Carrier Em1 Manual

							4--15 T--311
Figure 4-27 (1)EM--3 Evap, (1)EM--7 Evap, (2) Skirt Condensers and a TM -- 31 Compressor (AC-- 9632)
FILTER
DRIER
FILTER
DRIER 
						

							5-1
T--311
SECTION 5
ELECTRICAL
5.1 INTRODUCTION
Electrical harness routing is a critical process in the
installation of any transportation air conditioning
system. Pre-planning of the electrical harness path
between components will eliminate encounters with
commonly existing conditions which could result in
electrical system failure. Following proper electrical
harness routing procedures will ensure optimum
system performance and provide for a long lasting and
trouble free installation.
5.2 SYSTEM WIRING
5.2.1 Electrical Kits
The electrical kits provided with Carrier Transport Air
Conditioning systems contain the harnesses/cables
and components necessary to safely connect the air
conditioning to the vehicle power source and
communicate signals between components.
Review the wiring diagram to insure that the kit provided
is the proper wiring kit for your air conditioning system.
NOTE
Wiring diagrams are not always supplied. Call
Carrier Transport Air Conditioning customer
service for assistance (1-800-673-2435).
Separate harnesses/cables and route to their
appropriate components. Whenever possible route the
harness/cable with the corresponding components
refrigerant hoses.
5.2.2 Protection
Extreme care must be used when wiring a bus. Plan the
routing of the harness prior to installation, being careful
to avoid sources of high heat and sharp edges. If the
wiring is near any heat source it must be shielded with a
heat resistant insulation. When running the harnesses
through sheet metal or other sharp parts of the vehicle
frame the wires must be protected by grommets or tied
off in a manner that prevents chaffing. Where ever
possible the harness should be routed with the
refrigerant hoses (refer to section 4, Hose Routing).
Failure to protect the air conditioning wiring may result in
wiring shorts and system malfunctions.
Most electrical components are sensitive to heat and
environmental conditions. If at all possible they should
be located in a protected area. All exposed electrical
terminals (connectors) should be coated with an
electrical protectant. Circuit breakers should always be
present and located no further than 24 inches (2 feet)
from the vehicles power source or battery. Failure to
follow these precautions could lead to system failure or
in extreme conditions an electrical short-circuit which
could cause a fire.
All connections must be tight and secure. When any
electrical connection is exposed to the elements it
should be coated with an electrical protectant. Ensure a
solid electrical ground to the vehicle chassis. Failure to
ensure tight, protected connections could cause loss of
power to a component resulting in system failure.5.2.3 Dual Systems
When the bus has a dual compressor system care must
be taken to ensure that the electrical system and hose
routing are independent for each side. Test and charge
one system at a time, thus ensuring each system is
functioning properly. Connecting the piping of one
system to the electrical signals from another system will
result in failures to both systems. It is highly
recommended that both ends of the bus harness/cable
assemblies be marked for ease of identification.
5 . 3 V O LTA G E S
Carrier Transport Air Conditioning components are
designed to operate efficiently at 12.5 or 25 volts. For
continued proper operation, all components must have
a proper voltage supply, even during low idle. After at
least 15 minutes of operation, with all accessories and
the air conditioning system(s) on, check the voltage at
the evaporator, condenser, and the compressor.
Voltages less than 12 volts will cause the condenser and
evaporator fans to run slower, resulting in a pressure
build-up, excess heat, and compressor failure. Less
than 12 volts at the compressor may cause clutch
slippage.
Always be sure that the voltages you are working with is
compatible with the air conditioning system you are
going to install (12 Volt--24 Volt).
5.4 COMPONENT CONNECTIONS
The evaporator, condenser and drivers control panel
are pre-wired and are supplied with a short length of
harness (pig-tail). Connect the color wires from the
appropriate harness/cable to the component (pig-tail)
butt connectors (see Figure 5-1).
Evaporator
Pig-TailEvaporator
Harness/Cable
Figure 5-1 Harness & Pig-Tail Connections
5.4.1 Evaporator Chassis Ground, Gen 4 (Excel)
After connecting to the evaporator assembly pig-tail and
before routing to the electrical control panel, the
evaporator must be grounded to the vehicle chassis as
follows:
Note
The ground should be as close to the evapora-
tor as possible. Insure that the ring terminal is
grounded to bare metal and coated with an
electrical protectant. 
						

							5-2
T--311 a. Carefully make an 8 Inch incision in the evaporator
cable close to where you will attach the ground wire
terminal.
b. Locate the green #10 wire from within the harness/
cable.
c. Cut the green #10 wire and pull from the cable.
d. Strip insulation from wire end and install a 1/4 inch
ring terminal.
e. Remove undercoating or paint from area where
ground will be attached.
f. Securely attach the ground wire terminal with self tap-
ping hardware or bolt (See Figure 5-2 & Figure 5-3).
g. Close incision in the cable with electrical tape.
Incision closed with
electrical tape
Ground
Insulated Clamp
Figure 5-2 Grounded to Clamp
Remove undercoating
secure to bare metal
Figure 5-3 Grounded to Chassis Rail
h. Coat the terminal connection and hardware with an
electrical protectant.
Route other ends of harnesses/cables to the electrical
control panel, which should be in a protected location.
Cut excess harness/cable. Strip harness wires and
attach terminal rings. Connect to the appropriate
terminal strip number on the electrical control panel
(refer to your enclosed system wiring diagram).5.4.2 Evaporator Chassis Ground, Gen 5
Gen 5 evaporators are supplied with a 12 foot section of
green, 10 or 6 gauge wire, depending on the evaporator
assembly. One end of the green grounding wire will have
a #10 ring terminal crimped to it. Securely attach this
end to the evaporator assembly top panel. The other
end of the wire will have a 1/4 inch ring terminal
tie-wrapped to it. Cut the ground wire to desired length,
strip off the insulation, and crimp the 1/4 inch ring
terminal to the wire. The evaporator must then be
grounded to the chassis rail as shown in Figure 5-2/
Figure 5-3 or to the metal frame of the bus roof.
5.5 CONTROLS
One of two control systems may be provided. A Manual
Control Package or a Total Control Package.
5.5.1 Manual controls
If Manual Controls are provided, the controls may be
mounted in a panel (Figure 5-4), without the panel
(Figure 5-5), or as a dual system (Figure 5-6). The
manual controls must be located within easy reach of
the driver. The Drivers Controls consists of an
evaporator fan speed switch (three speed or variable)
and an adjustable thermostat.
NOTE
The Ambient Air Sensor (see Figure 5-4) must
be located within the vehicle’s interior in order to
sense the return air temperature.
1 2 3 45
1Control Panel Housing
2Nameplate (Switch Mounting)
3Thermostat Control Switch
4Fan Speed Switch (3 Speed or Variable)
5Ambient Air Sensor (Thermostat)
Figure 5-4 Drivers Control Panel
Figure 5-5 Controls Mounted Without Panel 
						

							5-3
T--311
Figure 5-6 Drivers Control Panel (Dual Systems)
5.5.2 Electrical Control Panel
The manual controls are wired to the electrical control
panel (see Figure 5-7) The panel contains relays and
circuit breakers used for system control. It must be
located in an area that is protected from heat, moisture,
dirt, and road hazards.
12
3
4
5
6
1. High Speed Relay
2. Condenser Relay
3. Compressor Clutch Relay
4. Circuit Breaker (HSR)
5. Circuit Breaker (CR)
6. Circuit Breaker (Ignition)
Figure 5-7 Electrical Control Panel (Typical)
5.6 TOTAL CONTROL
The Total Control system consists of a Key Pad Display
(Figure 5-8), an Electrical Control Panel, (Figure 5-9)
and inter connecting wiring. The Key Pad Display must
be located within easy reach of the vehicle operator.
1
2
3
4
5
6 8 9 10 1112
7
1 Display
2 Green LED, Cool Mode
3 Red LED, Heat Mode
RedLED,Flash,Alarm
4 ON Button
5 OFF Button
6 Increase Selection
7 SET Button
8 Decrease Selection
9 Fan Speed Button
10 Green LED, Inside Temperature
11 Green LED, Set Point
12 Total Control Mounting Assembly
Figure 5-8 Total Control Key Pad/Display
5.6.1 Total Control Electrical Control Panel
The key pad/display is wired to the Total Control
electronic control panel (lFigure 5-9). The panel
contains relays, circuit breakers, and the
microprocessor used for system control. It must be
located in an area that is protected from heat, moisture
and road hazards.
Care must be taken when routing the return air sensor
(thermistor) cable and the cab command cable. Both 
						

							5-4
T--311 these cables can be damaged easily if pulled across
rough or sharp areas of the bus chassis or A/C system.
1
234
5678
Figure 5-9 Total Control Electrical Panel (Typical)1Logic Module (Speed Control)
2Fuse(5Amp
3Circuit Breaker (Condenser)
4Circuit Breaker (High Speed)
5Clutch relay
6Relay Filter - PWM (Pulse Width Modulation)
7Condenser Relay
8High Speed Relay
NOTE
A completely wired Gen 5 dual system total
control is shown in Figure 5-10. Notice that the
system control panels are labeled front and
rear. They can also be labeled left or right if side
mounted evaporators are used. A easily remov-
able cover was also fabricated for this installa-
tion.
Figure 5-10 Gen 5 Total Control (Dual System)
5.7 OPERATING INSTRUCTIONS
Before attempting to operate the system, power must
be available from the vehicle battery. If the engine is notrunning, start the engine. For complete operating
instructions refer to operation and service manual T-299
Split-Systems. 
						

							6-1 T-- 311
SECTION 6
MOUNT KITS AND COMPRESSORS
6.1 INTRODUCTION
Carrier transport Air Conditioning offers a wide range of
compressors and corresponding mount kits for most en-
gine-chassis combinations. Carrier Transport Air Condi-
tioning mount kits are engineered to allow precise align-
ment and belt tensioning adjustments.
The mount and drive kit normally will contain the
mounts, hardware, pulleys, belts, idlers, etc. necessary
to safely mount the compressor to the bus engine.
Read and follow the installation instructions supplied
with each mount kit. Always check the Rev. number on
the drawing to determine if there have been any
changes to the mount kit since your last installation.
Minor modifications are occasionally necessary and are
considered part of the installation process. These
mount and drive kits are designed to fit vehicles with
standard equipment. The addition of special or optional
equipment may interfere with the normal installation.
It is important that the compressor have a solid mount
with no stress. The spacing between the compressor
mounting ears and the compressor mount may vary
slightly due to the manufacturing tolerances. Use shims
to close any gap between the compressor ears and
mount,before tightening the compressor mounting
bolts.
Always check pulley and belt alignment and shim as
necessary. Failure to align can cause premature wear,
belt squeal, and vibration. Use a straight edge to deter-
mine proper pulley and belt alignment before securing
the mounting hardware (Refer to paragraph 6.3).
Always torque to the specifications noted on each
mount kit installation instructions. Refer to Figure 6-2
through Figure 6-3 for torque specifications not noted
on the installation drawing.
When a non-permanent or permanent thread-lock is
supplied with the mount kit, use where and how speci-
fied per the mount kit installation instructions.
Some installations may require a slight modification or
rearrangement of the radiator mounting, turbo tubes,
fuel lines, reservoirs, water lines, harnesses, or the oil fill
tube for proper clearance.
On some applications it may be necessary to install the
refrigerant hose and fittings to the auxiliary compressor
before mounting and securing.If system is a “Tie-In” to factory dash air, the refrigerant
must be removed with an EPA approved recovery ma-
chine. This recovered refrigerant should then be re-
cycled and reused.
Note
When the OEM radiator condenser is discon-
nected (not used), it is recommended by Carrier
Transport Air Conditioning that it be removed
from the vehicle.
Following established mount and drive installation pro-
cedures will enure proper belt alignment and tensioning,
which in turn will promote long belt life and optimum sys-
tem performance.
6.2 INSTALLATION
Utilize the following procedures when installing a Carrier
Transport Air Conditioning mount kit and compressor:
a.Unpack and inspect components for damage.
b.Insure the mount kit will fit the engine assembly.
c.Lay out all brackets, pulleys, hardware, etc. and iden-
tify using the enclosed packing list.
d.If alterations to engine heater hose is necessary,
drain coolant. Save coolant for later use.
e.Disconnect negative battery cable.
f.Follow the mount kit sequence instructions when
installing the weldments, brackets, etc., making sure
all bolts are tight, and the correct washers are used.
g.Use thread-lock whenever noted, and torque bolts to
specifications listed on drawing. Refer to Figure 6-2
through Figure 6-3 for torque specifications not noted
on the installation drawing.
Note
Never substitute the graded hardware that is
supplied with the mount kit.
Note
Never use an air impact tool to tighten bolts on a
mount or compressor. Use a torque wrench.
Note
Always use every bracket, support, and stiffen-
er furnished with the kit. 
						

							6-2 T--311 6.2.1 TORQUE SPECIFICATIONS
Always torque to the specifications noted on each
mount kit installation instructions. The torque values
listed in Figure 6-2 and Figure 6-3 are are based on the
use of lubricated threads.
BltSi
Torque(FtLbTorque(FtLbTorque(FtLbBolt SizeDia.mm
q(Ft-Lb
CastIron
q(Ft-Lb
CastIron
q(Ft-Lb
CastIronDia.mmCastIronGrade 8.8CastIronGrade 10.9CastIronGrade 12.9
677109139187
8
10
1
8
13
2
3
18
27
810
12
1830
55
2345
75
2750
9512
1455
8575
12095
14514
16
85
130
120
175
145
210
Figure 6-1 Metric Torque Specs
8.810.9
12.9 Commercial Grade Head Markings
Metric Bolts
Grade 8.8 Grade 10.9
Grade 12.9
Figure 6-2 Metric Bolt Markings
Bolt Size
Dia. mm
Torque
(Ft-Lb)
Cast Iron
Grade 2Torque
(Ft-Lb
Cast Iron
Grade 5Torque
(Ft-Lb
Cast Iron
Grade 8
1/4-205/16-1851071511225/16-18
3/8-167/16-14
10
1830
15
3045
22
40657/16-14
7/16-201/2-13
30
3245
45
5070
65
70951/2-13
1/2-205/811
45
5082
70
75135
95
11 01905/8-11
5/8-18
82
93
135
155
190
215
Figure 6-3 U.S.S. Torque Specs
Commercial Grade Head Markings
U.S. Customary Bolts
Grade 5
Grade 8Grade 2
Figure 6-4 U.S.S. Bolt Markings6.3 DRIVE BELT INSTALLATION
6.3.1 Introduction
There are several factors that have major effects on
compressor and alternator drive belt(s) life expectancy
and reliability. Belt alignment and proper tension being
the most critical and controllable by the installer and
end-user. Improper alignment and/or tension will cause
premature failure of drive belts, driven components as
well as a possible safety issue. When improperly
installed and/or maintained, drive belts can cause
significant damage to equipment as well as service
personnel. This document will act as a guideline for
proper installation instruction as well as continuous
maintenance guidelines which when followed insures
years of trouble free service. The following are the
biggest factors that effect belt life and system
dependability.
A. Belt Alignment
B. Belt Tension
1. Over Tensioned
2. Under Tensioned
C. Belt Clearance
D. Temperature-Heat
E. Fluids
F. Maintenance Procedures
This document acts as a guide only. This document will
not replace proper installation training and/or
experience required for Carrier A/C Certification. As
always, take special caution when working with running
engines and drive belts. Safety glasses or goggles must
be worn at all times. Loose clothing is also extremely
dangerous around moving pulleys and belts.
For questions or concerns not covered here, please feel
free to contact the Carrier Transport Air Conditioning
Technical Service Hotline at (800) 450-2211.
6.3.2 Belt Clearance
A certain belt clearance needs to be provided for belt
span vibration when installing compressors and
alternator belts. Figure 6-5 shows the recommended
clearance guidelines for preliminary layout work. Due to
the large number of variables, actual testing is required
to determine whether the clearances are acceptable. 
						

							6-3 T-- 311
Clearance Zone IdentificationClearance at Mid Span
Figure 6-5 Belt Clearance Requirements
6.3.3 Pulley Alignment
Correct belt alignment is essential for alternator and
compressor belt life. The center line of all pulleys related
to compressor or alternator drive must be within 1/3
degree of true center. Refer to Figure 6-6 for
approximate measurements, and keep in mind, these
are maximum values. You should try to attain perfect
alignment whenever possible to maximize component
and belt life.
Maximum allowable run-out for Poly ”V” belts is 1/8 inch.
Maximum allowable run-out for Standard ”V” belts is 1/4
inch.
Methods and tools used in determining proper
alignment are illustrated in Figure 6-6 and Figure 6-7. A
high quality straight edge is a necessity, your eye is not
an acceptable method of determining proper belt
alignment. Precision Tools make a line of straight edges
that would be suitable for compressor and alternator
alignment purposes. Other alternatives are available
please call Carrier Transport Air Conditioning Technical
Hot Line at 1-800-450-2211 with any questions
orcomments. All mounting brackets should allow for
minor belt center line adjustments.
Parallel
MisalignmentAngular
Misalignment
Figure 6-6 Belt MisalignmentParallel adjustment is designed into a mount for final
alignment during the installation process. This is
necessary due to manufacturing and engine tolerances
as well as multiple applications and different engine
options available. Parallel misalignment is corrected by
moving the driven pulley (alternator or compressor) into
alignment with the drive pulley. This can be done using
several methods. Spacing the component forward or
rearward by adding or removing spacers is the most
popular method used to achieve proper alignment.
Other methods such as sliding the component forward
or rearwards using slide plates and/or slots in the main
weldment are also used.
Angular misalignment is often caused by tolerances in
several pieces, such as hardware to mounting holes and
plates to components. This could also be from a poorly
built design and/or installed bracket. Excessive
modifications such as grinding or drilling holes to a
larger diameter to apply/install a kit should be avoided
when possible. Minimizing tolerances must be
considered during the design process to minimize this
problem. Angular misalignment is corrected by
loosening the mounting hardware, adjusting the
compressor to the proper angle and retightening the
mounting hardware.
CorrectIncorrect
Figure 6-7 Straight-Edge Application
Proper use of a straight edge is illustrated in Figure 6-7 .
Never use a straight edge on the wide/flat side, as they
are not accurate. The thin edge is a straight surface and
the only accurate surface. The straight edge must be
flush across the face of the pulley. Then, to measure the
alignment, lower the other end down to the driven
pulley(s). Adjustments are made based on results of the
aforementioned. Note that the pulley rim width must be 
						

							6-4 T--311 considered when making the aforementioned
measurements.
The next step is to lay the straight edge flush across the
face of the driven pulley. This is the best way to
determine angular misalignment. Again, adjust as
required. You should repeat this step for all pulleys until
acceptable alignment is achieved. Note the drive pulley
is the primary guide for alignment. Do not use idlers as a
guide for proper component belt alignment as bearing
play could give you false readings.
6.3.4 Drive Belt Tension-Guidelines
Proper belt tension is essential for not only belt life, but
also the alternator and compressor life as well. Heat is a
major enemy of compressors and alternators that can
cause unnecessary stress and greatly reduce
component life.
Listed in Figure 6-8 are the examples specific to belt
tension concerns:
A.Under tension would promote belt slippage causing
excessive heat. Heat equals premature alternator
and/or compressor failure.
B.Over tension could cause premature bearing failure
and excessive wear on drive and driven components.Proper belt tension is obtained by referring to Figure 6-8
. Find the belt used and where applied (compressor or
alternator drive, Single ”V” or Poly ”V” 4-8 ribs).
Notice that new belt tension is higher than in-service or
re-tension amount. All new belts require a run-in period.
During this period, a new belt will stretch more in a 10
hour run time than the entire life of the belt. So it is
important to recheck belt tension after run-in or
re-tension new belts if less than re-tension amount
prescribed above. You should check belt tension with
the belt ”hot.” However, the belt must be allowed to cool
before re-tensioning. Drives which incorporate
automatic tensioners do not require a run-in period or
re-tensioning.
6.3.5 Measuring Methods for Belt Tension
There are several methods and tools available for
determining belt tension. The industry’s acceptable
method would be to use a belt tension gauge as
manufactured by Kent-Moore or approved equal (CTD
Part Numbers 07-00203-00 for non-cogged V-belts &
07-00253-00 for Poly-V’s). There are also several other
models available than can be used. Please follow
manufacturer guidelines regarding gauge selection
operation and calibration requirements. You must get
the correct tension gauge for your specific belt type(s).
Drive
Belt Top WidthNew Belt
Lbs. TensionRe-Tension
Lbs. TensionRe-Tension
Threshold
AlternatorAll11 09070
CompressorAll13010580
Poly-Rib Belt
& Serpentine Drive6orMoreRibs14510590
Figure 6-8 Belt Tension Guide
6.4 COMPRESSOR INSTALLATION
6.4.1 Installation Position
The compressor should be installed on the vehicle
within the range shown in Figure 6-9. If installed outside
the range shown in Figure 6-9 the compressor will be
adversely affected. Most split system compressors are
equipped with a pressure feed lubrication system which
cannot function properly if the compressor is installed
outside this range. As a precaution, it is recommended
that once the compressor is mounted in its proper and
final position, the compressor clutch is turned over by
hand at least 10 revolutions before installation of the
drive belt up to the pulley. If this is not done before the
compressor is put into service, damage to the compres-
sor valves can result from oil slugging. This is not cov-
ered under warranty.
6.4.2 Installation Precautions
The new compressor is (should be) filled with the specif-
ic quantity of compressor oil and nitrogen gas. When
mounting the compressor on the vehicle, take the fol-
lowing steps:a. Loosen the discharge side connector ’s cap and gent-
ly release the nitrogen from compressor. Take care
not to let oil escape.
b. Slowly rotate the compressor ’s magnetic clutch sev-
eral times by hand to distribute the oil which has
settled in the cylinders.
c. When replacing the compressor on a system, the
compressor should be installed after adjusting the
amount of oil. (Refer to T-299 Operation and service -
Split Systems) When installing the compressor on a
new system, be sure to follow factory guidelines.
6.4.3 Mounting Compressors
Clearance between the compressor mounting supports
(ears) and its bracket must be less than 0.004 inches
(0.10mm). Use shims as necessary to adjust this clear-
ance. This will reduce the stress on the compressor
which can cause components to fail. Be sure to maintain
proper pulley alignment for the drive belt.
It is important that the compressor be mounted properly
when installed (See Figure 6-9). The side to side mount-
ing angle of the compressor must remain±45°from the
horizontal. The forward to backward angle must be with-
in±10°of horizontal. 
						

							6-5 T-- 311 Note
The side to side mounting angle of the A-6 com-
pressor must remain±15°from the horizontal
(See Figure 6-9).
Access to the air conditioning service ports will vary. If
access cannot be made at the compressor, in-line ser-
vice ports must be installed as close to the compressor
as possible.
Special care must be used when routing the suction and
discharge hoses through the engine compartment.
These hoses must be kept away from sharp objects and
hot areas of the engine. Damage to the refrigerant
hoses and leaks may occur. The hot areas can also re-
duce capacity by adding heat into the refrigerant inside
the hoses. This added heat must then be rejected by the
condensing coil. Since each coil has a limited ability to
reject heat, that kind of extra heat simply means less
cooling inside the bus where it is needed.6.4.4 Oil Charge
Each compressor comes with a standard charge of oil
inside. This quantity of oil is enough to supply the com-
pressor lubrication when installed into an already “oil
wet” system. New systems require an extra quantity of
oil be added to “wet” all interior surfaces of the system.
Refer to Section 8, Charging Procedures, for the
approximate refrigerant and oil amounts.
CAUTION
Verify that the oil added to the air condition-
ing system is the same oil that is in the com-
pressor. The mixing of incompatible oils
will damage your system.
Refer to Section 7 for evacuation, Section 9 for leak
checking, and Section 8 for charging procedures. Refer
to Section 4 for hose routing.
S
D
A-- 6 COMPRESSOR
90°45°
15°
15°
10°
10° 10° 10°
FRONT TO REAR ANGLESIDE TO SIDE ANGLE
Figure 6-9 Compressor Mounting Angles