MCC 50-2104 Operation manual

OPERATION/SERVICE MANUAL
for
MCC Eco Xcel SERIES
T-367 Manual
REV. 05/2015
T-367
©2015 Mobile Climate Control

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©2015 Mobile Climate Control T-367Rev . 05/2015
TABLE OF CONTENTS
SAFETY SUMMARY Safety--1.......................................................................
DESCRIPTION 1--1...............................................................................
1.1 INTRODUCTION 1--1.....................................................................
1.2 GENERAL DESCRIPTION 1--2.............................................................
1.2.1 Rooftop Unit 1--2......................................................................
1.2.2 Condensing Section 1--2...............................................................
1.2.3 Evaporator Sections 1--3...............................................................
1.2.4 MCC Microprocessor 1--3..............................................................
1.3 REFRIGERATION SYSTEM COMPONENT SPECIFICATIONS 1--3.............................
1.4 ELECTRICAL SPECIFICATIONS -- MOTORS 1--3............................................
1.5 SAFETY DEVICES 1--4...................................................................
1.6 AIR CONDITIONING REFRIGERATION CYCLE 1--5..........................................
1.7 HEATING CYCLE 1--5....................................................................
OPERATION of MCC XCEL DRIVER DISPLAY 2--1...................................................
2.1 General Description 2--1...................................................................
2.2 STARTING, STOPPING AND OPERATING INSTRUCTIONS 2--1..............................
2.2.1 Starting 2--1..........................................................................
2.3 SEQUENCE OF OPERATION 2--2..........................................................
2.3.1 Function of Keys when “Engine On” and controller active: 2--2...............................
2.4 BASIC OPERATING INSTRUCTIONS 2--3..................................................
2.4.1 Display 2--3..........................................................................
2.4.2 Interior Set Point Temperature Control 2--3...............................................
2.4.3 Blower Speed Setting 2--3..............................................................
2.4.4 Mode Selection Descriptions 2--3........................................................
2.4.5 Capacity Control “Ladder” Diagrams 2--3.................................................
2.4.6 Display Settings 2--5...................................................................
2.4.7 HVAC Information Screens 2--6.........................................................
2.4.8 HVAC Diagnostics Screens 2--7.........................................................
2.4.9 HVAC Alarm Description 2--8...........................................................
2.5 MCC Eco NG Coolview 2--9...............................................................
2.5.1 Starting the MCC Coolview Application 2--10...............................................
2.5.2 Coolview Screen Layout 2--11...........................................................
2.5.3 Eco NG Display Pin out Description 2--16..................................................
2.5.4 Eco NG Controller Pin out Description 2--17...............................................
TROUBLESHOOTING 3--1.........................................................................
3.1 System Will Not Cool 3--1..............................................................
3.2 System Runs But Has Insufficient Cooling 3--1............................................
3.3 Abnormal Pressures 3--1...............................................................
3.4 Abnormal Noise Or Vibrations 3--1.......................................................
3.5 No Evaporator Air Flow Or Restricted Air Flow 3--2........................................
3.6 Expansion Valve Malfunction 3--2........................................................
3.7 Heating Malfunction 3--2...............................................................
SERVICE 4-1....................................................................................
4.1 MAINTENANCE SCHEDULE 4-1...........................................................

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©2015 Mobile Climate Control T-367Rev . 05/2015
4.2 OPENING TOP COVER (EVAPORATORS) 4-2..............................................
4.3 REMOVING TOP COVERS (CONDENSER) 4-2.............................................
4.4 SUCTION AND DISCHARGE SERVICE VALVES 4-3.........................................
4.4.1 Installing R--134a Manifold Guage Set 4-4...............................................
4.4.2 SYSTEM PUMP DOWN FOR LOW SIDE REPAIR 4-6....................................
4.4.3. Removing Entire System Charge 4-7....................................................
4.5 REFRIGERANT LEAK CHECK 4-7.........................................................
4.6 EVACUATION AND DEHYDRATION 4-7....................................................
4.6.1 General 4-7..........................................................................
4.6.2 Preparation 4-7.......................................................................
4.6.3 Procedure for Evacuation and Dehydrating System (One Time Evacuation) 4-8...............
4.6.4 Procedure for Evacuation and Dehydrating System (Triple Evacuation) 4-8...................
4.7 CHECKING AND ADDING REFRIGERANT TO SYSTEM 4-8..................................
4.7.1 Checking Refrigerant Charge By Pressures 4-8...........................................
4.7.2 Checking Refrigerant Charge By Receiver Sight Glasses 4-9...............................
4.7.3 Adding Full Charge 4-9................................................................
4.7.4 Adding Partial Charge 4-11.............................................................
4.8 CHECKING SYSTEM FOR NON--CONDENSIBLES 4-11.......................................
4.9 CHECKING AND REPLACING HIGH OR LOW PRESSURE SWITCH 4-11.......................
4.10 FILTER--DRIER 4-12......................................................................
4.10.1 To Check Filter--Drier 4-12...............................................................
4.10.2 To Replace Filter--Drier 4-12.............................................................
4.11 SERVICING THE LIQUID LINE SERVICE VALVE 4-12.........................................
4.11.1 Coil Replacement 4-13.................................................................
4.11.2 Internal Part Replacement 4-13..........................................................
4.11.3 Replace Entire LLS Valve 4-13...........................................................
4.12 THERMOSTATIC EXPANSION VALVE 4-14..................................................
4.12.1 Valve Replacement 4-14................................................................
4.12.2 Superheat Measurement 4-14...........................................................
4.13 REPLACING EVAPORATOR RETURN AIR FILTERS 4-15.....................................
4.14 COMPRESSOR MAINTENANCE 4-16.......................................................
4.14.1 Shaft Seal Reservoir 4-16...............................................................
4.14.2 Refrigerant Removal From An Inoperative Compressor. 4-16................................
4.14.3 Pump Down An Operable Compressor For Repair 4-16.....................................
4.14.4 Removing the Compressor 4-17.........................................................
4.14.5 Transferring Compressor Clutch 4-18.....................................................
4.14.6 Compressor Oil Level 4-19..............................................................
4.14.7 Checking Unloader Operation 4-19.......................................................
4.15 TEMPERATURE SENSOR CHECKOUT 4-21.................................................
4.16 PRESSURE TRANSDUCER CHECKOUT 4-21...............................................
4.17 REPLACING SENSORS AND TRANSDUCERS 4-21..........................................
ELECTRICAL 5--1................................................................................
5.1 INTRODUCTION 5--1.....................................................................

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©2015 Mobile Climate Control T-367Rev . 05/2015
LIST OF TABLES
Table 1--1 Models 1--1.............................................................................
Table 1--2 Additional Support Manuals 1--1............................................................
Table 3--1 General System Troubleshooting Procedures 3--1............................................
Table 4-1 Temperature Sensor Resistance 4-21........................................................
Table 4-2 Pressure Transducer Voltage 4-22...........................................................
Table 4-3 R--134a Temperature -- Pressure Chart 4-23..................................................
LIST OF FIGURES
Figure1--1RooftopUnit(EcoXcel) 1--2.............................................................
Figure 1--2 Refrigerant Flow Diagram 1--6...........................................................
Figure 1--3 Heat Flow Diagram 1--7.................................................................
Figure 2-1 Driver Display Module-- Control Layout 2--1................................................
Figure 2-2 Driver Display Module-- Display Layout 2--2................................................
Figure 2-3 Capacity Control Ladder Diagrams 2--4....................................................
Figure 2-4 HVAC DISPLAY SETTINGS 2--5..........................................................
Figure 2-5 HVAC INFORMATION SCREENS 2--6....................................................
Figure 2-6 HVAC DIAGNOSTIC SCREENS 2--7......................................................
Figure 2-7 MCC Eco NG Display Alarms 2--8........................................................
Figure 2-8 MCC Eco NG Coolview (Example Screenshot) 2--9.........................................
Figure 2-9 MCC Eco NG Coolview (VIEW Tab) 2--10...................................................
Figure 2-10 MCC Eco NG Coolview Inputs and Mode (VIEW Tab) 2--11..................................
Figure 2-11 MCC Eco NG Coolview Outputs (VIEW Tab) 2--12..........................................
Figure 2-12 MCC Eco NG Coolview Error List (ERROR Tab) 2--12.......................................
Figure 2-13 MCC Eco NG Coolview Statistics (HOURS Tab) 2--13.......................................
Figure 2-14 MCC Eco NG Coolview Simulation Mode 2--14.............................................
Figure 2-15 MCC Eco NG Coolview Data Logger 2--15.................................................
Figure 2-16 MCC Eco NG Display Pinout 2--16........................................................
Figure 2-17 MCC Eco NG ControllerPinout 2--17......................................................
Figure 4-1 Opening Top Cover (Evaporator) 4-2......................................................
Figure 4-2 Removing Top Covers (Condenser) 4-2...................................................
Figure 4-3 Suction or Discharge Service Valve 4-3...................................................
Figure 4-4 Manifold Gauge Set (R--134a) 4-4........................................................
Figure 4-5 Service Connections 4-5................................................................
Figure 4-6 Rule of Thumb 4-8.....................................................................
Figure 4-7 Service Connections 4-10................................................................
Figure 4-8 Checking High Pressure Switch 4-11.......................................................
Figure 4-9 Filter--Drier Removal 4-12................................................................
Figure 4-10 Liquid Line Solenoid Valve 4-13..........................................................
Figure 4-11 Thermostatic Expansion Valve Bulb and Thermocouple 4-14.................................
Figure 4-12. Compressor Service Connections 4-16...................................................
Figure 4-13. Compressor Service Connections 4-16...................................................
Figure 4-14. Compressors 4-17.....................................................................

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©2015 Mobile Climate Control T-367Rev . 05/2015
LIST OF FIGURES (Continued)
Figure 4-15. Removing Bypass Piston Plug 4-17......................................................
Figure 4-16. Compressor Clutch 4-18................................................................
Figure 4-17 Transducer Terminal Location 4-21.......................................................
Figure 5--1 Schematic 50--2104S 5--2...............................................................
Figure 5--2 Schematic T50--2112S 5--3..............................................................

Safety--1
©2015 Mobile Climate Control T-367 Rev. 05/2015
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
and maintenance of the equipment covered herein. 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 safety glasses.
Keep hands, clothing and tools clear of the evaporator and condenser fans.
No work should be performed on the unit until all start-stop switches are placed in the OFF position, and
power supply is disconnected.
Always work in pairs. Never work on the equipment alone.
In case of severe vibration or unusual noise, stop the unit and investigate.
MAINTENANCE PRECAUTIONS
Beware of unannounced starting of the evaporator and condenser fans. Do not open the unit cover before
turning power off.
Be sure power is turned off before working on motors, controllers, solenoid valves and electrical controls.
Tag circuit breaker and power supply to prevent accidental energizing of circuit.
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 unit, disconnect all wire harness connectors from the modules in
the control box. Do not remove wire harness from the modules unless you are grounded to the unit frame
with a static-safe wrist strap.
In case of electrical fire, open circuit switch and extinguish with CO2(never use water).

Safety--2
©2015 Mobile Climate Control T-367 Rev. 05/2015
SPECIFIC WARNINGS AND CAUTIONS
WARNING
Use of an electro-magnetic valve as a means of positive shutoff for service is not recom
mended for safety, or good service practice.
WARNING
Be sure to observe warnings listed in the safety summary in the front of this manual be
fore performing maintenance on the hvac system
WARNING
Read the entire procedure before beginning work. Park the vehicle on a level surface,
with parking brake applied. Turn main electrical disconnect switch to the off position.
WARNING
Do Not Use A Nitrogen Cylinder Without A Pressure Regulator
WARNING
Do Not Use Oxygen In Or Near A Refrigeration System As An Explosion May Occur.
WARNING
The Filter-drier May Contain Liquid Refrigerant. Slowly Loosen The Connecting Nuts And Avoid Con
tact With Exposed Skin Or Eyes.
CAUTION
The 50-2104 Rooftop Systems have R134a service port couplings installed on the compressor and on the unit
piping.
CAUTION
To prevent trapping liquid refrigerant in the manifold gauge set be sure set is brought to suction pres
sure before disconnecting.

1--1
©2015 Mobile Climate Control T-367Rev. 05/2015
SECTION 1
DESCRIPTION
1.1 INTRODUCTION
This manual contains Operating Instructions,
Service Instructions and Electrical Data for the
EcoXcel Model Air Conditioning and Heating
equipment furnished by Mobile Climate Control as
showninTable1-1.
The system is identified with a Model/Serial number
tag located inside the evaporator section, on the rear
bulkhead wall of the assembly. Example is shown in
Figure 1-1.
Models consists of a Rooftop unit containing the
condensing section, the evaporator sections and
engine compartment mounted compressor. To
complete the system, the air conditioning and
heating equipment interfaces, electrical cabling,
refrigerant piping, engine coolant piping (for
heating), duct work and other components
furnished by Mobile Climate Control and/or the bus
manufacturer.
Additional support manuals are shown in Table 1-2.
Operation of the unit is controlled automatically by a
Mobile Climate Control Microprocessor based
controller. The controls maintain the vehicle's
interior temperature at the desired set point.
Table 1-1 Models
Model Voltage Controller With Heat Single Loop W/Covers
50-2104 24 VDC MCC EcoTemp NG
Microprocessor Yes X X
T50-2112 24 VDC MCC EcoTemp NG
Microprocessor Yes X X
Table 1-2 Additional Support Manuals
MANUAL NUMBER EQUIPMENT COVERED TYPE OF MANUAL
T-367PL Eco Xcel Models Service Replacement Parts List

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©2015 Mobile Climate Control T-367Rev. 05/2015
1.2 GENERAL DESCRIPTION
1.2.1 Rooftop Unit
The rooftop unit includes the condenser section and the evaporator sections (See Figure 1-1).
Model/Serial Number Plate
Interior Location
EVAPORATOR SECTION
Evaporator Section
Condenser Section
Figure 1-1 Rooftop Unit (Eco Xcel)
1.2.2 Condensing Section
The condensing section includes 2 micro-channel
condenser coils, four (4) fan and motor assemblies
and receiver tank assembly with sight glasses,
moisture indicator and fusible plug
The condenser coils provide heat transfer surface for
condensing refrigerant gas at a high temperature and
pressure into a liquid at high temperature and
pressure. The condenser fans circulate ambient air
across the outside of the condenser tubes at a
temperature lower than refrigerant circulating inside
the tubes; this results in condensation of the
refrigerant into a liquid. The receiver tank is also
equipped with a pressure relief valve (fusible plug)
which protects the system from unsafe high pressure
conditions. The filter-drier, located in the evaporator
section, removes moisture and debris from the liquid
refrigerant before it enters the thermostatic
expansion valve in the evaporator assembly.
a. Condenser fan operation
Low Speed ON: 150 psig (10.31 bar)
Low Speed OFF: 120 psig (8.27 bar)
High Speed ON: 225 psig (15.51 bar)
High Speed OFF: 165 psig (11.38 bar)

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©2015 Mobile Climate Control T-367Rev. 05/2015
1.2.3 Evaporator Sections
The evaporator section includes the evaporator coil,
two (2) blower motor assemblies, thermostatic
expansion valve, heater coil assembly, heater valve,
filter/drier, service valves and condensate drain
connections.
The evaporator coil provides heat transfer surface
for transferring heat from air circulating over the
outside of the coil to refrigerant circulating inside the
tubes; thus providing cooling. The heating coils
provide a heat transfer surface for transferring heat
from engine coolant water circulating inside the
tubes to air circulating over the outside surface of the
tubes, thus providing heating. The fans circulate the
air over the coils. The air filters (OEM supplied)
remove dirt particles from the air before it passes
over the coils. The thermostatic expansion valve
meters the flow of refrigerant entering the
evaporator coils. The heat valve controls the flow of
engine coolant to the heating coils upon receipt of a
signal from the controller. The condensate drain
connections provide a means for connecting tubing
for disposing of condensate collected on the
evaporator coils during cooling operation.
1.2.4 MCC Microprocessor
The MCC controller maintains desired temperature
set point by controlling compressor capacity, fan
speeds and heat valve operation. Refer to Section 2,
for operational sequences.
1.3 REFRIGERATION SYSTEM COMPONENT SPECIFI-
CATIONS
a.System Capacity: Cooling - 120,000 Btu/Hr (35 kW)
Heating - 126,000 Btu/Hr (37 kW)
b. Refrigerant Charge R-134a (Approximate)
NOTE
Refrigerant charge will depend on hose
lengths and diameters; or if there is an In-
Dash unit (front evaporator). The following
should only be used as a guideline.
50-2104 with 05G Compressor
13 ± 0.5 Pounds (5.9 ± 0.23 kg)
c. Compressor
Compressor 05G
No. Of Cylinders 6
Weight, (Dry) With Clutch 145 Lbs. (66 kg)
Oil Charge 5.5 pints
(2.6 liters)
d. Thermostatic Expansion Valve:
7 Ton Capacity- Adjustable
e. High Pressure Switch (HPS)
Normally Closed
Opens at: 360 ±10 psig (24.82 ±0.68bar)
Closes at: 285 ±15 psig (19.65 ±0.68bar)
f. Low Pressure Switch (LPS)
Normally Open
Opens at: 6 ±3psig (0.41 ±0.20 bar)
Closes at: 25 ±3psig(1.7±0.20 bar)
g. Water Temperature Switch (WTS) (If Equipped)
[Bus Manufacturer Supplied - Suggested close on tempera
ture rise at 105°F(41°C)]
1.4 ELECTRICAL SPECIFICATIONS - MOTORS
a. Evaporator Blower/Motor
Evaporator Motor Brushless
24 VDC
Full Load Amps (FLA) ~25
Bearing Lubrication Factory Lubricated
(additional grease not required)
b. Condenser Fan Motor
Condenser Motor Brushless
24 VDC
Full Load Amps (FLA) ~7
Bearing Lubrication Factory Lubricated
(additional grease not required)
c. Temperature Sensors (All)
Input Range: -40 to 167°F(-40to75°C)
Output: NTC 10K ohms at 77°F(25°C)
d. Ambient Sensor (Controls Compressor Outputs)
Opens at: 43°F(6.1°C)
Closes at: 47°F(8.3°C)