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MCC 68AC430-100 Operation & Service Manual

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T-353
Manual
OPERATION/SERVICE
for
68AC430-100
T-353
REV. 01/2013
© 2012 Mobile Climate Control

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Summary of Contents for MCC 68AC430-100

  • Page 1 T-353 Manual OPERATION/SERVICE 68AC430-100 T-353 REV. 01/2013 © 2012 Mobile Climate Control...

  • Page 2: Table Of Contents

    TABLE OF CONTENTS SAFETY SUMMARY ............. . . Safety-1 DESCRIPTION .
  • Page 3 TABLE OF CONTENTS (Continued) SERVICE ............... . MAINTENANCE SCHEDULE .
  • Page 4 LIST OF FIGURES Figure 1-1 AC430 Rooftop Unit ........... . Figure 1-2 Refrigerant/Heat Flow Diagram, AC430 .

  • Page 5: Safety Summary

    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.
  • Page 6 SPECIFIC WARNINGS AND CAUTIONS WARNING Be sure to observe warnings listed in the safety summary in the front of this manual before 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.

  • Page 7: Description

    12 VDC BT324 4.6M 68AC430-100-6 12 VDC BT324 7.8M 68AC430-100-7 12 VDC BT324 7.8M 68AC430-100-8 * 12 VDC BT324 7.8M Table 1-2 Additional Support Manuals MANUAL NUMBER EQUIPMENT COVERED TYPE OF MANUAL T-353PL 68AC-430-100 Service Parts List * Denotes Special Packaging 1--1 ©...

  • Page 8: General Description

    1.2 GENERAL DESCRIPTION 1.2.1 Rooftop Unit The rooftop unit includes the condenser section and the evaporator section (See Figure 1-1). Evaporator Section Condenser Section Figure 1-1 AC430 Rooftop Unit 1.2.2 Condensing Section 1.2.3 Evaporator Section The evaporator section includes the evaporator coils, The condensing section includes the condenser two (2) single-shafted blower/motor assemblies, two coils, two (2)fan and motor assemblies, receiver,...

  • Page 9: Bt-324 Microprocessor

    1.2.4 BT-324 Microprocessor 1.4 ELECTRICAL SPECIFICATIONS - MOTORS This BT-324 controller has three (3) modes, Auto, a. Evaporator Blower/Motor Vent (Cycle clutch type) and Heat. Brushless Evaporator Motor In the auto mode the compressor is energized while 12 VDC the evaporator and condenser fans are operated to Horsepower (kW) .375 (.28) provide refrigeration as required.

  • Page 10: Air Conditioning Refrigeration Cycle

    Low Pressure Switch (LPS) filter-drier where a desiccant keeps the refrigerant clean and dry. The low pressure switch is installed in the evaporator From the filter-drier, the liquid refrigerant then flows section and opens on a pressure drop to shut down through the liquid line to the sight-glass and then to the system when a low pressure condition occurs.

  • Page 11: Figure 1-2 Refrigerant/Heat Flow Diagram, Ac430

    Discharge Liquid Suction Coolant CONDENSER EVAPORATOR Figure 1-2 Refrigerant/Heat Flow Diagram, AC430 Thermal Expansion Valve Evaporator Coil Liquid Line Sight Glass Compressor Fusible Plug Service Valve Dash Air Liquid Line Condenser Coil Suction Line Filter-Drier Discharge Line Receiver Heater Coil Receiver Liquid Level Sight Glass 1--5 ©...

  • Page 12: Figure 1-3 Ac430 With Bt324 Control Board

    Figure 1-3 AC430 With BT324 Control Board X3, Connector, Controller/Driver Display HTR1, Relay, Evaporator High Speed X11, Connector, Evaporator Blower Motors HTR2, Relay, Evaporator Low Speed X12, Connector, Condenser Fan Motors/ F1, Fuse, Evaporator Motor High Pressure Switch F2, Fuse, Evaporator Motor X13, Connector, Low Pressure Switch, Fresh F3, Fuse, Condenser Motor Air Flap...

  • Page 13: Operation Bt324 Controller

    SECTION 2 OPERATION BT324 CONTROLLER 2.1 STARTING, STOPPING AND OPERATING INSTRUC- Before starting, electrical power must be available TIONS from the bus power supply. A fuse located in the battery compartment passes The BT324 Digital Display is marked with power for the clutch, evaporator and condenser international symbols (See Figure 3-1).

  • Page 14: Sequence Of Operation Bt324

    2.3 SEQUENCE OF OPERATION BT324 The temperature can be adjusted between 64° F (18° C) and 82° F (28° C). 2.3.1 Function of Keys when “Engine On” and controller When the outside temperatures are below 35° F (2° active: C) (adjustable parameter), the cooling function a.
  • Page 15 NOTE e. Press Key 4 (blower control) one time and release. After the display shows the word “Code” The display will show the mode “Fah” for temperatures in °F or the mode “Cel” for you have 5 seconds to enter the correct ac­ temperatures in °C.

  • Page 16: Troubleshooting

    SECTION 3 TROUBLESHOOTING Table 3-1 General System Troubleshooting Procedures INDICATION - REFERENCE POSSIBLE CAUSES TROUBLE SECTION System Will Not Cool Compressor will not run Drive-Belt loose or defective Check Clutch coil defective Check/Replace Clutch malfunction Check/Replace Compressor malfunction See Table 1-2 Electrical malfunction Coach power source defective Check/Repair...

  • Page 17: No Evaporator Air Flow Or Restricted Air Flow

    Table 3-1 General System Troubleshooting Procedures - Continued INDICATION - REFERENCE POSSIBLE CAUSES TROUBLE SECTION Abnormal Noise Or Vibrations - Continued Condenser or evaporator fans Loose mounting hardware Check/Tighten Defective bearings Replace Blade interference Check Blade missing or broken Check/Replace No Evaporator Air Flow Or Restricted Air Flow Air flow through coil blocked Coil frosted over...

  • Page 18: Service

    SECTION 4 SERVICE WARNING Be sure to observe warnings listed in the safety summary in the front of this manual before per­ forming maintenance on the hvac system WARNING Read the entire procedure before beginning work. Park the coach on a level surface, with park­ ing brake applied.

  • Page 19: Installing R-134A Manifold Gauge/Hose Set

    When both valves open (turned the manifold gauge set. Mid-seat both hand valves on counterclockwise), high pressure vapor will flow into the manifold gauge set and allow the pressure in the the low side. When only the low pressure valve is manifold gauge set to be drawn down to low side open, the system can be charged or evacuated.

  • Page 20: Manifold Gauge Set

    5 cfm (8.5 m /hr) volume displace­ To check for leaks in the refrigeration system, ment, (MCC P/N 07-00176-11), and a good mi­ perform the following procedure: cron gauge (MCC P/N 07-00414-00). 4--3 © 2012 Mobile Climate Control T-353 Rev.

  • Page 21: Adding Refrigerant To System

    c. Keep the ambient temperature above 60°F f. When correct charge has been added (refer to (15.6°C) to speed evaporation of moisture. If am­ paragraph 1.3, refrigerant specifications), close cyl­ bient temperature is lower than 60°F (15.6°C), ice inder valve and front seat manifold discharge may form before moisture removal is complete.

  • Page 22: Checking High Pressure Switches

    4.9.2 Checking High Pressure Switches point, the switch contacts should close, indicating no resistance (continuity) on the ohmmeter. g. Replace switch if it does not function as outlined WARNING above. 4.9.3 Checking Low Pressure Switches Do not use a nitrogen cylinder without a a.

  • Page 23: Servicing The Heat Valve

    c. Connect manifold gauge set and reclaimer to the 2. Continuous over-voltage, more than 10% or Un­ filter drier service valve access ports and reclaim der-voltage of more than 15%. any refrigerant contained in the filter drier. 3. Incomplete magnetic circuit due to the omission of the coil housing or plunger.

  • Page 24: Service Valves

    f. Refill and bleed coolant lines. TO LIQUID LINE g. Connect wire leads and test operation. VALVE CAP SERVICE PORT VALVE STEM TO FILTER/DRYER Service Valve Service Valve Frontseated Backseated (clockwise) (counterclockwise) Figure 4-5 Heat Valve Figure 4-6 Service Valve R134a (High Side) 1.

  • Page 25: Thermostatic Expansion Valve

    Diffuser Composite Frame Air Filter Composite Frame Return Air Filter Figure 4-9 Filter, Diffuser and Composite Frame g. Place filter and diffuser into composite frame, with filter element down (See Figure 4-9). Figure 4-7 Return Air Grill Assembly With Air Filter Showing c.

  • Page 26: Valve Replacement

    evaporator regardless of suction pressure. The valve j. Run the coach for approximately 30 minutes on functions are: (a) automatic control of refrigerant fast idle. flow to match the evaporator load and (b) k.Check refrigerant charge. (Refer to 4.7.1) prevention of liquid refrigerant entering the 4.14.2 Superheat Measurement compressor.
  • Page 27 h. From the temperature/pressure chart, determine j. The superheat may cycle from a low to high read­ the saturation temperature corresponding to the ing. Monitor the superheat taking readings every evaporator outlet pressure. 3-5 minutes for a total of 5-6 readings. Calculate the superheats, add the readings and divide by the number of readings taken to determine average su­...

  • Page 28: Table 4-1 R-134A Temperature - Pressure Chart

    Table 4-1 R-134a Temperature - Pressure Chart Temperature Vacuum Temperature Pressure ° ° “/hg cm/hg kg/cm@ ° ° psig kg/cm@ 14.6 49.4 37.08 0.49 24.5 168.9 1.72 1.69 26.1 180.0 1.84 1.80 12.3 41.6 31.25 0.42 27.8 191.7 1.95 1.92 32.8 24.64 0.33...

  • Page 29: Electrical

    SECTION 5 ELECTRICAL 5.1 INTRODUCTION conditioning units which are fitted with two (2) double-shafted evaporator blower/motor This section includes electrical wiring schematics. assemblies and two (2) condenser fan motors. The schematics shown in this section provides Figure 5-2 thru Figure 5-6 shows the BT324 information for the AC430 model rooftop air controller used with the AC430 system.
  • Page 30 98--67037--00 5--2 © 2012 Mobile Climate Control T-353 Rev. 01/2013...
  • Page 31 98--67037--00 5--3 © 2012 Mobile Climate Control T-353 Rev. 01/2013...
  • Page 32 98--67037--00 5--4 © 2012 Mobile Climate Control T-353 Rev. 01/2013...
  • Page 33 98--67037--00 5--5 © 2012 Mobile Climate Control T-353 Rev. 01/2013...
  • Page 34 98--67037--00 5--6 © 2012 Mobile Climate Control T-353 Rev. 01/2013...
  • Page 35 5--7 © 2012 Mobile Climate Control T-353 Rev. 01/2013...
  • Page 36 (- - ) LLSV ACR2 X12--6 X13--1 5 AMP X12--5 X13--2 X3--14 COMP CLUTCH HTR2 HTR1 X3--15 COOLANT PUMP RELAY 10 AMP HTR2 X3--16 COOLANT VALVE RELAY 10 AMP BT- -13 X3--11 X3--10 (NOT USED) BT- -18 BT- -10 HTR1 X3--9 BT- -7 GREY...
  • Page 37 INDEX Maintenance Schedule, 4-1 Air Filters, 4-7 Manifold Gauge Set, 4-2 Apex Unit, 1-2 Noncondensibles, 4-4 Circuit Breaker, 1-4 Compressor, 1-3 Condenser Fan, 1-3 Condensing Section, 1-2 Operating Instructions, 2-1 OPERATION, 2-1 DESCRIPTION, 1-1 Pre-Trip Inspection, 2-1 Pump Down, 4-3 ELECTRICAL, 5-1 Evacuation, 4-3, 4-4 Refrigerant Charge, 1-3, 4-3, 4-4...
  • Page 38 MCC provides exceptional performance in mobile climate comfort. www.mcc-hvac.com Member of MCC Group Certified ISO 9001 and ISO 1 4001. Specifications subject to change without notice. MCC is a registered trademark. 3189 Farmtrail Road York PA 17406 USA Tel: 1--800--673--2431 Fax: 1--717--764--0401 T-353 Rev.

This manual is also suitable for:

68ac430-100-468ac430-100-268ac430-100-568ac430-100-668ac430-100-768ac430-100-8

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