MCC 68AC430-100 Operation & Service Manual Download Page 3

Page: 3 / 38

2012 Mobile Climate Control

T-353 Rev. 01/2013

TABLE OF CONTENTS (Continued)

SERVICE

4-1

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4.1

MAINTENANCE SCHEDULE

4-1

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4.2

REMOVING COVER

4-1

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4.3

MANIFOLD GAUGE SET

4-1

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4.3.1

Installing R-134a Manifold Gauge/Hose Set

4-2

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4.4

REMOVING THE REFRIGERANT CHARGE

4-3

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4.4.1

Removing Entire System Charge

4-3

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4.5

REFRIGERANT LEAK CHECK

4-3

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4.6

EVACUATION AND DEHYDRATION

4-3

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4.6.1

General

4-3

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4.6.2

Preparation

4-3

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4.6.3

Procedure for Evacuation and Dehydrating System

4-4

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4.7

ADDING REFRIGERANT TO SYSTEM

4-4

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4.7.1

Checking Refrigerant Charge

4-4

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4.7.2

Adding Full Charge

4-4

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4.8

CHECKING FOR NONCONDENSIBLES

4-4

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4.9

CHECKING AND REPLACING HIGH OR LOWPRESSURE CUTOUT SWITCH

4-4

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4.9.1

Replacing High Or Low Pressure Switches

4-4

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4.9.2

Checking High Pressure Switches

4-5

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4.9.3

Checking Low Pressure Switches

4-5

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4.10 FILTER-DRIER

4-5

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4.10.1 To Check Filter-Drier

4-5

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4.10.2 To Replace Filter-Drier Assembly

4-5

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4.11 SERVICING THE HEAT VALVE

4-6

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4.11.1 Coil Replacement

4-6

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4.11.2 Internal Part Replacement

4-6

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4.11.3 Replace Entire Valve

4-6

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4.12 SERVICE VALVES

4-7

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4.13 REPLACING RETURN AIR FILTERS

4-7

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4.14 THERMOSTATIC EXPANSION VALVE

4-8

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4.14.1 Valve Replacement

4-9

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4.14.2 Superheat Measurement

4-9

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ELECTRICAL

5-1

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5.1

INTRODUCTION

5-1

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LIST OF TABLES

Table 1-1 68AC430 Models

1-1

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Table 1-2 Additional Support Manuals

1-1

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Table 3-1 General System Troubleshooting Procedures

3-1

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Table 4-1 R-134a Temperature - Pressure Chart

4-11

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Summary of Contents for 68AC430-100

Page 1: ...OPERATION SERVICE for 68AC430 100 REV 01 2013 T 353 Manual T 353 2012 Mobile Climate Control...

Page 2: ...CTIONS 2 1 2 1 1 Starting 2 1 2 1 2 Stopping 2 1 2 2 PRE TRIP INSPECTION 2 1 2 3 SEQUENCE OF OPERATION BT324 2 2 2 3 1 Function of Keys when Engine On and controller active 2 2 2 3 2 Illuminating Indi...

Page 3: ...HECKING AND REPLACING HIGH OR LOWPRESSURE CUTOUT SWITCH 4 4 4 9 1 Replacing High Or Low Pressure Switches 4 4 4 9 2 Checking High Pressure Switches 4 5 4 9 3 Checking Low Pressure Switches 4 5 4 10 FI...

Page 4: ...7 Return Air Grill Assembly With Air Filter Showing 4 8 Figure 4 8 Diffuser and Filter Element 4 8 Figure 4 9 Filter Diffuser and Composite Frame 4 8 Figure 4 10 Return Air Grill Assembly With Diffuse...

Page 5: ...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 startin...

Page 6: ...nect 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 Fi...

Page 7: ...ng 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 auto...

Page 8: ...the thermostatic expansion valve in the evaporator assembly The service valves enable isolation of the filter drier for service 1 2 3 Evaporator Section Theevaporatorsection includesthe evaporatorcoi...

Page 9: ...ens at 360 10 psig 20 41 0 68bar Closes at 280 10 psig 13 61 0 68bar e Low Pressure Switch LPS Normally Open Opens at 6 3psig 0 41 0 20 bar Closes at 25 3 psig 1 7 0 20 bar 1 4 ELECTRICAL SPECIFICATIO...

Page 10: ...s the receiver and passes through the receiver outlet service valve through a filter drier where a desiccant keeps the refrigerant clean and dry From the filter drier the liquidrefrigerant thenflows t...

Page 11: ...3 2 10 11 8 7 7 Figure 1 2 Refrigerant Heat Flow Diagram AC430 1 Thermal Expansion Valve 2 Liquid Line Sight Glass 3 Fusible Plug 4 Dash Air Liquid Line 5 Suction Line 6 Discharge Line 7 Heater Coil...

Page 12: ...DCPower Connection 6 NEG Ground Connection 7 CF1 Condenser Fan Relay 1 8 CF2 Condenser Fan Relay 2 9 LLSV Liquid Line Solenoid Valve Relay 10 AC1 Condenser Fan On Relay 11 AC2 Condenser Fan On Relay 1...

Page 13: ...gure 3 1 on the dis play to trigger the start up sequence c After the pre trip inspection is completed the switches may be set in accordance with the desired control modes 2 1 2 Stopping Toggling the...

Page 14: ...interior temperature The temperature can be adjusted between 64 F 18 C and 82 F 28 C When the outside temperatures are below 35 F 2 C adjustable parameter the cooling function remains disabled 2 4 3...

Page 15: ...Key one time and release d Press Key 3 Recirculating Air Fresh Air one time and release e Press Key 4 blower control one time and release The display will show the mode Fah for temperatures in F or th...

Page 16: ...porator air flow or restriction 3 5 Heating system Heat valve stuck open 3 7 3 3 Abnormal Pressures High discharge pressure Refrigerant overcharge Noncondensable in system Condenser motor failure Cond...

Page 17: ...high super heat Low refrigerant charge Wax oil or dirt plugging valve orifice Ice formation at valve seat Power assembly failure Loss of bulb charge Broken capillary tube 4 7 Check 4 6 Replace Replac...

Page 18: ...nser evaporator coils and air filters for cleanliness Check refrigerant hoses fittings and component connections for leaks Feel filter drier for excessive temperature drop across drier See above None...

Page 19: ...he manifold gauge hose set for reading pressures do the following 1 Connect the field service couplers see Figure 4 1 to the high and low in line service ports 2 Turn the field service coupling knobs...

Page 20: ...vice valves should be back seated b If system is without refrigerant charge system with refrigerant vapor to build up pressure be tween 20 to 30 psig 1 36 to 2 04 bar c Add sufficient nitrogen to rais...

Page 21: ...y connecting charging hose from container to center connec tion on gage manifold Purge air from hoses d Note weight of refrigerant and cylinder e Open cylinder valve backseat discharge valve on gauge...

Page 22: ...s a Disconnect wiring and remove switch from sys tem b Connect an ohmmeter across switch terminals If the switch is good the ohmmeter will indicate an infinite reading on an ohmmeter no continuity c C...

Page 23: ...AC430 rooftop air conditioning system There are onlythree possiblevalve malfunctions coil burnout failure to open or failure to close Coil burnout may be caused by the following 1 Improper voltage 2 C...

Page 24: ...uld always be backseated before removing the service port cap Turning the valve stem clockwise all the way forward will frontseat the valve to isolate the system and open the service port SERVICE PORT...

Page 25: ...te Frame Diffuser Air Filter Figure 4 9 Filter Diffuser and Composite Frame g Place filter anddiffuser intocomposite frame with filter element down See Figure 4 9 Captive 1 4 Fasteners Figure 4 10 Ret...

Page 26: ...ation g Fasten equalizer line to the expansion valve h Leak check the new valve Refer to paragraph 4 5 i Evacuate and recharge the system Refer to para graph 4 6 j Run the coach for approximately 30 m...

Page 27: ...ract the saturation tem perature from this temperature The difference is the superheat of the suction gas j The superheat may cycle from a low to high read ing Monitor the superheat taking readings ev...

Page 28: ...7 18 5 127 6 1 30 1 28 22 6 19 9 137 2 1 40 1 37 24 4 21 4 147 6 1 50 1 48 26 3 22 9 157 9 1 61 1 58 Temperature Pressure F C psig kPa kg cm bar 28 2 24 5 168 9 1 72 1 69 30 1 26 1 180 0 1 84 1 80 32...

Page 29: ...mation for the AC430 model rooftop air conditioning units which are fitted with two 2 double shafted evaporator blower motor assemblies and two 2 condenser fan motors Figure 5 2 thru Figure 5 6 shows...

Page 30: ...5 2 2012 Mobile Climate Control T 353 Rev 01 2013 98 67037 00 Figure 5 2 Evaporator Motors...

Page 31: ...5 3 2012 Mobile Climate Control T 353 Rev 01 2013 98 67037 00 Figure 5 3 Condenser Motors...

Page 32: ...5 4 2012 Mobile Climate Control T 353 Rev 01 2013 98 67037 00 Figure 5 4 BT324 Controls With 1 Compressor...

Page 33: ...5 5 2012 Mobile Climate Control T 353 Rev 01 2013 98 67037 00 Figure 5 5 BT324 Control Circuit...

Page 34: ...5 6 2012 Mobile Climate Control T 353 Rev 01 2013 98 67037 00 Figure 5 6 AC430 With BT324 Control...

Page 35: ...NSOR GRD 86 85 ATS SYMBOL DESCRIPTION INDICATES AMBIENT TEMPERATURE SENSOR ATS INDICATES FUSE WITH MANUAL RESET INDICATES FUSE INDICATES ELECTRICAL COMPONENT INDICATES RELAY COIL INDICATES RELAY CONTA...

Page 36: ...86 85 30 87 30 87 30 87 30 87 10 AMP 10 AMP X3 15 X3 16 HTR1 HTR2 30 87 30 87 5 AMP F7 ACR2 A HPS B X12 5 X12 6 A LPS B X13 1 X13 2 LLSV 86 85 30 87 BT324CONTROLLER X3 14 X3 11 COMP CLUTCH A B COOLANT...

Page 37: ...at Valve 4 6 Heating Cycle 1 4 High Pressure Switch 1 3 L Low Pressure Switch 1 3 1 4 M Maintenance Schedule 4 1 Manifold Gauge Set 4 2 N Noncondensibles 4 4 O Operating Instructions 2 1 OPERATION 2 1...

Page 38: ...ormance in mobile climate comfort Every driver deserves the best possible vehicle climate with MCC products www mcc hvac com Member of MCC Group S Certified ISO 9001 and ISO 1 4001 Specifications subj...

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