Carrier DM-4 Power Pack Operation manual

DM-4
Power Pack
T-270
Bus Air
Conditioning
Unit

Carrier Transicold Division, Carrier Corporation, P.O. Box 4805, Syracuse, N.Y. 13221
SERVICE MANUAL
OPERATION AND
BUS AIR CONDITIONING UNIT
DM-4
POWER PACK
Carrier Corporation 1995 DPrinted in U. S. A. 0695

i
TABLE OF CONTENTS
Section Page
1 DESCRIPTION 1-1.........................................................
1.1 Introduction 1-1............................................................
1.2 Engine Data 1-1............................................................
1.3 Engine Screw Threads 1-1....................................................
1.4 Lubrication System 1-1.......................................................
1.5 Safety Devices 1-3...........................................................
1.6 Engine Air System 1-3.......................................................
1.7 Compressor Data 1-3........................................................
1.8 Compressor Unloader 1-4....................................................
1.9 Switches and Controls 1-4....................................................
1.9.1 Introduction 1-4.....................................................
1.9.2 Main Control and Gauge Panel 1-4.....................................
1.9.3 Driver’s Control Panel 1-5.............................................
1.10 Alternator 1-5..............................................................
1.10.1 Integral Voltage Regulator 1-5.........................................
1.11 Starter Lockout (SLO) 1-5....................................................
2OPERATION 2-1...........................................................
2.1 Pre-Trip Inspection 2-1.......................................................
2.2 Starting and Stopping Instructions 2-1..........................................
3 TROUBLESHOOTING 3-1...................................................
3.1 Diesel Engine 3-1...........................................................
3.1.1 Engine Will Not Start 3-1..............................................
3.1.2 Engine Starts Then Stops 3-1..........................................
3.1.3 Starter Motor Malfunction 3-1.........................................
3.1.4 Malfunction in the Engine Starting Circuit 3-2............................
3.2 Alternator 3-2..............................................................
4SERVICE 4-1...............................................................
4.1 Maintenance Schedule 4-1....................................................
4.2 Priming the Fuel System 4-2..................................................
4.3 Engine Service and Components 4-2...........................................
4.3.1 Cooling System 4-2...................................................
4.3.2 Lube Oil Filter 4-2...................................................
4.3.3 Servicing the Speed Control Solenoid and Linkage 4-2.....................
4.3.4 Adjusting Engine Speed 4-3...........................................
4.3.5 Engine Air Cleaner 4-3...............................................
4.3.6 Engine Crankcase Breather 4-3........................................
4.3.7 Servicing Fuel Pump 4-4...............................................
4.3.8 Servicing Glow Plugs 4-4..............................................
4.4 Servicing and Adjusting V-belts 4-4............................................
4.4.1 Water Pump V-belt 4-4................................................
4.4.2 Alternator V-belts 4-4.................................................
4.5 Replacing the Compressor 4-5.................................................
4.6 Checking Compressor Oil Level 4-6............................................

ii
TABLE OF CONTENTS (CONTINUED)
Section Page
5ELECTRICAL
5.1 Introduction 5-1............................................................
LIST OF ILLUSTRATIONS
Figure Page
1-1 Power Pack DM-4 --- Front View 1-2..........................................
1-2 Power Pack DM-4 --- Control Panel 1-2........................................
1-3 Lube Oil Flow Diagram 1-3.................................................
1-4 Fuel System Diagram 1-3...................................................
1-5 Compressor Cylinder Head Unloaded 1-4.....................................
1-6 Compressor Cylinder Head Loaded 1-4.......................................
1-7 Alternator Schematic Diagram 1-5...........................................
4-1 Speed Control Solenoid 4-2.................................................
4-2 Engine Speed Adjustment 4-3...............................................
4-3 Engine Crankcase Breather 4-3..............................................
4-4 Mechanical Fuel Pump 4-4..................................................
4-5 Removing V-Belt from Engine Adapter Drive Sheave 4-5........................
4-6 Compressor Drive Assembly 4-5.............................................
4-7 Compressor 4-6...........................................................
5-1 Electrical Wiring Schematic Diagram --- DM-4 Power Pack 5-2....................
LIST OF TABLES
Table Page
1-1 Safety Devices 1-3.........................................................
4-1 V-Belt Tension 4-5.........................................................

1-1
SECTION 1
DESCRIPTION
1.1 INTRODUCTION
ThismanualcontainsOperatingData,ElectricalData
and Service instructions for the DM-4 Power Pack.
WARNING
Beware of V-belts and drive components as the
unit may be started remotely. Make sure the
control switch is in the OFF position.
The unit is a one piece, self contained, pre-wired
diesel powered compressor/alternator drive unit. When
connected to a specific evaporator - condenser section it
will form a complete self powered bus air-conditioning
system.
The unit consists of an engine compressor assembly,
belt driven heavy duty alternator, radiator and fan
assembly, electrical control panel and associated
components.
The compressor is equipped with unloaders as
standardequipment.Unloaders areused asacompressor
capacity control to unload the compressor during periods
of reduced loads. This provides closer temperature
control, and reduces power required to operate the
compressor, thus reducing fuel consumption.
The engine gives excellent fuel economy and has easy
starting characteristics. The engine is equipped with
spin-on lube oil and fuel filters for easier filter changes.
NOTE
Throughout this manual, whenever the “left” or
“right” handside ofthe engineis referred to, itis
the side as viewed from the flywheel end of the
engine.
The diesel engine drives the compressor directly
through a nylon drive gear and adapter. The adapter also
includes a V-belt sheave which drives the system
alternator.
Electricalpowerforthecontrolsystemandforstarting
the engine is provided by the bus 12-volt batteries. The
unitmaybestartedfromthemaincontrolpanellocatedon
the Power Pack frame or from the driver’s control panel.
Asa safetyprecautionthedriver’s startswitchisrendered
inoperativewhenever theunit switchon the mainpanel is
in the OFF position.
1.2 ENGINE DATA
Engine Model: CT-134TV
Displacement: 2.2liters (134 in3)
No. of cylinders: 4
Horsepower: 34 @ 1900rpm
25 @ 1350rpm
Coolant capacity: 7.6 liters (2-1/2 gal.)
Oil capacity w/filter: 14 liters (15 qts.)
Operating speeds: High-1900 rpm
Low-1350 rpm
Injector setting: 140-150 km/cm2)
Fuel type: Diesel #1 or #2
Firing order: 1-3-4-2
Glow plug amperage: 7.0 amps/plug
Valve clearance cold: 0.0071 to 0.0087
1.3 ENGINE SCREW THREADS
All threads used on the diesel engine are metric.
1.4 LUBRICATION SYSTEM
Oil pressure: 40-60 psig (Engine in high speed)
Oil pressure safety switch: Opens @10(3)psig
Lube Oil Viscosity: 30W or 15W40
Oil change interval: First 400 Hours, thereafter as
listed below. CAUTION
The maximum oil change interval is 1 year (for
either approved oil) The only approved synthetic
oil is Mobil Delvac 1. The normal oil change
intervals (listed below) should be reduced if the
engine is operated under extreme conditions
such as in dirty environments.
OilType: APIClassCD MobilDelvac1
Change Interval: 1500 hrs. 3000 hrs.

1-2
1. Radiator Cap
2. Compressor --- 05K
3. Alternator
4. Glow Plug Control
5. Power Relay (PR)
6. Mechanical Fuel Pump
7. Oil Pressure Switch (OP)
8. Air Cleaner
9. Lube Oil Fill
10. Diesel Engine --- CT4-134-TV
11. Fuel Filter
12. Radiator Overflow Reservoir
Figure 1-1. Power Pack DM-4 --- Front View
1. Water Temperature Switch Gauge (WT)
2. High Temperature Coolant Lockout (HTL)
3. Preheat Light (PHL)
4. A/C Stop Light (ASL)
5. Rear Start Switch (RSS)
6. Circuit Breaker 35A (CB1)
7. Circuit Breaker 35A (CB2)
8. Rear Control Switch (RCS)
9. Oil Pressure Gauge
10. Hour Meter (HM)
12345 6
789101112
Figure 1-2. Power Pack DM-4 --- Control Panel
12 345
6
7
8910

1-3
1
2
3
4
5
1. Engine Block
2. Oil Pan
3. Full Flow Oil Filter
4. Engine Oil Connection
5. Oil Pressure Switch
Figure 1-3. Lube Oil Flow Diagram
1.5 SAFETY DEVICES
System components are protected from damage
caused by unsafe operating conditions by automatically
shutting down the engine when such conditions occur.
This is accomplished by the safety devices listed in
Table 1-1.
1.6 ENGINE AIR SYSTEM
The air cleaner is put on the engine to prolong its life
and performance by preventing dirt and grit from getting
into the engine causing excessive wear on all operating
parts. However, it is the responsibility of the operator to
give the air cleaner regular and consistent attention in
accordance with the instructions. If the air cleaner is
allowed to become dirty, the operation of the engine
would be impaired.
1
2
35
6
7
8
10
9
4
Figure 1-4. Fuel System Diagram
1. Fuel Tank
2. Fuel Supply Line
3. Fuel Pump
4. Mechanical Lift Pump
5. Fuel Filter
6. Fuel Bleed Valve
7. Injection Pump
8. Injector Nozzles
9. Fuel Leak-off Line
10. Fuel Return Line
1.7 COMPRESSOR DATA
Compressor Model: Carrier 05K
No. of cylinders: 4
No. of unloaders: 1
Oil charge: 2.6 liters (5.5 pints)
Oil type: Sunisco 3GS (R22)
Castrol Icematic SW-68 (R134a)
Table 1-1. Safety Devices
Unsafe Conditions Safety Devices Device Setting
Low engine oil pressure Oil pressure safety switch Opens below 10 3psig
High engine coolant temperature Coolant temperature sensor
(switch gauge) Opens shutdown circuit above 220 5_F
Excessivecurrentdrawbyglowplug
circuit Manual reset circuit breaker (CB1) Opens @ 35 amps.
Excessive current in control circuit Manual reset circuit breaker (CB2) Opens @ 35 amps.
Excessive compressor discharge
pressure High pressure cutout switch Opens @ 425 10 psig
Closes @ 300 10 psig
Low compressor suction pressure Low pressure cutout switch Opens @ 10 3psig
Closes @ 27 3psig

1-4
1.8 COMPRESSOR UNLOADER
a. Unloaded Operation (Refer to Figure 1-5)
Pressure from the discharge manifold (15) passes
throughthestrainer(9)andbleedorifice(8)tothebackof
thepistonbypassvalve(7).Unlessbledaway,thispressure
wouldtendtoclosethepiston(6)againstthepistonspring
(5) pressure.
Withthesolenoidvalve(1)energizedthesolenoidvalve
stem (2) will open the gas bypass port (3).
Refrigerant pressure will be bled to the suction manifold
(10) through the opened gas bypass port. A reduction in
pressureon the pistonbypassvalvewill takeplacebecausethe
rate of bleed through the gas bypass port is greater than the
rate of bleed through the bleed orifice (8).
Whenthepressurebehindthepistonhasbeenreduced
sufficiently, the valve spring will force the piston bypass
valve back, opening the gas bypass from the discharge
manifold to the suction manifold.
Dischargepressureinthedischargemanifoldwillclose
the discharge piston check valve assembly (14) isolating
the compressor discharge manifold from the individual
cylinder bank manifold.
The unloaded cylinder bank will continue to operate
fully unloaded until the solenoid valve control device is
de-energized andthegasbypassportisclosed.
10
11
12
13
4
6
5
15
14
1
9
23
8
7
1. Solenoid Valve
2. Valve Stem
3. Gas Bypass Port
4. Spring Guide
5. Spring
6. Piston
7. Piston Bypass Valve
8. Bleed Orifice
9. Strainer
10. Suction Manifold
11. Cylinder Discharge
Valve
12. Valve Plate
13. Cylinder Suction
Valve
14. Discharge Piston
Check Valve
Assembly
15. Discharge Manifold
Figure 1-5. Compressor Cylinder Head Unloaded
b. Loaded Operation (Refer to Figure 1-6)
Discharge pressure bleeds from the discharge
manifold (15) through the strainer (9) and bleed orifice
(8)tothesolenoidvalvestem chamber(2) andthebackof
the piston bypass valve (7).
With the solenoid valve (1) de-energized the solenoid
valve stem will close the bypass port (3).
Refrigerant pressure will overcome the bypass valve
spring (5) tension and force the piston (6) forward closing
the gas bypass from the discharge manifold to the suction
manifold.
Theloadedcylinderbankwillcontinuetooperatefully
loadeduntilthesolenoidvalvecontroldeviceisenergized
andthegasbypassportisopened.
7
10 12
15
14
8
9
4
6
5
23 11
13
1
1. Solenoid Valve
2. Valve Stem
3. Gas Bypass Port
4. Spring Guide
5. Spring
6. Piston
7. Piston Bypass Valve
8. Bleed Orifice
9. Strainer
10. Suction Manifold
11. Cylinder Discharge
Valve
12. Valve Plate
13. Cylinder Suction
Valve
14. Discharge Piston
Check Valve
Assembly
15. Discharge Manifold
Figure 1-6. Compressor Cylinder Head Loaded
1.9 SWITCHES AND CONTROLS
1.9.1Introduction
Components required for monitoring and controlling
the diesel engine are located on the main control and
gauge panel (located in the Power Pack) and the driver’s
control panel.
1.9.2Main Control and Gauge Panel
a. Switches
1. Rear Control Switch (RCS)
When placed in the FRONT position the unit is
controlled from the driver’s switch panel. When placed in
the REAR position the unit is controlled from the main
panel only.WhenplacedintheOFFpositiontheunit
cannot be controlled from either panel.

1-5
2. Rear Starter Switch (RSS)
This switch is active only when the (RCS) switch is in
the REAR position. Depressing this switch energizes the
starter circuit.
b. Gauges and Indicators
1. Oil Pressure Gauge (OP)
Theoilpressuregaugeisusedtomonitortheengineoil
pressure. Normal oil pressure is 40-60 psig with engine
running at high speed and at operating temperature.
2. Water Temperature Switch Gauge (WT)
Thisgaugeservesadual function.It isused tomonitor
enginecoolanttemperatureaswellasservingastheswitch
for the high temperature cut out. Normal engine
operating temperature is 180 to 210_F. The switch
function should be set to close at 220-230_F.
3. Hour Meter (HM)
The unit Hour Meter will total unit operating hours
and is useful for scheduling maintenance intervals.
4. Preheat Light (PHL)
The preheat light will illuminate to indicate that the
glow plug circuit has been energized. This function is
controlled automatically by the Preheat controller. The
light will go out when the glow plugs have beenenergized
long enough to reach their required temperature for
starting the engine.
5. A/C Stop Light (ASL)
The AC stop light is activated by the oil pressure cut
out switch. Its purpose is to indicate to the operator that
the unit has stopped.
1.9.3Driver’s Control Panel
a. Switches
1. Front A/C Switch (FAS)
This switch allows the unit to be turned on or off from
the driver’s panel. It is active only when the (RCS) switch
on the unit panel is in the ‘‘front’’ position.
2. Front Starter Switch (FSS)
This switch is active only when the (RCS) switch is in
theFRONTposition.Depressingthisswitchwillenergize
the engine starter circuit.
3. Preheat Light (PHL)
(Same as on main panel )
4. A/C Stop Light (ASL)
(Same as on Main Panel)
1.10 ALTERNATOR
The Power Pack is equipped with a 28 volt-140 amp.
alternator.Thealternatorisconnectedinparallelwiththe
air conditioning alternator driven by the main engine.
Bothofthesealternatorsareusedtoindependentlypower
the air conditioning system.
NOTE:
The Power Pack engine controls and starter are
12 volt and receive power from the bus 12 volt
batteries.
CAUTION
Observe proper polarity when installing battery.
Negative battery terminal MUST be grounded.
Reverse polarity will destroy the rectifier diodes
in the alternator. As a precautionary measure,
disconnect positive battery terminal when
charging batteries. Connecting charger in
reverse will destroy the rectifier diodes in the
alternator.
The alternator converts mechanical and magnetic
energy to alternating current (A.C.) and voltage, by the
rotation of an electromagnetic field (rotor) inside a
three-phase stator assembly. The alternating current and
voltage are changed to direct current and voltage, by
passing the A.C. energy through a three-phase, full wave
rectifier system. Six silicon rectifier diodes are used.
1.10.1 Integral Voltage Regulator
Theregulatorisanelectronictransistorizeddevice.No
mechanical contacts or relays are used to perform the
voltageregulationofthealternatorsystem.Theelectronic
circuitryshouldneverneedadjustmentandthesolidstate
active elements used have proved reliable enough to
warrant a sealed unit. The system is temperature
compensated to permit a constant voltage rate at all
conditions.
The regulator is an electronic switching device. It
senses the system voltage level and switches the voltage
applied to the field in order to maintain proper system
voltage.
1.11 Starter Lockout (SLO)
The starter lockout (SLO) is an electronically
controlled relay that opens the starter motor circuit when
apresetenginespeedisreached.Thesignalsourceforthe
control is the A.C. output of the unit alternator.
Frequency directly proportional to engine speed is
monitored electronically within the control. When the
speedorfrequencyreachesthe desiredsetting orsetpoint
the output relay within the control circuit is switched.
Figure 1-7. Alternator Schematic Diagram

2-1
SECTION 2
OPERATION
2.1 PRE-TRIP INSPECTION
a. Before Starting engine
1. Drain water and sediment from fuel tank sump.
2. Check radiator coolant level. (Add pre-mixed
50/50 permanent anti-freeze and water as required.)
USE ETHYLENE GLYCOL ONLY.
3. Check engine lubrication and fuel filter lines and
connections for leaks. (Tighten connections and/or
replace gaskets.)
4. Check engine oil level (refer to section 1.2).
5. Check V-belts for proper tension, fraying or
cracking. Adjustor replaceas necessary(refertosection
4.4).
6. Check battery connections for cleanliness and
tightness. Clean and coat with protectant.
7. Check engine air cleaner and condition of air
cleaner hose.
b. After Starting Unit
1. Check water temperature. (Should be 180-220_F
after running for 20 minutes)
2. Check oil pressure (refer to section 1.4).
3. Listen for abnormal noises.
4. Check compressor oil level (refer to section 4.6).
5. Observe any signs of fuel or oil leaks.
6. Check radiator hoses and connections for leaks.
2.2 STARTING AND STOPPING INSTRUCTIONS.
a. Starting Instructions, Main Control Panel
1. Place the Rear Control Switch (RCS) in the
REAR position. Observe that the pre heat light is
illuminated indicating that the glow plug controller is
functioning. The light will go out when the glow plugs
have reached the proper temperature for starting. (The
timerequiredtoheattheglow plugswill varydepending
on the temperature of the engine).
2. When the preheat light has gone out, depress the
start switch to crank the engine.
CAUTION:
If the engine should fail to start after 20-30
seconds of cranking. Place the Rear Control
Switch (RCS) in the OFF position and wait
several minutes for the starter motor to cool
down before attempting to restart the unit.
b. To Stop The Unit From The Main Control Panel
Place the Rear Control Switch (RCS) in the OFF
position to stop the unit
c. ToStartTheUnitFromTheDriver’sPanel
NOTE:
The Rear Control Switch (RCS) located on the
unit main control panel must be in the FRONT
position for the driver’s panel to be active.
1. Place the A/C Switch (ACS) in the ON position.
Observe that the preheat light is illuminated indicating
that that glow plug controller is functioning. The light
will go out when the glow plugs have reached the proper
temperature for starting. (The time required toheat the
glowplugswillvarydependingonthetemperatureofthe
engine.)
2. When the preheat light has gone out, depress the
start switch to crank the engine.
CAUTION
If the engine should fail to start after 20-30
secondsof cranking.Placethe A/C switchinthe
OFF position and wait several minutes for the
startermotortocooldown beforeattemptingto
restart the engine.
d. To Stop The Unit From the Driver’s Panel
Place the A/C switch (ACS) in the OFF position to stop
the unit. NOTE:
If the power pack should malfunction and be
shut down by one of the safety cutouts the A/C
stop light will illuminate. Do not attempt to
operate the unit until the cause for the
shutdown has been identified and corrected.

3-1
SECTION 3
TROUBLE SHOOTING
INDICATION/TROUBLE POSSIBLE CAUSES REFERENCE
SECTION
3.1 DIESEL ENGINE
3.1.1 Engine Will Not Start
Starter motor will not crank or
low cranking speed Battery insufficiently charged
Battery posts dirty or defective
Bad electrical connections at starter
Starter motor malfunctions
Starter solenoid defective
Open starting circuit
Incorrect grade of lubricating oil
Check
Check
Check
3.1.3
Engine Manual
3.1.4
1.4
Starter motor cranks but engine
fails to start No fuel in tank Air in fuel system
Water in fuel system
Plugged fuel filter
Plugged fuel lines to injectors
Fuel control operation erratic
Glow plugs defective
Fuel solenoid defective
Fuel pump malfunction
Check
4.2
Drain sump
Replace
Check
Engine Manual
4.3.8
Engine Manual
4.2 or 4.3.7
Starter cranks, engages, but dies
after a few seconds Engine lube oil too heavy Voltage drop in starter cable(s) 1.4 Check
3.1.2 Engine Starts Then Stops
Engine stops after several
rotations Fuel supply restricted No fuel in tank
Leak in fuel system
Faulty fuel control system
Fuel filter restricted
Injector nozzle(s) defective
Injection pump defective
Air cleaner or hose restricted
Safety device open
Open circuit to run solenoid
Fuel pump malfunction
Check
Check
Check
Engine Manual
Replace
Engine Manual
Engine Manual
4.3.5
1.5
Check
4.2 or 4.3.7
3.1.3 Starter Motor Malfunction
Starter motor will not crank or
turns slowly Battery insufficiently charged Battery cable connections loose or oxidized
Battery cables defective
Starter brushes shorted out
Starter brushes hang up or do not make contact
Starter solenoid defective
Switch defective
Engine lube to heavy
Check
Check
Replace
Engine Manual
Engine Manual
Engine Manual
Replace
1.4

3-2
INDICATION/TROUBLE POSSIBLE CAUSES REFERENCE
SECTION
3.1.3 Starter Motor Malfunction (CONTINUED)
Starter motor turns but pinion
does not engage Pinion or ring gear obstructed or worn Clean both, remove burrs,
or replace;
apply grease
Starter motor does not
disengage after switch was
depressed
Start switch defective
Starter solenoid defective Replace Engine Manual
Pinion does not disengage after
engine is running Defective starter Engine Manual
3.1.4 Malfunction in the Engine Starting Circuit
No power to starter motor
solenoid Battery Defective Loose electrical connections Check Tighten
Fuel solenoid does not
energize or does not remain
energized
Battery Defective
Loose electrical connections
Oil pressure safety switch defective
Run relay defective
Water temperature cut out defective
Fuel solenoid defective
FRONT-OFF-REAR switch defective
Check
Tighten
Replace
Replace
Replace
Engine Manual
Replace
3.2 ALTERNATOR
Alternator fails to charge Battery condition
Alternator belt loose or broken
Loose, dirty, corroded terminals, or broken leads
Excessively worn, open or defective brushes
Open blocking diode
Regulator faulty
Open isolation diode
Open field coil
Check
4.4
Check/Repair
Check
Check
Check
Check
Replace
Low or unsteady charging rate Alternator belt loose
Loose, dirty, corroded terminals, or broken leads
Excessively worn, sticky or intermittent brushes
Faulty regulator
Grounded or shorted turns in rotor
Open, grounded or turns in stator
4.4
Check/Repair
Check
Check
Check
Replace
Excessive charging rate (as evi-
denced by batteries requiring to
frequent refilling) or fans noisy
due to excessive speed
Regulator leads loose, dirty, corroded terminals, or wires
broken
Defective regulator
Clean/Repair
Check
Noisy alternator Defective or badly worn V-belt
Worn bearings
Misaligned belt or pulley
Loose pulley
4.4
Replace
4.4
Tighten

4-1
SECTION 4
SERVICE
WARNING
Beware of V-belts and belt driven components as the unit can be started remotely. Before servicing unit, make
sure that the Front-Off-Rear switch is in the “OFF” position Also disconnect the negative battery cable.
NOTE
To avoid damage to the earth’s ozone layer, use a refrigerant recovery system whenever removing refrigerant.
When working with refrigerant you must comply with all government environmental laws, EPA section 608
4.1 MAINTENANCE SCHEDULE
UNIT
O
P
E
R
A
T
I
O
N
REFERENCE
ON OFF OPE
R
A
TION
R
E
F
E
R
E
N
C
E
SECTION
a. Daily Maintenance
X1. Pre-trip inspection --- before starting 2.1.a
X2. Pre-trip inspection --- after starting 2.1.b
X3. Check engine hours Run 10 min.
b. First 400 Hour Maintenance
X1. Pre-trip inspection --- before starting 2.1.a
X2. Change lube oil and filter 4.3.2
X3. Pre-trip inspection --- after starting 2.1.b
X4. Check engine hours Run 10 min.
c. Every 1500 Hour Maintenance (Normal Operating Conditions)
X X 1. Complete 400 Hour Maintenance (Refer to section 1.4 for oil change interval) 4.1.b
X2. Tighten Engine, compressor and unit mounting bolts None
X3. Tighten all electrical connections Tighten
X4. Replace air cleaner element, check hoses and connections 4.3.4
X5. Check water pump bearing for end play None
X6. Check alternator brushes None
X7. Replace fuel filter 4.3.6
d. Every 3000 Hour Maintenance
X X 1. Complete 1500 Hour maintenance 4.1.c
X2. Clean crankcase breather 4.3.5
X3. Replace all V-belts 4.4
X4. Check starter condition Engine manual
X5. Check and adjust injector nozzles Engine manual
e. Every 6000 Hours or 2 Years Maintenance
X1. Check and adjust injector nozzles Engine manual
X2. Check engine compression Engine manual
X3. Adjust engine valves Engine manual
X X 4. Drain and flush cooling system 4.3.1

4-2
4.2 PRIMING THE FUEL SYSTEM
The engine is equipped with a mechanical fuel lift
pump, it is mounted on the engine next to the injection
pump. This pumphas a manual plunger for bleeding fuel
when the fuel tank has been run dry.
Sincetheunitemploysaclosedfuelcircuit,thefollow-
ing steps are recommended:
1. Turnbleedvalve(Red)counter---clockwiseuntilful-
ly opened.
2. Turn the top of the manual plunger counter-clock-
wisetounlockit.Thenrapidlyhandpumpthehandplung-
er untilpositive pressure(resistance)is felt, whichwill in-
dicate fuel flow.
3. Depress and turn the top of the manual plunger
clockwise to lock it in place.
4. Start engine.
5. When engine is running properly, turn bleed valve
clockwise until fully closed.
4.3 ENGINE SERVICE AND COMPONENTS
4.3.1Cooling System
Air flows through the radiator by using the electric
fans. The radiator, externallyandinternallymust beclean
for adequate cooling. The water pump V-belt must be ad-
justedperiodicallytoprovidemaximumefficiency.(Refer
to section 4.4.1)
Dothefollowingservicetothecoolingsystem
CAUTION
Useonlyethyleneglycolcoolant(withinhibitors)
in system as glycol by itself will damage the
system. Always add pre-mixed 50/50 coolant and
water to radiator/engine. Never exceed more
than 50% concentration of coolant. Use a low
silicate coolant meeting GM specification GM
6038M or equal.
1. Removeall foreignmatterfromtheradiator coil by
reversing the normal air flow. Compressed air or water
maybeusedasacleaningagent.Itmaybenecessarytouse
warm water mixed with any good commercial detergent.
Rinse with fresh water if a detergent is used.
2. Draincoolant completely byremovinglowerradia-
tor hose and radiator cap.
3. Installhoseandfillsystemwithclean,untreatedwa-
tertowhich threetofivepercentofanalkalinebaseradia-
tor cleaner should be added (6 oz. dry to one gallon)
4. Run engine 6 to 12 hours and drain system while
warm. Rinse system three times after it has cooled down.
Refill system with water.
5. Runenginetooperatingtemperature.Drainsystem
again and fill with treated water/coolant. (see Caution
Note and refer to section 1.2) NEVER POUR COLD
WATER INTOAHOTENGINE,howeverhotwater can
always be added to a cold engine.
4.3.2Lube Oil Filter
After warming up the engine, stop engine, remove
drain plug from the reservoir and drain engine lube oil.
Lightly oil gasket on filter before installing.
CAUTION
When changing oil filter, the new filter should be
primed with clean oil, if the filter is not primed,
the engine may operate for a period with no oil
supplied to the bearings.
Replace filter and add lube oil. (Refer to section 1.4)
Warm up engine and check for leaks.
4.3.3 Servicing the Speed Control Solenoid and Linkage
1
23
5
4
1. Solenoid
2. Bolt
3. Solenoid Bracket
4. Linkage (Speed)
5. Clip
Figure 4-1. Speed Control Solenoid
1. Disconnect wiring to solenoid. Disconnect linkage
arm (item 4) from solenoid. Remove mounting hardware
from solenoid and then remove solenoid.
2. Install replacement solenoid and mounting hard-
ware. Do not tighten at this time.
3. Attachlinkage to solenoidandinstall theclip tothe
solenoid arm.
4. Holdthespeedleveragainstthehighspeedstopand
check the rpm (refer to section1-2) Adjust the low speed
stop screw stop if necessary.
5. Checkenginespeed.Withtheenginestopped,place
a mark on the crankshaft sheave (white paint for exam-
ple). Speed may be verified by a Strobette model 964
(strobe tachometer) Carrier Transicold P/N 07-00206.
6. Holdthespeedleveragainstthehighspeedstopand
checktherpm(refertosection1-2).Adjustthehighspeed
stop screw if necessary.
7. Energize the speed solenoid. Push the solenoid so
thatthe speedarmrests against thehighspeedstopscrew
andtightenthesolenoidmountingbolts.Connectwiresto
solenoid.

4-3
4.3.4 Adjusting Engine Speed
Refer to section 1.2 for correct engine speed.
To Check Engine Speed:
Withtheenginestopped,placeamark(whitepaintfor
example)onthecrankshaftsheave.Startengineandverify
engine speed by using a Strobette-model 964 (Strobe-
tachometer), Carrier Transicold Part No. 07-00206.
To Increase Speed:
Loosen jam nut “B.” Turn capscrew “B” clockwise
until correct speed is achieved, then tighten jam nut “B”
and check engine speed (see Figure 4-2).
To Decrease Speed:
Loosen jam nut “B.” Turn capscrew “B” counter-
clockwiseuntilcorrectspeedis achieved,thentightenjam
nut “B” and check engine speed (see Figure 4-2).
1
2
3
1. Speed Lever
2. Jam Nut “B”
3. Capscrew “B”
Figure 4-2. Engine Speed Adjustment
4.3.5Engine Air Cleaner
a. Inspection
The dry type aircleaner should be inspected regularly
for leaks. A damaged air cleaner or hose canseriously af-
fecttheperformance andlifeofthe engine.Theair clean-
erisdesignedtoeffectivelyremovecontaminantsfromthe
airstreamenteringtheengine.Anexcessiveaccumulation
ofthesecontaminantsintheaircleaner willimpair itsop-
eration, therefore, a service must be set up and followed.
Remember that the air cleaner cleans the air, but the air
cleaner requires cleaning. The following simple service
steps are easily made while the engine is being serviced.
1. Check all connections for mechanical tightness. Be
sure air cleaner outlet pipe is not fractured.
2. Incaseofleakageandifadjustmentdoesnotcorrect
theproblem,replacenecessarypartsorgaskets.Swelledor
distorted gaskets must always be replaced.
4.3.6Engine crankcase breather
Theengineusesaclosedtypebreatherwiththebreath-
er line attached to the cylinder head cover. The breather
assembly should be cleaned once a year or at every 3000
hour maintenance interval (which ever comes first).
2
3
4
5
6
1
8
7
Figure 4-3. Engine Crankcase Breather
1. Cylinder Head Cover
2. Breather Cover
3. Breather Element
4. Plate
5. Breather Oil Shield
6. Bolt
7. Breather Assembly
8. O-Ring

4-4
4.3.7Servicing Fuel Pump
Due to foreign particles in the fuel, the fuel filter may
become pluggedor restricted, andthe engine will loseca-
pacity. The filter must be cleaned on a regular schedule
such as unit pre-trip or when the oil and fuel filters are
changed.
1. Turn the nut counter-clockwise to loosen and re-
move (item 1, Figure 4-3)
2. Remove banjo fitting (item 2) and let it hang loose,
makingsuretokeepcopperrings(item4)forreplacement.
3. Turn filter (item 3) counter-clockwise and remove.
Check and clean.
4. To install reverse steps 1 through 3.
1
2
3
1
4
1. Nut
2. Banjo
3. Filter
4. Copper Rings
Figure 4-4. Mechanical Fuel Pump
4.3.8Servicing Glow Plugs
When energized, the glow plugs draw a nominal 7.0
amps at 10.5 volts. When servicing, the glow plug is fitted
carefully in the cylinder head to prevent damage to glow
plug.Torquevaluefortheglowplug is14to18ft-lbs(1.9to
2.5 mkg).
a. Checking for defective glow plug
1. One method is to place an ammeter (clip on type
ammeter) in series with each glow plug and energize the
glow plugs.Eachplug (if good)shouldshow7to10 amps
draw.
2. A second method is to disconnect the wire connec-
tion to each plug and test the resistance from the plug to
groundontheengineblock.Threadingshouldbe0.7to1.2
ohms if the plug is good.
4.4 SERVICING AND ADJUSTING V-BELTS
WARNING
Beware of V-belts and belt driven components
as the unit can be started remotely
4.4.1Water Pump V-Belt
ThewaterpumpV-beltisdrivenbyasheave ontheen-
gine crankshaft.Frayed,crackedorwornbeltsmust bere-
placed. Adjustment is achieved by altering the position of
the front side idler.
When replacing the V-belt avoid excessive force when
applying tension to the V-belt to prevent damage to the
water pump bearings. Refer to NO TAG for correct belt
tension.
4.4.2 Alternator V-Belts
a. To Replace V-Belts
1. DisconnectnegativebatterycableandloosenV-belt
tension
2. Match mark adapter to engine flywheel (see figure
4-4-A) for ease of assembly.
3. Remove six bolts (5/16-18 x 1) securing adapter
drivesheavetoengineflywheel,Figure4-4-A.
4. Insert 2 of the six bolts (5/16-18 x 1) into the
threaded holes (jacking holes) provided on engine adapt-
er.Jackadapterfromengineflywheel.Removethe2bolts
from adapter. Insert a pry bar between engine flywheel
andadapter,Figure4-4-Aandslidetheadapter-sheaveto-
ward the compressor enough to change the V-belts as
showninFigure4-4-B.ReplaceV-belts.
5. Pry the adapter back toward the flywheel or use
5/16-18 x 2-1/2 bolts (3) in everyother holeof theadapter
and take up evenly on the bolts until the 5/16-18 x 1 bolts
willstartintheengineflywheel.Applythreadsealer(Loc-
tite#262)totheboltsusedtosecuretheadaptertothefly-
wheel.Takeuponallboltsevenlyandthentorquetoaval-
ue of 28 ft-lb (3.87mkg).
6. Place V-belts on the alternator sheave and adjust
tension. Refer to Table 4-1 for correct belt tension. Using
excessive tension may damage alternator bearings.
7. Reconnect battery ground cable and start unit. Al-
low to run for 10 minutes to allow belts to seat.

4-5
8. Turn off and check belt tension.
Figure A
Figure B
Figure 4-5. Removing V-Belt from Engine Adapter
Drive Sheave
Table 4-1. V-Belt Tension
Belt Tension
Water Pump 35 --- 40 foot pounds
Alternator 70 --- 80 foot pounds
4.5 REPLACING THE COMPRESSOR
If compressor is inoperative and unit still has refriger-
ant pressure, frontseat suction and discharge service
valves to trap most of the refrigerant in the unit.
If compressor runs, pump down the unit.
1. Removethetworearcompressormountingbracket
bolts (compressor shock mounts).
2. Block up engine.
3. Slowlyreleasecompressor pressureinto arecovery
system.
4. Remove bolts from suction and discharge service
flanges.
5. Remove oil filter and bracket.
6. Disconnect battery ground cable. Unbolt power
relay and move out of the way.
7. Disconnect wiring to unloader valve assembly and
high and low pressure cutouts.
8. Remove ten bolts from engine compressor spacer.
9. Disconnect ground strap from frame.
10. Attach sling or other device to compressor.
11. Slidecompressor enoughtoclear nylon drivegear,
Figure 4-4 and remove compressor from unit.
12. Drain oil from defective compressor before shipping.
13. Theoriginal unloader valvemust be transferredto
the replacement compressor. The plug arrangement re-
moved from the replacement is installed in the original
compressoras aseal.Ifpistonisstuck,itmaybeextracted
by threading a socket head cap screw into topof piston. A
smallTeflonseatringatbottomofpistonmustbere-
moved. NOTES
The service replacement compressor is sold
without shutoff valves (but with valve pads).
Customer should retain the original unloader
valve for use on the replacement compressor.
Check oil level in service replacement
compressor. (Refer to section 1.7)
8
5
34
1
26
7
9
10
1. Compressor
2. Bolts
3. Spacer
4. Key
5. Compressor Drive Gear
6. Locking Tab
7. Nylon Drive Gear
8. DriveSheaveBolts
9. Engine adapter-Drive Sheave
10. Alternator Belt
Figure 4-6. Compressor Drive Assembly
14. Remove the high and low pressure switches and
install on new compressor after checking switch settings.
Install compressor frame to new compressor (if removed
with defective compressor).

4-6
15. Install compressor in unit by reversing steps 1
through 14. It is recommended using new locknuts when
replacing compressor. Torque bolts to a value of 46 ft/lb
(6.4mkg).Installnewgasketsonservicevalvesandtighten
bolts uniformly.
16. Attachservice gaugemanifold lines to thesuction
anddischargeservicevalves.Connectmanifoldtovacuum
pump. Evacuate compressor to 500 microns (29.90” Hg
vacuum 75.9 cm Hg vacuum) . When completed, close
gauge valves and disconnect vacuum pump.
17. Fully open (backseat) both suction and discharge
service valves and partially open to activate gauges.
18. Start unit and check refrigerant level. Also check
for noncondensibles.
19. Check compressor oil level. Add oil as necessary.
20. Check compressor unloader operation and check
refrigerant cycle.
4.6 CHECKING COMPRESSOR OIL LEVEL
a. To Check the Oil Level in the Compressor
1. Operate the unit in fully loaded high speed cool for
at least 20 minutes.
2. Checktheoilsightglassonthecompressortoensure
thatnofoamingoftheoilispresentafter20minutesofop-
eration.Iftheoilisfoamingexcessively after20minutesof
operation, check the refrigerant system for flood-back of
liquid refrigerant. Correct this situation before proceed-
ing.3. Checkthelevelofoilinthesightglasswiththecom-
pressor operating. The correct level should be 1/2 of the
sight glass. If the level is above 1/2, oil must be removed
fromthecompressor.Toremoveoilfromthecompressor,
followstepd.Ifthelevel isbelowthesightglass,addoilto
the compressor following step b.
b. AddingOilwithCompressorinSystem
1. Oil Pump Method
One compressor oil pump that may be purchased is a
Robinair, part no. 14388. This oil pump adapts to a one
U.S.gallon (3.785 liters) metal refrigerationoilcontainer
and pumps 2-1/2 ounces (0.0725 liters) per stroke when
connected to the oil fill (item 4, Figure 4-5). Also there is
no need to remove pump from can after each use.
When the compressor is in operation, the pump check
valve prevents the loss of refrigerant, while allowing ser-
vicemen to develop sufficient pressure to overcome the
operating suction pressure to add oil as necessary.
2. Closed system method
Inanemergencywhereanoilpumpisnotavailable,oil
maybedrawnintothecompressorthroughthesuctionser-
vice valve. CAUTION
Extreme care must be taken to ensure the
manifold common connection remains
immersed in oil at all times. Otherwise air and
moisture will be drawn into the compressor.
Connectthe suctionconnectionofthegaugemanifold
tothecompressorsuctionservicevalveport,andimmerse
thecommonconnectionofthegaugemanifoldinanopen
containerofrefrigerantoil.Crackthesuctionservicevalve
and gauge valve to vent a small amount of refrigerant
through the common connection and the oil to purge the
lines of air. Close the gauge manifold valve.
With the unit running, frontseat the suction service
and pull a partial vacuum in the compressor crankcase.
SLOWLY crack the suction gauge manifold valve and oil
will flow into the compressor. Add oil as necessary.
1
3
05K
4
6
2
5
1. Suction Service Valve
2.OilFillPlug
3. Oil Drain Plug
4. Oil Level Sight Glass
5. Unloader Solenoid
6. Discharge Service Valve
Figure 4-7. Compressor
c. Adding Oil to Service Replacement Compressor
Service replacement compressors may or may not be
shipped with oil.
If compressor is without oil
Add correct oil charge (refer to section 1.3) through
the suction service valve flange cavity or by removing the
oil fill plug. (See Figure 4-7)
d. To Remove Oil from the Compressor
1. Close suction service valve (frontseat) and pump
unit down to 2 to 4 psig (0.1 to 0.3 kg/cm2).STOPunit
frontseat discharge service valve and slowly reclaim re-
maining refrigerant.
2. Remove oil drain plug from the compressor and
drain the proper amount of oil. Replace the plug securely
in the compressor.
3. Open service valves and run unit to check oil level,
repeat as required to ensure proper oil level.

5-1
SECTION 5
ELECTRICAL
5.1 INTRODUCTION
This section includes the electrical wiring schematic for the DM-4 Power Pack.

5-2
Figure 5-1. Electrical Wiring Schematic Diagram --- DM-4 Power Pack
Dwg. No. 061-287 Rev C