 3.1
1.
Replacement kit contains one cartridge and
one O-ring. Refer to Figure 3.1.
2. Loosen and remove the old cartridge. Use
strap wrench if necessary.
3. Remove and discard O-ring from dryer base.
1002234a
Figure 3.2
4. Inspect and clean seal seats. Repair any
damage.
NOTE: If seats are damaged so badly that a tight
seal cannot be maintained, replace the air dryer.
5. Lubricate and install new O-ring on stem.
6. Thread replacement cartridge onto the base
until the seal touches the base. Then, tighten
the cartridge one-half (½) additional turn.
Do Not Overtighten. Refer to Figure 3.2.
1002235a
1
2
3
O-Ring
Seal Seat
Seal
Revised 11-02
MM-35
Page 11
Section 3
Left Piston Cover
Figure 3.3
1.
Remove the old cover. Use a 5 mm Allen
wrench to loosen the mounting bolts. Remove
bolts. Lift cover off of dryer. Refer to Figure 3.3.
NOTE: If you are replacing the left piston
assembly, refer to the following instructions.
2. If you are replacing the cover only:
The two small O-rings that fit in the air
passages and the two large O-rings that fit in
the grooves in the outer diameter of the
cover guide are not included in the cover
replacement kit. Remove these O-rings
from the old cover, clean, apply Meritor
WABCO-recommended lubricant, and install
them in the new cover.
1002236a
1
2
3
Remove
Install
77-85 in-lbs (8.5-9.5 N•m)
T
3. Install the replacement cover. T ighten bolts to
77–85 inch-pounds (8.5–9.5 N•m). T
O-rings not included in cover replacement kit.
Left Piston Assembly
Figure 3.4
1.
Review Figure 3.4 to make sure you have all of
the parts required to replace the left piston
assembly. Use the grease included with the
replacement kit to lubricate O-rings and seals.
2. Remove the left piston cover (refer to
instructions, above). Remove the two small
O-rings from the breather holes and the two
large O-rings from the grooves in the outer
diameter of the cover guide.
1002237a
These O-rings are installed in the cover, but are included
with the piston assembly replacement kit. They should be
replaced whenever you replace the piston assembly.
Clean the cover. Save cover and mounting
bolts for reassembly.
Seals, O-rings and springs are included in a separate replacement kit
from the hard parts (piston, spool and lip seal). Refer to PB-96135, the
TWIN Parts Book.
MM-35
Page 12
Revised 11-02
Section 3
Left Piston Assembly, Continued
Figure 3.5
3. Remove the left piston and spring assembly
from the piston bore.
Inspect and clean the bore area. Refer to
Figure 3.5.
1002238a
Figure 3.6
4. Lubricate and install the large replacement
O-ring in groove on head of piston guide. Refer
to Figure 3.6.
1002239a
5. If O-rings and spool are already installed on
the piston, lubricate the rubber parts, then go
to Step 6. If not:
Figure 3.7
a. Install lubricated O-ring in first groove of
piston guide.
b. Use snap ring pliers to install snap ring in
snap ring groove on shaft of piston.
c.
1002240a
Install lubricated lip seal in groove of spool.
Insert spool with lip seal onto piston. Lip of
seal must face away from the dryer.
d. Install lubricated O-ring in groove on
piston shaft.
Lip of seal must face away from dryer.
e. Use snap ring pliers to install snap ring in
snap ring groove under spool.
f.
6. Install the two large, lubricated O-rings in the
grooves in the outer diameter of the cover
guide. Install the small lubricated O-ring in the
breather hole on the cover. Refer to Figure 3.3.
Figure 3.8
7.
1002241a
Revised 11-02
Install lubricated O-ring in groove on
piston shaft. Refer to Figure 3.7.
Install spring in left piston cover. Insert piston
assembly into left piston cover. Stem of piston
will face away from dryer. Refer to Figure 3.8.
8. Replace the left piston cover. (Refer to
instructions under “Left Piston Cover.”)
MM-35
Page 13
Section 3
Right Piston Cover
Figure 3.9
The right piston cover replacement kit contains
only the cover. When you remove the old cover,
retain the mounting bolts for reassembly. Also,
remove and save the two small, air passage
O-rings. Refer to Figure 3.9.
The right piston cover houses the solenoid/
armature and charging valve assemblies.
Carefully remove and save these assemblies.
Clean and inspect them before reinstalling in
the new cover. You must also remove the right
piston assembly when replacing the cover.
If you are replacing any of these assemblies,
you should follow the instructions that appear
in this manual:
O Right Piston Assembly, (in this section)
O Charging Valve Assembly, (in this section)
O Solenoid and Armature Assembly,
(in this section)
Figure 3.10
1.
Unscrew the power harness and disconnect it
from the solenoid. Remove and save the
solenoid. Refer to Figure 3.10.
2. Carefully remove the armature assembly end
cap and O-ring from the solenoid. Save these
for reassembly.
3. Use a 5 mm Allen wrench to loosen and
remove the three long piston cover bolts from
the armature plate.
Remove the armature assembly. Lift the cover
off of the dryer. Save parts for reassembly.
4. Loosen and remove the short piston cover bolt. Save bolt for reassembly.
5. Remove the right piston cover. Remove and save the two small O-rings from the cover breather holes.
MM-35
Page 14
Revised 11-02
Section 3
Right Piston Cover, Continued
Figure 3.11
6. Loosen and remove the charging valve nut —
remove carefully, this is a spring-loaded valve.
Remove the charging valve assembly from the
right piston cover. Refer to Figure 3.11.
7.
Carefully remove the right piston assembly
from the dryer cavity. This will help avoid
damage to the assembly when the new cover
is installed.
8. Clean and lubricate the two small O-rings removed from the old cover. Install them in the breather
holes in the replacement cover.
9. Replace the charging valve assembly in the right piston cover.
Figure 3.12
10. Insert the piston assembly into the piston
cover cavity. Do not damage the lip seal during
this procedure. Use the flat side of a small, flat
screwdriver to tuck the assembly into the
cover. Refer to Figure 3.12.
11. Install the cover, charging valve down, over the
piston assembly.
12. Replace the short mounting bolt. Finger tighten
only.
13. Replace solenoid and armature assembly. Refer to “Solenoid and Armature Assembly” in this section.
14. Connect the power harness to the solenoid. Make sure connection is tight.
15. Test the installation.
Revised 11-02
MM-35
Page 15
Section 3
Right Piston Assembly
Figure 3.13
1. Review Figure 3.13 to make
sure you have all of the parts
required to replace the right
piston assembly. Use the
grease provided with the
replacement kit to lubricate
O-rings.
1002246a
1
These O-rings are installed in the cover, but are included with the piston
assembly replacement kit. They should be replaced whenever you replace
the piston assembly.
Seals, O-rings and springs are a separate replacement kit from hard
parts (piston, spool and lip seal). Refer to PB-96135, TWIN Parts Book, for
additional information.
NOTE: You do not have to remove the charging valve when replacing only the right piston assembly.
1.
Disconnect the power harness. Remove the
solenoid and armature assembly. Remove the
right piston cover.
2. Remove right piston assembly. Clean piston
bore thoroughly.
3. Install large lubricated O-ring in groove on
head of piston.
4. If O-rings and spool are already installed on
the replacement piston, lubricate the rubber
parts. Then, go to Step 5. If not:
a. Use snap ring pliers to install a snap ring
into snap ring groove closest to piston
head.
5. Insert piston and spring assembly into the right
piston cover.
Remove the two small O-rings from the piston
cover. Lubricate the two new O-rings included
in the right piston assembly replacement kit
and install them in the piston cover.
6. Replace the right piston cover, armature and
spring assembly, and solenoid. For detailed
instructions:
O Right Piston Cover, (in this section)
O Solenoid and Armature Assembly,
(in this section)
b. Insert lubricated lip seal in groove of spool.
c.
Install lubricated O-ring in groove on
piston shaft.
d. Install spring over piston shaft.
e. Install spool with lip seal into piston shaft.
Lip of seal will face away from air dryer.
f.
Install snap ring in groove on piston shaft
to hold spool in place.
g. Install O-ring into groove on piston shaft.
MM-35
Page 16
Revised 11-02
Section 3
Charging Valve Assembly
Figure 3.14
NOTE: You do not have to remove the right piston
cover or solenoid when replacing the charging
valve assembly.
1.
Check Figure 3.14 to make sure you have all of
the parts needed to replace the charging valve
assembly.
Use the grease provided with the replacement
kit to lubricate the O-ring and spring.
1002247a
Figure 3.15
2. Remove dust cap from charging valve nut.
Then, loosen and remove the nut — remove
nut carefully, this is a spring-loaded valve.
Remove the old charging valve from the right
piston cover. Refer to Figure 3.15.
1002248a
3. Clean the charging valve bore and seat. Use
the grease included with the replacement kit to
lube the area.
Figure 3.16
4. Install piston and spring in cover bore. Refer to
Figure 3.16.
5. Install lubricated O-ring in bore groove of
special nut.
1002249a
6. Install washer on nut. Insert nut into cover
bore. Carefully guide piston into the bore in
the nut.
Figure 3.17
7.
Install lubricated rubber dust plug at end of
nut. Refer to Figure 3.17.
1002248a
Revised 11-02
MM-35
Page 17
Section 3
Solenoid and Armature Assembly
This assembly requires two replacement kits: Solenoid and Mounting Sleeve and Other Solenoid Parts.
You will need both kits to complete the installation. (Refer to PB-96135, the TWIN parts book.)
CAUTION
To avoid damaging the solenoid, make sure you install the proper solenoid, 12-volt or 24-volt. Solenoid
voltage is determined by the vehicle's electrical system.
NOTE: Solenoid and Armature Assembly is installed on the right piston cover.
1.
Figure 3.18
the parts needed to replace the solenoid and
armature assembly.
Use the grease included in the replacement kit
to lubricate all O-rings.
2. Remove the old solenoid and armature
assembly:
a. Disconnect power harness.
b. Lift solenoid off of cover. Refer to
Figure 3.19.
c.
1002250a
1
(2 Kits)
Remove the three piston cover mounting
bolts that hold the solenoid mounting plate
in place. Retain bolts for use in reassembly.
d. Remove breather from end of nut.
e. Unscrew nut and remove from solenoid.
f.
Figure 3.19
Remove the O-rings, one from each side,
from the solenoid.
g. Remove the armature retaining plate.
h. Remove Armature and Spring assembly.
1002251a
1
Insert O-Ring
3. Inspect and clean the solenoid bore. Do not
lube this area — apply lube to O-rings only.
Figure 3.20
4. Install lubricated O-ring in groove on solenoid
sleeve.
5. Insert the open end of the sleeve through hole
in retaining plate. Refer to Figure 3.20.
6. Insert sleeve with armature and spring into
cavity.
1002252a
MM-35
Page 18
Revised 11-02
Section 3
Solenoid and Armature Assembly, Continued
7.
Position armature retainer plate on cover, lining up holes on plate with holes in the cover.
8. Install the three long bolts through the armature retainer plate. T ighten all four bolts to 77–85 in-lbs
(8.5–9.5 N•m). T
Figure 3.21
9. Install lubricated O-ring on sleeve and position
against mounting plate.
10. Position solenoid over sleeve, writing side
facing dryer. Install lubricated O-ring in bore on
dryer side of solenoid. Refer to Figure 3.21.
11. Install lubricated O-ring over end of sleeve.
12. Install nut at end of sleeve. Screw breather
onto nut. Finger tighten.
13. Connect the power harness to the solenoid. Follow these steps to test solenoid.
O Turn ignition on. Ensure power to solenoid.
O Listen for click to sound after 50–60 seconds.
Click occurs:
Solenoid O.K.
No click:
Voltage not sufficient or solenoid damaged or improperly installed.
Heater Assembly
NOTE: Select 12- or 24-volt replacement kit, depending upon vehicle voltage.
1.
Figure 3.22
the parts needed to replace the heater
assembly.
2. Disconnect the power harness.
3. Remove the two screws holding wiring
connector in place.
1002254a
Figure 3.23
4. Remove wiring harness and O-ring to access
retainer screw. Refer to Figure 3.23.
5. Remove retainer screw.
6. Remove thermostat retainer.
1002255a
Revised 11-02
MM-35
Page 19
Section 3
Heater Assembly, Continued
Figure 3.24
7.
Remove and discard the old heater assembly.
8. Inspect and clean the heater cavity. Area must
be free of dust and oil.
9. If not assembled, attach power leads to
thermostat and wiring connector.
Insert the heater and thermostat with power
leads into the heater cavity. Refer to
Figure 3.24.
Figure 3.25
10. Install the retainer and tighten the screw that
holds the element and thermostat in place.
11. Install lubricated O-ring in base of wire
connector.
12. Gently press wire connector into place in
heater cavity. Tighten down the two mounting
screws. Refer to Figure 3.25.
13. Connect heater assembly to power harness.
1
Mounting Screws
MM-35
Page 20
Revised 11-02
Section 3
Purge Valve Assembly
Figure 3.26
1.
Review Figure 3.26 to make sure you have all
of the parts required to replace the purge valve
assembly.
Use the grease included with the replacement
kit to lubricate O-rings.
NOTE: The shim may not be included with the kit.
If it is not included, it is not required. If it is
included, install it between the spring and valve
body.
1002258a
1
Shim — Refer to Note
Figure 3.27
2. Remove old purge valve assembly from
bottom of air dryer. Refer to Figure 3.27.
O Remove snap ring, valve body and spring.
O Pull valve assembly out of dryer base.
O Remove O-ring.
3. Inspect and clean valve bore.
4. Apply a thin layer of grease to the valve bore
(use grease included in replacement kit).
5. Install lubricated O-rings: one in dryer base,
one on valve head.
6. Install spring in valve head.
1
2
3
7.
Spring
Valve Head
Valve Assembly
Insert valve body, wide end toward dryer, onto the piston shaft.
NOTE: If a shim is included in the kit, install it between the spring and valve body.
8. Install the retainer ring.
Revised 11-02
MM-35
Page 21
Section 3
Outlet Check Valve Assembly
Figure 3.28
1.
of the parts required to replace the outlet check
valve assembly.
Use grease provided with the replacement kit
to lubricate O-rings and seals.
1002260a
Figure 3.29
2. Remove the snap ring from dryer Port 2.
Then, remove the old check valve assembly.
1002261b
3. Inspect and clean valve bore. Remove any
excess debris.
Figure 3.30
4. Install lubricated O-ring in groove on
underside of check valve. Refer to Figure 3.30.
5. Install check valve in bore with shaft facing
dryer.
1002262a
Figure 3.31
6. Install perforated washer over top of spring.
7.
While holding spring and washer in place,
install snap ring in the bore groove.
1002263a
MM-35
Page 22
Revised 11-02
Section 3
Orifice Assembly
NOTE: Select 0.8 mm, 1.0 mm or 1.3 mm orifice replacement kit. Check the part number of the air dryer to
determine orifice size. (Refer to PB-96135, the TWIN parts book.)
1.
Figure 3.32
of the parts required to replace the orifice
assembly.
Use the grease included with the replacement
kit to lubricate O-rings and seals.
2. To access the orifice assembly, unscrew and
remove the desiccant cartridge from the dryer
base. Remove the O-ring. Save the cartridge
and O-ring for reassembly.
1002264a
Refer to ”Desiccant Cartridge” in this section
for information about removing the desiccant
cartridge.
Figure 3.33
3. Remove the old snap ring and orifice assembly
from the base of the dryer. Refer to Figure 3.33.
4. Inspect and clean the orifice bore.
5. Install the perforated washer in dryer bore.
1002265a
Figure 3.34
6. Install the spring on top of the perforated
washer. Refer to Figure 3.34.
7.
Install lubricated O-ring in groove on check
valve stem.
8. Insert check valve into bore with the stem
facing away from dryer.
1002266a
Revised 11-02
MM-35
Page 23
Section 3
Orifice Assembly, Continued
9. Install lubricated O-ring in groove on orifice part.
10. Install plastic orifice in bore. Carefully guide check valve into center hole. Refer to Figure 3.35.
NOTE: Molded ribs on orifice must face away from dryer.
11. Install snap ring to hold orifice assembly in place.
Figure 3.35
12. Install large lubricated O-ring over the dryer
base where cartridge screws on.
13. Install the desiccant cartridge. Refer to
”Desiccant Cartridge” in this section.
Purge Silencer (Muffler)
NOTE: This is an optional part designed to reduce dryer purge noise level.
Figure 3.36
1.
Remove snap ring. Remove old silencer from
purge valve head. Do not damage purge valve
head.
2. Clean purge valve head.
3. Insert replacement silencer into purge valve
head. Secure with snap ring. Refer to
Figure 3.36.
1
2
Purge Valve Head
Silencer
MM-35
Page 24
Revised 11-02
Section 3
Air Dryer Assembly
NOTE: This procedure is for removing and replacing a unit. For instructions on an initial installation, refer
to TP-94104, Installing a System Saver TWIN Air Dryer.
Figure 3.37
1.
Drain all pressure from the air system.
Disconnect all air lines.
Use markers to label the lines for proper
reinstallation. Refer to Figure 3.37.
2. Disconnect the heater electrical plug from the
heater receptacle and the solenoid connector
from the solenoid/timer.
1002269a
1
Drain air pressure and disconnect these air lines before
replacing the dryer.
Figure 3.38
3. Remove the air dryer mounting bolts. Remove
the air dryer from its mounting bracket. Refer
to Figure 3.38.
4. Attach the new unit to the frame or mounting
bracket with new mounting capscrews and
washers. Tighten the capscrews to 22–30 lb-ft
(30–40 N•m). Refer to Figure 3.39. T
1002270a
Figure 3.39
5. Connect heater electrical plug to heater
receptacle. Connect solenoid cable to
solenoid/timer.
6. Reconnect all system air lines.
7.
Test the installation.
1002271b
1
22-30 lb-ft (30-40 N•m)
Revised 11-02
T
MM-35
Page 25
Notes
MM-35
Page 26
Revised 11-02
Appendix I
Glossary
Appendix IGlossary
Basic Air System/Air Dryer Terms
Air Compressor
A device that pumps air to and builds air pressure in an air system.
Air Dryer
A device that cools, filters, and dries the air delivered by an air
compressor.
Air Governor
A device that controls the operation of the air compressor by
constantly monitoring air pressure in the supply tank of the air
system.
The air governor initiates the compressor unload cycle when the
cutout pressure is reached. It also controls the air dryer by sending
an air signal — at the beginning of the compressor unload cycle —
to the control port of the air dryer. This initiates the purge cycle.
When the signal is stopped, the purge valve closes and the drying
cycle begins.
Compressor Load Cycle
The time during which the air compressor is building air pressure in
an air system.
Compressor Unload Cycle
The time during which the air compressor is idling and is not
building air pressure in an air system.
Cut-in Pressure
The pressure level in the air system supply tank that triggers the
compressor load cycle.
Cut-out Pressure
The pressure level in the air system supply tank that triggers the
compressor unload cycle.
Desiccant
A granular substance that has a high affinity for water. It catches and
retains moisture from the air stream.
Drying Cycle
The time during which the air dryer cools, filters and removes
moisture from the air delivered by the air compressor.
Purge
The initial blast of air (decompression) from the air dryer purge
valve at the beginning of the compressor unload cycle.
Purge Cycle
The time during which the air dryer is undergoing purge and
regeneration. It begins at the start of the compressor unload cycle
and normally ends well before the beginning of the compressor
load cycle.
Regeneration
The mild backflow of air through the non-loaded air dryer cartridge
and out the purge valve. A small amount of air from one cartridge is
used to remove moisture from the other cartridge. This readies the
cartridge for the next cycle. The cycle lasts 50–60 seconds, then the
timer switches it to the other cartridge.
Revised 11-02
MM-35
Page 1-A
Notes
MM-35
Page 2-A
Revised 11-02
Appendix II
Application Information
Appendix IIApplication Information
General Requirements
Compressor discharge line should have a continual downhill turn to the air dryer. There should be no water
traps (low points or kinks) in the line before or after the dryer.
Mount air dryer so that there is no direct splash or spray from a wheel.
Keep air dryer at least 12 inches from any heat-producing sources like exhaust manifolds or pipes,
transmissions, etc.
Make sure there are no valves or other devices in the dryer-to-supply-tank line to prohibit or restrict the
flow of air back from the supply tank to the air dryer.
The purge valve must be fed by a direct line from the air governor.
For applications where the working pressure in the system could be lower than 85 psi (for example, bulk
unloading or central tire inflation), install a back-pressure control valve.
Operating Environment Requirements
Figure 1-A
Revised 11-02
Operating Parameter
Requirement
Temperature (ambient
operating range)
–40°F to 175°F
(–40°C to 80°C)
Electrical Power (for heater
and solenoid/timer power)
12 or 24 volts
available
Thermostat Range
(On/Off temp)
45°F, 86°F
(7°C, 30°C)
MM-35
Page 3-A
Appendix II
Operating Environment Requirements, Continued
Figure 2-A
GOVERNOR
COMPRESSOR
INTAKE LINE
UNLOADER
PORT
RESERVOIR
TO GOVERNOR
LINE
SYSTEM SAVER TWIN
AIR DRYER
DRYER
OUTLET
PORT
COMPRESSOR
COMPRESSOR
DISCHARGE
LINE
TO BRAKE
SYSTEM
CHECK
VALVE
CONTROL
(PURGE)
PORT
SYSTEM
RESERVOIR
DRYER
INLET
PORT
SYSTEM
RESERVOIR
SUPPLY
TANK
CHECK
VALVE
1002273d
Discharge Line:
O Diameter from compressor to air dryer
1/2" i.d. minimum
O Length from compressor to air dryer
Determined by temperature of air at the inlet
port of the air dryer. At normal vehicle operating
temperature, length must be sufficient to keep
temperature below 175×F (80×C).
O Recommendations for minimum/maximum
length:
— Under 21 cfm: 6 ft. min./20 ft. max. Use
copper-pipe stainless-steel braided-Teflon
tubing for the first 10 feet (minimum).
Any line over 10 feet should be insulated.
— Over 21 cfm: 10 ft. min./20 ft. max. Use
copper-pipe stainless-steel braided-Teflon
tubing for the first 10 feet (minimum).
Any line over 10 feet should be insulated.
Rated Compressor size:
O Less than 21 cfm
TWIN with 0.8 mm orifice
O Between 21 and 35 cfm
O Greater than 35 cfm
cfm = cubic feet/minute
Pressure Requirements:
O Maximum
140 psi
O Minimum
85 psi
Flow Capacity:
Compressor rating 50 cfm maximum
Compressor On-T ime (normal running):
Unlimited
Maximum Duty Cycle:
100%
MM-35
Page 4-A
Revised 11-02
Appendix II
Installation Instructions for Special Applications
Bulk-Unloading or Central Tire Inflation (CTI) Air Systems
Figure 3-A
Bulk-unloading or CTI air systems require a
back-pressure control valve. Refer to Figure 3-A.
The back-pressure control valve maintains
adequate pressure at the outlet of the dryer to
ensure proper operation in high air usage
applications.
It is installed between the air dryer and the air
distribution system, a minimum of five feet from
the dryer. The arrow on the valve must point in the
direction of the airflow. Refer to Figure 4-A.
NOTE: These instructions are for adding a
back-pressure control valve to an existing TWIN
application. For new installations, refer to TP94104.
NOTE: Back-pressure control valve not required
for Eaton CTI.
1
Arrow points in the direction of airflow.
Installing a Back-Pressure Control Valve
CAUTION
The System Saver TWIN air dryer is designed and engineered to minimize moisture and contaminants in
truck air brake systems. It is not designed to provide moisture-free or contaminant-free air in a bulk
unloading application. The TWIN air dryer should not be used in bulk unloading applications if
contaminants could cause load spoilage. The TWIN air dryer is not to be used in food-grade bulk unloading
applications.
WARNING
or service.
Block the wheels to prevent the vehicle from moving. Support the vehicle with safety stands. Do not work
under a vehicle supported only by jacks. Jacks can slip and fall over. Serious personal injury can result.
Remove all air from the air system before servicing any component in the air system. Pressurized air can
cause serious personal injury.
Revised 11-02
MM-35
Page 5-A
Appendix II
Installing a Back-Pressure Control Valve, Continued
Figure 4-A
RESERVOIR
TO GOVERNOR
LINE
SYSTEM SAVER TWIN
AIR DRYER
TO BULK
UNLOADER
OR CTI
UNLOADER
PORT
DRYER
OUTLET
PORT
CHECK
VALVE
CONTROL
(PURGE)
PORT
COMPRESSOR
DISCHARGE
LINE
TO BRAKE
SYSTEM
SYSTEM
RESERVOIR
SYSTEM
RESERVOIR
DRYER
INLET
PORT
C
B
A
SUPPLY
TANK
CHECK
VALVE
1002275d
Back-Pressure Control Valve (BPCV)
NOTE: Locate the BPCV anywhere BETWEEN the air dryer and the air distribution system.
Points A, B and C show several possible locations for the BPCV. If you select location C, air supply cannot be taken from Line B .
Arrow on BPCV must point in direction of airflow.
NOTE: The end user must provide bulk tank
overpressure protection either in the system or
on the trailer.
1.
Drain all air from the system.
2. Determine where the back-pressure control
valve will be installed. It must be at least 5 feet
from the air dryer. Do not nipple mount the
back-pressure control valve to the dryer.
Refer to Figure 4-A for suggested mounting
locations.
4. Test the installation for leaks.
For part number and order information, refer to
PB-96135. If you need assistance determining
the necessity of a back-pressure control valve
in your application, contact Meritor Customer
Service, 800-535-5560.
3. Find the directional arrow on the replacement
valve.
O Install the valve so that the arrow points in
the direction of airflow.
O Installation orientation is not important.
It does not matter which end faces up or
down.
MM-35
Page 6-A
Revised 11-02
Appendix II
Holset E-Type Compressor Systems
Function
Meritor WABCO offers a special Holset E-Type wiring harness for systems using a Holset E-type
compressor. This harness is shown in Figure 1.18. In addition, an Econ valve, check valve and solenoid
valve assembly are also required. Refer to Figure 5-A.
O E-type compressors can be identified by the serial number tag on the compressor. Tag will indicate:
“This is an E-Type compressor.”
O For proper operation, the discharge line must be kept at reservoir pressure when the governor is in the
unloaded position (compressor not pumping). If this is not done, the compressor will pass excessive oil
into the air system.
Figure 5-A
FROM AIR
COMPRESSOR
DISCHARGE LINE
A
FROM AIR
GOVERNOR
UNLOADER
PORT
RESERVOIR
TO GOVERNOR
LINE
GOVERNOR
TO AIR
DRYER
INLET
PORT
COMPRESSOR
INTAKE LINE
FROM
SUPPLY
TANK
UNLOADER
PORT
UNLOADER
LINE
SYSTEM
SAVER TWIN
AIR DRYER
DRYER
OUTLET
PORT
COMPRESSOR
TEE
FITTING
COMPRESSOR
DISCHARGE
LINE
CHECK
VALVE
ECON
VALVE
(REFER TO
INSET — A)
DRYER
INLET
PORT
SOLENOID
VALVE
(REFER TO
INSET — B)
TO SUPPLY
TANK
CHECK
VALVE
TO BRAKE
SYSTEM
SYSTEM
RESERVOIR
SYSTEM
RESERVOIR
SUPPLY
TANK
CHECK
VALVE
1002276b
B
TO ECON
VALVE
1002276d
NOTE: Normally-closed solenoid valve installed such that when ignition is on, solenoid is energized and
solenoid valve is open, allowing air to flow from supply tank to compressor discharge line.
Revised 11-02
MM-35
Page 7-A
Appendix II
Econ Valve
Econ Valve Ports
O
Inlet Port (1/2"-14 NPTF, female)
Econ Valve Operation
O
Outlet Port (1/2"-14 NPTF, male)
The Econ valve allows supply tank pressure to
reach the compressor discharge line during
compressor idle. When the compressor is
pumping, the Econ valve lets compressor air flow
into the air dryer, then on to the supply tank. When
cutout pressure is reached, the governor unloads
the compressor, and pressurizes Port 4 of the
dryer. This opens the purge valve in the dryer and
expels moisture and contaminants.
O
Unloader Port (1/8" NPTF, marked “UNL” on
valve)
O
Make-up Air Port (1/8" NPTF)
At the same time, the piston in the Econ valve
shifts position and blocks the flow of air into the
dryer. This also allows air to flow from the supply
tank into the compressor discharge line. When the
compressor starts pumping again, the cycle is
repeated.
A check valve at the supply tank prevents air from
bypassing the dryer and going directly to the
supply tank during the pumping cycle. Refer to
Figure 5-A for an illustration of this system.
2. Attach check valve to Econ valve or supply
tank.
3. Reconnect the air lines. Test the system for
leaks.
Replacing the Solenoid Valve
The solenoid valve can be mounted anywhere in
the line between the Econ valve and the supply
tank.
Refer to Figure 5-A.
1.
Remove air from all system tanks. Disconnect
the air line from the solenoid valve.
2. Unplug the solenoid from the wiring harness.
Replacing the Econ and Check
Valves on a Holset E-Type
Compressor System
3. Look at the existing installation and remember
how the old solenoid valve is installed. The
replacement valve will be installed the same
way.
NOTE: When the OEM installed the Holset E-type
compressor system, a one-way check valve, Econ
valve and solenoid valve were plumbed into the
system between the air dryer and the supply tank.
The Econ valve must be located two to seven feet
from the compressor.
4. Remove the old solenoid valve.
1.
Remove air from the system tanks and
disconnect the air lines from the Econ and
check valves. To ensure proper replacement,
use markers to identify the lines. Econ valve
ports are identified below. Refer to Figure 6-A.
Figure 6-A
MM-35
Page 8-A
5. Install the replacement solenoid valve exactly
the way the old valve was installed:
O The normally-closed solenoid must be
installed so that when the ignition is on, the
solenoid is energized and the solenoid valve
is open.
6. Reconnect the solenoid valve to the wiring
harness.
O Insert plug until latch snaps over tab on the
mating connector.
7.
Test the system for leaks.
Revised 11-02
Appendix II
Installing a Turbo Cutoff Valve
Installing the T-Fitting
If your vehicle has a turbocharged engine and the
air compressor draws its intake air from the
pressurized side of the turbocharger (at the intake
manifold or aftercooler), you may want to install a
turbo cutoff valve on your Meritor WABCO air
dryer.
1.
This installation will prevent leakage of turbo
boost through the air compressor and out of the
purge valve of the air dryer when the compressor
is operating in the unloaded mode.
Contact Meritor Customer Service for part number
information (1-800-535-5560).
Remove the unloader line from port 4 on the
air dryer.
2. Install a standard braking systemT-fitting that
has three 1/8-inch NPTF ports on the unloader
line.
3. Connect a line from the T-fitting to port 4 on the
air dryer. Use 1/4-inch (6.3-mm) standard
braking-system nylon tubing.
4. Connect a line from the remaining port on
the T-fitting to the 1/8-inch MPT port marked
“UNL” on the turbo cutoff valve. Use 1/4-inch
(6.3-mm) standard braking-system nylon
tubing.
Installation Instructions
CAUTION
Make sure there are no kinks or sags in the lines
connected to the turbo cutoff valve. Moisture and
dirt can build up and block the lines. The turbo
cutoff valve and the air dryer will not work when
these lines are blocked.
1.
Park the vehicle on a level surface.
2. Stop the engine.
3. Drain pressurized air from all reservoirs to
0 psi (0 bar).
4. Disconnect the delivery line at port 1 on the
air dryer.
NOTE: If there is not enough room to install the
turbo cutoff valve to port 1 on the air dryer,
connect a 90° fitting to port 1 of the air dryer. Then
connect the threaded end of the turbo cutoff valve
to the fitting.
5. Install the threaded end of the turbo cutoff to
port 1 on the air dryer. Make sure the arrow on
the turbo cutoff valve points toward port 1.
6. Connect the delivery line from the compressor
to the 1/2-14 NPT port marked with an arrow
( ) on the turbo cutoff valve.
Revised 11-02
MM-35
Page 9-A
Appendix II
Figure 7-A
FROM AIR
COMPRESSOR
DISCHARGE LINE
A
RESERVOIR
TO GOVERNOR
LINE
FROM AIR
GOVERNOR
UNLOADER
PORT
GOVERNOR
COMPRESSOR
INTAKE LINE
TO AIR
DRYER
INLET
PORT
UNLOADER
PORT
PLUG
UNLOADER
LINE
SYSTEM
SAVER TWIN
AIR DRYER
DRYER
OUTLET
PORT
COMPRESSOR
COMPRESSOR
DISCHARGE
LINE
TEE
FITTING
DRYER
INLET
PORT
CHECK
VALVE
TO BRAKE
SYSTEM
SYSTEM
RESERVOIR
SYSTEM
RESERVOIR
TURBO CUTOFF VALVE
(PLUMB ECON VALVE PER INSET A)
SUPPLY
TANK
CHECK
VALVE
1002278d
Testing the Turbo Cutoff Valve
Final Checks
1.
1.
Close the drain cocks on all reservoirs.
2. Start the vehicle. Wait for the braking system to
pressurize.
3. If you hear the air dryer exhaust air after the
compressor cuts out, the air dryer is working
correctly.
You can also use the following test:
1.
Apply the brakes of the vehicle several times to
reduce pressure in the air system below the
cut-in pressure of the governor.
2. If the air dryer exhausts air after the
compressor cuts out, the air dryer is working
correctly.
MM-35
Page 10-A
Start the vehicle. Wait for the air system of the
vehicle to reach maximum normal pressure.
2. Apply a soap solution to each connection that
contains pressurized air.
a. If soap bubbles do not appear, you
correctly sealed the connections.
b. If soap bubbles appear:
O Turn off the ignition.
O Depressurize all air tanks.
O Remove the leaking connection.
O Apply pipe sealant to the connection.
O Repeat Steps 1 and 2.
Revised 11-02
Appendix II
Vehicle Air System E
This layout is similar to the Cummins “System E” air system arrangement.
Application
Used with high volume air compressors (Meritor WABCO, Holset, Bendix, Knorr, etc.). This air system
arrangement may also be found on vehicles with other engine makes.
Figure 8-A
Min 1/4 I.D. gov line
(down to
condenser tank)
GOV
HIGH VOLUME
AIR COMPRESSOR
TURBO
Set compressor
governor to
130 psi cutout.
15 FT (7/8" I.D.)
TEFLON WIRE
BRAID TUBING
3-WAY NORMALLY OPEN SOLENOID VALVE
WIRED TO IGNITION CIRCUIT
175 PSI
OUT
IN
SAFETY VALVE
WABCO SS TWIN EXH
OPTIONAL TURBO INLET
12 (5/8" I.D.)
LINE
RECEIVER TANK
ENGINE
HEATED SPITTER
TP-95192
2500
CU IN
SYSTEM
STEM SSAVER TWIN
18 SCFM MAX
ACCESSORY PORT
REPLACEMENT CARTRIDGE PART NO. R950011
ENGINE
AIR
FILTER
SUPPLY CHECK VALVE
TANK
PRIMARY
Ensure dryer has
TANK
1 mm orifices in
SPITTER
regen circuit.
CHECK BRAKE
VALVE
SYSTEM
SECONDARY
TANK
2 SCFM Normal usage
for brake system
Maximum air supply volume
is 8000 cubic inches (3 tanks).
1003387a
Revised 11-02
MM-35
Page 11-A
Notes
MM-35
Page 12-A
Revised 11-02
Meritor WABCO
Vehicle Control Systems
3331 West Big Beaver Road, Suite 300
Troy, MI 48084 USA
800-535-5560
meritorwabco.com
Information contained in this publication was in effect at the time the publication was approved for
printing and is subject to change without notice or liability. Meritor WABCO reserves the right to revise
the information presented or discontinue the production of parts described at any time.
Copyright 2002
ArvinMeritor, Inc.
All Rights Reserved
Printed in the USA
Maintenance Manual 35
Revised 11-02
16579/24240

System Saver TWIN Air Dryer

Transcription

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