MCC EM-1 User manual

OPERATION AND SERVICE
for
SPLIT SYSTEMS
Generation 4 & 5
REV. 08/2012
T-299 Manual
T-299 Manual
©2012 Mobile Climate Control

©2012 Mobile Climate Control T-299 Rev. 08/2012
Safety --1
SAFETY SUMMARY
GENERAL SAFETY NOTICES
The following general safety notices supplement the specific warnings and cautions appearing elsewhere in this
manual. They are recommended precautions that must be understood and applied during operation, service,
and maintenance of the equipment covered herein. The general safety notices are presented in the following
three sections labeled: First Aid, Operating Precautions and Maintenance Precautions. A listing of the specific
warnings and cautions appearing elsewhere in the manual follows the general safety notices.
FIRST AID
An injury, no matter how slight, should never go unattended. Always obtain first aid or medical attention
immediately.
OPERATING PRECAUTIONS
Always wear protective eye wear (safety glasses or goggles).
Keep hands, clothing and tools clear of the evaporator and condenser fans.
No work should be performed on the system unless battery power is disconnected.
Always work in pairs. Never work on the equipment alone.
In case of severe vibration or unusual noise, stop the system and investigate.
MAINTENANCE PRECAUTIONS
Familiarize yourself with the proper operation of any service equipment you will be using (voltmeter, amp
probe, manifold gauges, etc.). Always read the owner's manual that is enclosed with the equipment
Always follow the manufacturers instructions for your recovery/recycling equipment. Failure to do so could
cause personal injury or damage to your equipment. Never perform any maintenance or service on your
equipment before consulting with authorized service personnel. Always unplug unit before attempting any
maintenance. Removing internal fittings and filters can release pressurized refrigerant. Slowly release pressure
and always wear appropriate safety wear.
Avoid breathing any refrigerant vapor, lubricant vapor, or mist. Exposure to these, particularly PAG oil mist,
may irritate your eyes, nose, or throat.
Always use a DOT (Department of Transportation) approved cylinder for storing used and recycled
refrigerant. Approved cylinders will be stamped DOT 4BW or DOT 4BA. MCC recommends a MACS(Mobile
Air Conditioning Society) certification in Recovery/Recycling to gain more information on handling and using
refrigerants.
Never attempt to apply heat or open flame to a refrigerant cylinder. High temperatures can raise the cylinder
pressure to dangerous levels. MCC recommends using a heat blanket to increase the internal temperature of the
refrigerant cylinder, greatly increasing the transfer of refrigerant to the bus air conditioning system.
Never use compressed air (shop-air) to leak-test or pressure test a R134a system. Under certain conditions,
pressurized mixtures of R134a and air can be combustible. In addition, shop air will inject moisture into the
system.
Always use mineral oil to lubricate “O” Rings, hoses, and fittings on R134a systems.PAG oils will absorb
moisture and become very acidic and corrosive. Mineral oil will not absorb moisture and thus prevent
corrosion. Always wear gloves when working with PAG and Ester lubricants to prevent irritation to your skin.
R134a lubricants can also damage vehicles paint, plastic parts, engine drive belts and coolant hoses.
Beware of unannounced starting of the evaporator and condenser fans.Do not remove the evaporator cover or
condenser fan guards without disconnecting the vehicle battery cable.
Be sure power is turned off before working on motors, controllers, and electrical control switches. Tag system
controls and vehicle battery to prevent accidental energizing of the system.

Safety - 2
©2012 Mobile Climate Control T-299 Rev. 08/2012
Do not bypass any electrical safety devices, e.g. bridging an overload, or using any sort of jumper wires.
Problems with the system should be diagnosed, and any necessary repairs performed, by qualified service
personnel.
When performing any arc welding on the vehicle, disconnect the vehicle battery.
In case of electrical fire, extinguish with CO2(never use water). Disconnect vehicle battery power if possible.
SPECIFIC WARNINGS
WARNING
Beware of unannounced starting of the evaporator and condenser fans. The unit may cycle the
fans and compressor unexpectedly as control requirements dictate.
WARNING
Be sure to observe warnings listed in the safety summary in the front of this manual before per
forming maintenance on the air conditioning system
WARNING
Never use air for leak testing. It has been determined that pressurized, air-rich mixtures of re
frigerants and air can undergo combustion when exposed to an ignition source.
WARNING
Do not use a nitrogen cylinder without a pressure regulator. Do not use oxygen in or near a
refrigeration system or as an explosion may occur.
WARNING
To prevent trapping liquid refrigerant in the manifold gauge set be sure set is brought to suc
tion pressure before disconnecting.
WARNING
There may be liquid refrigerant trapped behind the block valve. Slowly loosen the fitting and avoid
contact with exposed skin or eyes.
WARNING
The filter-drier may contain liquid refrigerant. Slowly open the fitting nuts and avoid contact with
exposed skin or eyes.
CAUTION
Unless there was a catastrophic failure, such as a blown or ruptured refrigerant hose, additional
oil may not be needed.

©2012 Mobile Climate Control T-299 Rev. 08/2012
Safety --3
CAUTION
Use only the exact oil specified by the compressor manufacturer. Use of oil other than that spe
cified will void the compressor warranty.

1
©2012 Mobile Climate Control T-299 Rev. 08/2012
Table of Contents
SAFETY SUMMARY Safety -1...............................................................
SPECIFIC WARNINGS Safety -2......................................................
SECTION 1 1-1............................................................................
DESCRIPTION 1-1....................................................................
1.1 INTRODUCTION 1-1.......................................................
1.2 WHAT IS AIR CONDITIONING 1-1...........................................
1.3 MODEL AND SERIAL NUMBER TAGS 1-1.....................................
1.4 SYSTEM REQUIREMENTS LABEL 1-5........................................
1.5 SYSTEM DESIGNATIONS 1-5................................................
1.6 SYSTEM COMPONENTS 1-5.................................................
1.7 REFRIGERATION SYSTEM COMPONENT SPECIFICATIONS 1-6.................
a. EXPANSION/BLOCK VALVE: 1-6......................................................
b. PRESSURE SWITCHES: 1-6.............................................................
c. FREEZE-UP THERMOSTAT: 1-7........................................................
d. RETURN AIR THERMOSTAT/SENSOR 1-7...............................................
e. EVAPORATOR MOTORS 1-7...........................................................
f. CONDENSER MOTORS 1-7............................................................
g. COMPRESSORS 1-7...................................................................
1.8 COOLING CYCLE 1-7.......................................................
1.9 HEATING CYCLE (If Applicable) 1-10...........................................
SECTION 2 2-1............................................................................
OPERATION 2-1......................................................................
2.1 OPERATING INSTRUCTIONS 2-1............................................
2.2 MANUAL CONTROLS 2-1...................................................
2.2.1 Driver's Control Panel 2-1...............................................................
2.2.2 Fan Speed Switch (three speed or variable) 2-1................................................
2.2.3 Thermostat Control 2-1.................................................................
2.2.4 Electrical Control Panel 2-1..............................................................
2.3 FLORIDA CONTROL (TEMPCON) 2-2........................................
2.3.1 ON/OFF Function 2-2.................................................................
2.3.2 Fan Speed Switch - 3 Speed 2-2...........................................................
2.3.3 Adjusting Set Point (Interior Temperature Adjustment) 2-2......................................
2.4 IN-LINE FUSE (FLORIDA CONTROL) 2-2.....................................
2.5 TOTAL CONTROL 2-3......................................................
2.5.1 Total Control Operation 2-3...................................................
2.6 GEN 4 - WITH TOTAL CONTROL, UNIT OPERATING INSTRUCTIONS 2-5........
2.7 PRE-TRIP INSPECTION 2-5..................................................
2.8 SEQUENCE OF OPERATION 2-5.............................................
2.8.1 Three Position Switch Operation 2-5.......................................................

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Table of Contents
2.8.2 Variable Speed Control Operation 2-6......................................................
2.8.3 Total Control - Gen 5 Operation 2-6.......................................................
2.8.4 Total Control - Gen 4 Operation 2-6.......................................................
2.8.5 Heat Option 2-7.......................................................................
2.9 EnviroMATE Controller (Single Zone) 2-8........................................
2.9.1 Controller Operation 2-8................................................................
2.9.2 Evaporator Fan Operation 2-8............................................................
2.9.3 Cooling Mode 2-9......................................................................
2.9.4 Heating Mode (If equipped) 2-9...........................................................
2.9.5 Sensors 2-9...........................................................................
2.9.6 Voltage 2-9...........................................................................
2.9.7 Schematics 2-9........................................................................
2.9.8 Alarm Descriptions 2-10..................................................................
2.10 EnviroMATE Controller (Dual Zone) 2-11.........................................
2.10.1 Controller Operation 2-11................................................................
2.10.2 Evaporator Fan Operation (Automatic) 2-12..................................................
2.10.3 Evaporator Fan Operation (Manual) 2-12.....................................................
2.10.4 Cooling Mode 2-12......................................................................
2.10.5 Heating Mode (If equipped) 2-13...........................................................
2.10.6 Sensors 2-13...........................................................................
2.10.7 Voltage 2-13...........................................................................
2.10.8 Schematics 2-13........................................................................
2.10.9 Alarm Description (Dual Zone) 2-14........................................................
SECTION 3 3-1............................................................................
TROUBLESHOOTING 3-1..................................................................
3.1 INSUFFICIENT OR NO COOLING 3-1. ..........................................
3.1.1 Preliminary Checks 3-1.. .....................................................................
3.1.2 Checking System Air Output 3-1.. .............................................................
3.1.3 Check The Sight Glass For Bubbles 3-1.. ........................................................
3.1.4 Compressor Amp Draw 3-1.. .................................................................
3.2 SYSTEM WILL NOT COOL 3-4. .................................................
3.3 SYSTEM RUNS BUT HAS INSUFFICIENT COOLING 3-4. ...........................
SECTION 4 4-1............................................................................
SERVICE 4-1........................................................................
4.1 PREVENTATIVE MAINTENANCE SCHEDULE 4-1.............................
4.2 MAINTENANCE PROCEDURES 4-2..........................................
4.3 INSTALLING MANIFOLD GAUGES 4-2.......................................
4.4 REFRIGERANT RECOVERY 4-5..............................................
4.5 REFRIGERANT LEAK CHECKING 4-5........................................
4.6 EVACUATION AND DEHYDRATION 4-5.....................................
4.6.1 General 4-5...........................................................................

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Table of Contents
4.6.2 Preparation 4-5........................................................................
4.6.3 Procedure For Evacuation and Dehydrating System (Triple Evacuation) 4-6.........................
4.7 PROCEDURE FOR EVACUATION AND DEHYDRATING SYSTEM 4-6............
4.8 ADDING REFRIGERANT TO A SYSTEM 4-6...................................
4.8.1 Checking Refrigerant Charge 4-6..........................................................
4.8.2 Adding Full Charge 4-6.................................................................
4.8.3 Adding Partial Charge 4-6................................................................
4.9 COMPRESSOR(S) 4-7........................................................
4.9.1 Evaporator Tie-In 4-9.. ...................................................................
4.10 TORQUE SPECIFICATIONS - REFRIGERANT FITTINGS 4-11.....................
4.11 TORQUE SPECIFICATIONS - BOLTS 4-11......................................
4.11.1 Electrical Control Panel - Torque Values 4-11.................................................
4.12 DRIVE BELT INSTALLATION 4-12............................................
4.12.1 Introduction 4-12.......................................................................
4.12.2 Belt Clearance 4-12......................................................................
4.12.3 Pulley Alignment 4-12...................................................................
4.12.4 Drive Belt Tension Guidelines 4-13.........................................................
4.12.5 Measuring Methods for Belt Tension 4-14....................................................
4.13 RETURN AIR FILTER 4-14....................................................
4.13.1 GEN 4 (EXCEL) Series 4-14..............................................................
4.13.2 GEN 5 Series 4-14......................................................................
4.14 EVAPORATOR BLOWER AND/OR MOTOR ASSEMBLY 4-15.....................
4.14.1 GEN 4 Series 4-15......................................................................
4.14.2 GEN 5 Series 4-15......................................................................
4.15 RESISTORS 4-15.............................................................
4.15.1 GEN 4 Series (Excel) 4-15................................................................
4.15.2 GEN 5 Series 4-15......................................................................
4.16 CONDENSER FAN ASSEMBLY 4-16...........................................
4.17 REPLACING THERMOSTATIC BLOCK VALVE 4-16.............................
4.18 CHECKING AND REPLACING HIGH PRESSURE SWITCH 4-16...................
4.18.1 Replacing High or Low Pressure Switch 4-16.................................................
4.18.2 Checking High Pressure Switch 4-16........................................................
4.19 MOISTURE INDICATOR (SYSTEM) 4-17........................................
4.20 FILTER-DRIER OR RECEIVER-DRIER 4-17.....................................
SECTION 5 5-1........................................
ELECTRICAL SCHEMATIC DIAGRAMS 5-1.....................................................
5.1 INTRODUCTION 5-1.......................................................

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©2012 Mobile Climate Control T-299 Rev. 08/2012
List of Tables
Table 1-1 Additional Support Manuals 1-1................................................
Table 3-1 Evaporator Current Draw (GEN 4) 3-2..........................................
Table 3-2 Evaporator Current Draw (GEN 5) 3-3..........................................
Table 3-3 Condenser Current Draw (GEN 5) 3-3...........................................
Table 3-4 GENERAL SYSTEM TROUBLESHOOTING PROCEDURES 3-4...................
Table 3-4 GENERAL SYSTEM TROUBLESHOOTING PROCEDURES - Continued 3-5.........
Table 4-1 Split System Refrigerant And Oil Charging Table - Thru GEN 4 4-8....................
Table 4-2 SPLIT SYSTEM REFRIGERANT AND OIL CHARGING TABLE (GEN-5) 4-8.......
Table 4-3 SPLIT-SYSTEM GEN-5 WITH MICRO-CHANNEL CONDENSER 4-8..............
Table 4-4 Compressor Oil Type & Part Numbers 4-9.......................................
Table 4-5 Mobile Climate Control SYSTEM PERFORMANCE CHART 4-10.....................
Table 4-6 STANDARD TORQUE REQUIREMENTS 4-11..................................
Table 4-7 Metric Torque Specs 4-11......................................................
Table 4-8 U.S. Torque Specs 4-11........................................................
Table 4-9 Belt Tension Guide 4-14.......................................................
Table 4-10 R-134a Temperature - Pressure Chart 4-19........................................
List of Figures
Figure 1-1 Condenser Model CM2/3 - Serial Number Location 1-2............................
Figure 1-2 GEN 4 Evaporator Model - Serial Number Location 1-2...........................
Figure 1-3 GEN 5 Evaporator Model (All) - Serial Number Location 1-2.......................
Figure 1-4 GEN 4, IW-2 & IW-7 - Serial Number Location 1-3...............................
Figure 1-5 GEN 4, IW-1 - Serial Number Location 1-3.....................................
Figure 1-6 CM-7/11 Rooftop Condensers (No Longer Offered) - Serial Number Location 1-4.......
Figure 1-7 KR-2/KR-3 Rooftop Condensers - Serial Number/PID Location 1-4.................
Figure 1-8 System Requirements Label 1-4...............................................
Figure 1-9 Component Location Diagram 1-6............................................
Figure 1-10 Air Conditioning Refrigerant Flow Diagram - Small Split System 1-9..................
Figure 1-11 Heating System Flow Diagram (Typical) 1-10....................................
Figure 2-1 Drivers Control Panel 2-1...................................................
Figure 2-2 Electrical Panel (Typical) 2-1.................................................
Figure 2-3 Switch Assembly (TEMPCON) 2-2............................................
Figure 2-4 In-Line Fuse & Holder (3 Amp) 2-2...........................................
Figure 2-5 Total Control Key Pad/Display 2-3............................................
Figure 2-6 Null Band 2-4............................................................
Figure 2-7 Total Control Electrical Control Panel (Typical) 2-4...............................
Figure 2-8 EnviroMATE Control Panel 2-8..............................................
List of Figures

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©2012 Mobile Climate Control T-299 Rev. 08/2012
Figure 2-9 EnviroMATE Alarms (Single Zone) 2-10........................................
Figure 2-10 EnviroMATE Control Panel 2-11.............................................
Figure 2-11 EnviroMATE Alarms (Dual Zone) 2-14........................................
Figure 4-1 Manifold Gauge Set 4-2.....................................................
Figure 4-2 Refrigerant Service Connections (Split Systems) 4-4...............................
Figure 4-1 Micro-Channel Style Condenser Assembly 4-9...................................
Figure 4-3 Metric Bolt Markings 4-11....................................................
Figure 4-4 U.S. Bolt Markings 4-11......................................................
Figure 4-5 Belt Clearance Requirements 4-12..............................................
Figure 4-6 Belt Misalignment 4-13......................................................
Figure 4-7 Straight-Edge Application 4-13................................................
Figure 4-8 GEN 4 Series Resistor Assembly 4-15...........................................
Figure 4-9. Checking High Pressure Switch 4-17............................................
Figure 4-10 Filter Drier 4-18...........................................................
Figure 4-11 Receiver-Drier 4-18........................................................
Figure 5-1 Electrical Schematic Diagram - Symbols 5-1.....................................
Figure 5-2 Legend - Electrical Schematic Diagrams 5-2.....................................
Figure 5-3 GEN 4 System Schematic - EM-1 With CM-2/3 5-3...............................
Figure 5-4 GEN 4 System Schematic - EM-1 With CM-2/3 - Tie-In 5-4........................
Figure 5-5 GEN 4 System Schematic - EM-3 With (2) CM-3 Condensers & (2) Compressors 5-6.....
Figure 5-6 GEN 5 Evaporator (With Variable Speed Control) Schematic 5-6....................
Figure 5-7 GEN 5 System Schematic With Total Control 5-7.................................
Figure 5-8 GEN 4 EM-3 With (2) CM-3 With Total Control - System Schematic 5-8..............
Figure 5-9 GEN 4 Series With Total Control 5-9..........................................
Figure 5-10 Gen V with EnviroMATE Controller (Single Zone) 5-10...........................
Figure 5-11 Gen V with EnviroMATE Controller (Dual Zone, 2 Evaps., 2 condensers, 2 Comps.) 5-11.
Figure 5-12 Gen V with EnviroMATE Controller (Dual Zone, 3 Evaps., 2 condensers, 2 Comps.) 5-12.

1--1
©2012 Mobile Climate Control T-299 Rev. 08/2012
SECTION 1
DESCRIPTION
1.1 INTRODUCTION
This manual contains Operating, Service, and
Maintenance Instructions for Gen 4 and Gen 5 Split
System Air Conditioning and Heating equipment
furnished by Mobile Climate Control. Additional
support manuals are listed in Table 1-1.
A Split System normally includes an Evaporator(s), a
Condenser(s) a Compressor(s) and interconnecting
refrigerant hoses, fittings, and electrical harnesses
and controls. A listing of the evaporator and
condenser models, along with specific data for each,
is provided in the component data that follows.
Specific systems may vary, this manual does not
cover all combinations, variations, and applications,
it does set up standards from which processes can be
measured. Contact Mobile Climate Control
Technical Service Hot-Line for additional assistance
(800-450-2211).
1.2 WHAT IS AIR CONDITIONING
Air Conditioning is the cooling, heating,
dehumidification, and filtration of the air located
within the passenger compartment of a vehicle.
1.3 MODEL AND SERIAL NUMBER TAGS
In order to identify the air conditioning components
you have, you will need to know the model number
and serial number. All Mobile Climate Control
evaporators, condensers and compressors have a
model/serial number tag or PID decal located on the
assembly. See Figure 1-1 for all skirt mounted
condenser data tag locations, Figure 1-2 for GEN 4
evaporator data tag location, Figure 1-3 for GEN 5
evaporator data tag locations, Figure 1-4 &
Figure 1-5 for In-Wall data tag locations, Figure 1-7
for KR-2 & KR-3 PID locations and Figure 1-6 for
the CM-7 & CM-11 rooftop condensers data tag
location. The CM-7 and CM-11 rooftop condensers
are no longer available from MCC.
NOTE
The EM-9 evaporator data tag is located on
the side of the evaporator assembly, not
between the blower assemblies (See
Figure 1-2).
Knowing these locations and the information on the
data tags will aid you in identifying the correct service
procedures.
1.3.1 PID Data Tag (Decal)
All KR2, KR3 & KR4 Rooftop Condensers have
PID Decals instead of the standard Model/Serail tag.
These tags will list the following:
a. System Model No. (Example - 68KR4-101-2)
b. Serial No.
c. P.I.D. (Example - KR4C00032)
d. Refrigerant (Example - R134a)
e. Voltage (Example - 13.5 VDC)
f. Amps (Example - 25A)
g. Unit Weight (Example - 186 lbs.)
Table 1-1 Additional Support Manuals
MANUAL NUMBER EQUIPMENT COVERED TYPE OF MANUAL
T-299PL Split Systems Parts List
T-311 Split Systems Installation Procedures

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©2012 Mobile Climate Control T-299 Rev. 08/2012
Figure 1-1 Condenser Model CM2/3 - Serial Number Location
EM-9 Location
Figure 1-2 GEN 4 Evaporator Model - Serial Number Location
Figure 1-3 GEN 5 Evaporator Model (All) - Serial Number Location

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©2012 Mobile Climate Control T-299 Rev. 08/2012
5
2
Figure 1-4 GEN 4, IW-2 & IW-7 - Serial Number Location
Figure 1-5 GEN 4, IW-1 - Serial Number Location

1--4
©2012 Mobile Climate Control T-299 Rev. 08/2012
Obsolete Tag
Figure 1-6 CM-7/11 Rooftop Condensers (No Longer Offered) - Serial Number Location
Figure 1-7 KR-2/KR-3 Rooftop Condensers - Serial Number/PID Location
01- 22- 07
Figure 1-8 System Requirements Label

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©2012 Mobile Climate Control T-299 Rev. 08/2012
1.4 SYSTEM REQUIREMENTS LABEL
The system requirements label is conveniently
located within the vehicle's engine compartment.
This label, when properly completed by the installer,
will give the servicing technician the refrigerant and
oil charge(s), evaporator(s), condenser(s), and
compressor(s) serial numbers, the drive belt(s)
number, mount kit number, the date of installation
and the installer (See Figure 1-8).
1.5 SYSTEM DESIGNATIONS
Tie-In System - Is an MCC evaporator and
condenser connected to an existing OEM
compressor and dash evaporator. The OEM radiator
condenser is normally removed.
NOTE
You may encounter installations where the
OEM radiator style condenser is used as the
Tie-In condenser. Call Mobile Climate
Control Technical Service Hot-Line
(800-450-2211) for assistance, as this is not a
recommended Mobile Climate Control Air
Conditioning application.
Max System - An MCC system installed along with
an existing OEM system. The systems operate
independent of each other.
Stand-Alone (Standard) System - All MCC
components installed on a vehicle. These can be
either single or dual compressor systems.
IW (In-Wall) System - An MCC evaporator
installed in the front and/or rear of the vehicle. This
type evaporator is installed between the inside &
outside walls of the vehicle.
1.6 SYSTEM COMPONENTS
Return Air Thermostat/Sensor - The system may
be supplied with a thermostat or thermistor Both of
these devices are temperature sensitive components
which when activated, signals the Electro-Magnetic
Clutch to engage/disengage. The return air
thermostat is normally located in the drivers control
panel while the return air thermister is normally
located in the evaporator assembly.
Electro-Magnetic clutch - The Electro-Magnetic
clutch controls the operation of the compressor.
When engaged, the compressor circulates refrigerant
and provides cooling (See Figure 1-9).
Expansion/Block Valve - Meters the refrigerant
flow into the evaporator coil. The majority of the
Gen 4 (Excel) and all Gen 5 systems use a
nonadjustable block valve with an 8°Fsuperheat
setting, which is preset at the factory. Ifyou feelthere
is a problem with the block valve, do not attempt to
adjust the valve, replace it.
NOTE
In the event you encounter a Gen 1, Gen 2,
or Gen 3 system with an externally equalized
expansion valve and/or a system with
refrigerant R12, contact MCC's Technical
Service Hot Line (800-450-2211) for
assistance.
Evaporator - The evaporator is located in the
interior of the vehicle. Its primary function is to
transfer heat contained in the passenger
compartment air, into the refrigerant, which is
circulated by the compressor, through the
evaporator coil. During this process the air is also
filtered and dehumidified.
Resistor - Resistors are used to control the speeds of
the permanent magnet evaporator blower motors.
Compressor - The compressor is a belt driven,
high-pressure pump, which circulates the refrigerant
through the evaporator and condenser . The
operation of the compressor is controlled by the
Electro-Magnetic clutch.
Condenser - The condenser is normally located in
the skirt or on the roof of the vehicle. Its primary
function is to reject heat, which was transferred to
the refrigerant by the evaporator from the passenger
compartment of the vehicle.
Filter-Dryer - The filter-dryer removes moisture
and particulate matter from the refrigerant.
Receiver-Dryer - The receiver-dryer removes
moisture and particulate matter from the refrigerant.
The receiver-drier also stores a small amount of
liquid refrigerant.
Pressure Switches - Thesystemsusehighandlow
pressure switches wired in series to control the
power circuit of the compressor clutch relay. If
either pressure switch opens, interrupting the circuit
to the clutch relay, the operation of the compressor
will stop. When conditions return to normal the
switch will automatically reset and the compressor
will resume operating. The switches are
non-adjustable.

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©2012 Mobile Climate Control T-299 Rev. 08/2012
Freeze-Up Thermostat - Mobile Climate Control
systems use a freeze thermostat (freeze stat) wired in
series with the system pressure switches to control
the operation of the compressor clutch. Freeze-up
thermostats are used to prevent ice from forming on
the evaporator coil, which is an indication that liquid
refrigerat is getting back to the compressor.
Refrigerant - A refrigerant is a material that is used
to move heat from the passenger compartment to
the outside air. It is a substance that gives up heat by
condensing at high temperature and pressures and
absorbs heat by evaporating at low temperatures and
pressures. The heat transfer properties exhibited
when refrigerant changes state is the foundation of
the refrigerant cycle. Most MCC systems use R134a.
1
10
9
8
7
6
5
4
3
2
5
11
12
1 Compressor
2 Electro-Magnetic Clutch
3DischargeLine
4 Condenser
5 Filter-Dryer or Receiver-Drier
6 Liquid Line
7 Evaporator
8 Block Valve (TXV)
9 Freeze stat-(Coil freeze-up thermostat)
10 Suction Line
11 Suction Access Valve
12 Discharge Access Valve
Figure 1-9 Component Location Diagram
1.7 REFRIGERATION SYSTEM COMPONENT
SPECIFICATIONS
a. EXPANSION/BLOCK VALVE:
Superheat Setting: 8°F
b. PRESSURE SWITCHES:
High Pressure Switch: Normally closed, open on
pressure rise.
Cut-out at 400 psig - Cut-in at 300 psig.(±5%)
Low Pressure Switch: Normally closed, open on
pressure drop.
Cut-in at 25 psig. - Cut-out at 10 psig (±5%)

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©2012 Mobile Climate Control T-299 Rev. 08/2012
c. FREEZE-UP THERMOSTAT:
GEN 4 Series Freeze-Up Thermostat: Cut-out at 26°
F, ±1.5°F. Cut-in at 34°F, ±1.5°F. Pre-set at
factory (Adjustable). Turn counterclockwise to end -
then 1/4 turn clockwise for original factory setting.
GEN 5 Series Freeze-Up Thermostat: Cut-out at
30.5°F, ±1.5°F. Cut-in at 45°F, ±1.5°F. Pre-set at
the factory (Non-adjustable).
d. RETURN AIR THERMOSTAT/SENSOR
Return Air Thermostat: Adjustable range from 55°F
to 85°F. Normal remote (drivers location) setting is
55°Fwitha±5°F differential.
Return Air Sensor (Total Control): Temperature
range 60°Fto80°F.
e. EVAPORATOR MOTORS
Gen 4 Series: Double shafted 12 VDC (13.5 VDC
Nominal), permanent magnet, motor/blower
assemblies.
Full Load Amps: Refer to Table 3-1
Volts DC Maximum: 15.1 VDC
Volts DC Minimum: 10.8 VDC
RPM: 2600 @ zero static
Gen 5 Series: Single shafted 12 VDC continuous
duty motors.
Full Load Amps: 30 Amps @ 2900 RPM @ 12.5
VDC
Locked Rotor Amps: 80 Amps
Volts DC Maximum: 16 VDC
Volts DC Minimum: 4 VDC
f. CONDENSER MOTORS
Rooftop:
CM-7 and CM-11: Single shafted 12 VDC (12.5
Nominal) continuous duty motors (barrel type) to
be used with Rooftop Condensers.
Full Load Amps: 30 Amps @ 2900 RPM @ 12.5
VDC
Locked Rotor Amps: 80 Amps
Volts DC Maximum: 16 VDC
Volts DC Minimum: 4 VDC
KR-2 and KR-3: Fan-Motor Assembly. Single
shafted 12 VDC (12.5 Nominal) continuous duty
motors.
Full Load Amps: 7 Amps @ 2100 RPM @ 12.5
VDC
Locked Rotor Amps: 40 Amps
Volts DC Maximum: 13.5 VDC
Volts DC Minimum: 5 VDC
KR-4: Single shafted, permanent magnet, 12 VDC
(12.5 Nominal) continuous duty, single speed
motors.
Full Load Amps: 7 Amps @ 1900 RPM @ 12.5
VDC
Locked Rotor Amps: 30 Amps
Volts DC Maximum: 16 VDC
Volts DC Minimum: 4 VDC
Skirt Mounted: Permanent magnetic,single speed
motor (12VDC nominal) and fan combination
(pancake style) 5 blades.
Full Load Amps: 7 Amps @ 2100 RPM @ 12.5
VDC
Locked Rotor Amps: 40 Amps @ 13.5VDC
Volts DC Maximum: 13.5 VDC
Volts DC Minimum: 5 VDC
Skirt Mounted (”Vector” Fan): Permanent
magnetic,single speed motor (12VDC nominal)
and fan combination (pancake style) 10 blades.
Full Load Amps: 6.8 Amps @ 2350 RPM @ 12.5
VDC
Locked Rotor Amps: 25.4 Amps @ 13.5VDC
Volts DC Maximum: 13.5 VDC
Volts DC Minimum: 5 VDC
g. COMPRESSORS
Mobile Climate Control uses a variety of
compressors properly sized and suited for split
system applications. Their cubic inch
displacement (c.i.d.) ranges from a 10 cubic inch
TM-16 to the 19.1 cubic inch TM-31. Applications
include rear and front engine mounted.
Compressor Clutch coils typically draw 2 to 3
Amps. A compressor must always be replaced
with a compressor of the same style and capacity.
1.8 COOLING CYCLE
The unit operates as a vapor compression system
using R-134a as the refrigerant (see Figure 1-10 ).
The compressor raises the pressure and the
temperature of the refrigerant vapor and forces it
thru the discharge lines into the condenser tubes.
The condenser fan circulates surrounding air (which
is at a temperature lower than the refrigerant) over
the outside of the condenser tubes. Heat transfer is
established from the refrigerant (inside the tubes) to
the condenser air (flowing over the tubes). The
condenser tubes have fins designed to improve the
transfer of heat from the refrigerant gas to the air;
this removal of heat causes the refrigerant to liquefy,
thus liquid refrigerantleaves thecondenser and flows
to the filter-drier. The filter-drier contains an
absorbent that keeps the refrigerant clean and dry.

1--8
©2012 Mobile Climate Control T-299 Rev. 08/2012
NOTE
The new style micro-channel condensers are
fitted with receiver-driers instead of
filter-driers. The receiver-drier performs the
same function as a filter-drier and it also
stores liquid refrigerant.
From the filter-drier/receiver-drier, the liquid
refrigerant then flows to the block type expansion
valve. The expansion valve reduces pressure and
temperature of the liquid and meters the flow of
liquid refrigerant to the evaporator to obtain
maximum use of the evaporator heat transfer
surface.
The low pressure, low temperature liquid that flows
into the evaporator tubes is colder than the air that is
circulated over the evaporator tubes by the
evaporator fans. Heat transfer isestablished from the
evaporator air (flowing over the tubes) to the
refrigerant (flowing inside the tubes). The
evaporator tubes have fins to increase heat transfer
from the air to the refrigerant; therefore the cooler
air is circulated to the interior of the vehicle.
The transfer of heat from the air to the low
temperature liquid refrigerant in the evaporator
causes the liquid to vaporize. This low temperature,
low pressure vapor refrigerant then continues
through the suction line and returns to the
compressor where the cycle repeats.

1--9
©2012 Mobile Climate Control T-299 Rev. 08/2012
TXV
EVAPORATOR COIL
CONDENSER COIL
FILTER DRYER
OR
RECEIVER DRIER
SIGHT GLASS
SUCTION ACCESS PORT
(GEN 5
Location)
HPS
LPS
DISCHARGE
ACCESS PORT
COMPRESSOR
LPS
(GEN 5 Location)
(GEN 4
Location)
DISCHARGE LINE
SUCTION LINE
LIQUID LINE
DISCHARGE LINE
LIQUID LINE
SUCTION LINE
EVAPORATOR ASSEMBLY
CONDENSER ASSEMBLY
NOTE:
MICRO--CHANNEL
CONDENSER HPS IS LO-
CATED ON RECEIVER--DRIER
Figure 1-10 Air Conditioning Refrigerant Flow Diagram - Small Split System

1--10
©2012 Mobile Climate Control T-299 Rev. 08/2012
1.9 HEATING CYCLE (If Applicable)
The optional heating circuit component furnished
by Mobile Climate Control is the side or rear
mounted evaporator heater core. Components
furnished by the vehicle manufacturer include
coolant (glycol solution), pumps, and a hot water
shut-offvalve(SeeFigure1-11).
Engine coolant is circulated through the heating
circuit by the engine and/or auxiliary water pump.
When the heat valve is opened, engine coolant flows
through the heater coil. Heat is transferred from the
glycol flowing in the tubes to the air flowing over the
tubes. The heater tubes have aluminum fins to
increase heat transfer from the glycol to the air.
*AUXILIARY
HEATER
*ENGINE
*AUXILIARY
HEATER PUMP
*ENGINE
WATER PUMP
*INDICATES COMPONENTS FURNISHED
BY THE VEHICLE MANUFACTURER
*HAND VALVE
AIR BLEED
VALVE
EVAPORATOR HEATER CORE
EVAPORATOR
Figure 1-11 Heating System Flow Diagram (Typical)

2--1
©2012 Mobile Climate Control T-299 Rev. 08/2012
SECTION 2
OPERATION
2.1 OPERATING INSTRUCTIONS
Before attempting to operate the system, power
must be available from the vehicle battery. If the
engine is not running, start the engine.
The system may be supplied with Manual Controls
(see Figure 2-1 & Figure 2-3 ) or the Mobile Climate
Control Total Control (see Figure 2-5).
Refer to the Sections 2.2 & 2.3 for manual control
operating instructions or Section 2.5 for Total
Control operating instructions.
2.2 MANUAL CONTROLS
Mobile Climate Control systems are manually
operated by a Drivers Control Panel (See Figure 2-1)
wired into an Electrical Control Panel (See
Figure 2-2).
2.2.1 Driver's Control Panel
The Drivers Control Panel (See Figure 2-1), consists
of an evaporator fan speed switch (three speed or
variable) and an adjustable thermostat. The drivers
control panel is normally located within easy reach of
the driver. On larger bus applications there could be
two (2) separate air conditioning system driver
control panels. One for each system.
There will be some applications where the switch
mounting plate, thermostat and fan speed switch are
mounted in the drivers area without the control
panel housing.
On some applications the vehicle manufacturer
(OEM) will supply different type controls for the air
conditioning system. Refer to OEM technical
manual for operating instructions.
2.2.2 Fan Speed Switch (three speed or variable)
Three Speed - The standard fan speed switch has
four settings, Off (0), Low (1), Medium (2), and High
(3) speed operation. This switch controls the
operation of the system and the evaporator
blower(s) by energizing the appropriate circuits and
relays located on the electrical control panel. See
Figure 2-2.
Variable Speed - Certain applications may be fitted
with a variable speed control switch instead of the
standard three speed switch. This switch controls the
speed of the evaporator motors by varying the
supply voltage.
2.2.3 Thermostat Control
The thermostat controls the temperature within the
passenger compartment by switching system
components on and off.
1
234
5
1 Control Panel Housing
2 Nameplate (Switch Mounting)
3 Thermostat Control Switch
4 Fan Speed Switch (3 Speed or Variable)
5 AmbientAirSensor(Thermostat)
Figure 2-1 Drivers Control Panel
2.2.4 Electrical Control Panel
The electrical control panel contains relays and
circuit breakers used for system control.
12345
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 2-2 Electrical Panel (Typical)