HomeKohlerKohler 55REOZT4

Kohler 55REOZT4 Generator Set

The Kohler 55REOZT4 is a 47 kW (58 kVA) Diesel standby generator set powered by a Kohler KDI 3404TCR engine. It is available at 120/208 V, 120/240 V, 277/480 V and 347/600 V, 3-phase, 60 Hz and rated 164 A. It holds about 15.1 L (4.0 gal) of oil and 12 L (3.2 gal) of coolant, with a maximum ambient rating of 45 °C. Starting uses 1 group-One battery rated 925 CCA at 12 V. The set measures 2506×1120×1896 mm (98.7×44.1×74.6 in), weighs about 1989 kg (4385 lb) and produces 69 dBA at 7 m. An integrated tank holds 386 L (102.0 gal), roughly 24 hours of runtime. The same KDI 3404TCR engine also powers generator sets from Lombardini and Valdinoci.

47 kW
Standby
3.359 L
Displacement
15.1 L
Oil capacity
5
Document types

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Typical fuel consumption for 45–50 kW Diesel generators →

Compare with other 45–50 kW Diesel generators →

Service parts for the 55REOZT4

Grouped by system, with how many of each the parts manual calls for.

Air intake

1 required
GM93824Air filtersee priceAmazon

Prices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.

Specifications

FuelDiesel
Frequency60.0 Hz
Standby power47 kW
Standby kVA58
Prime power42 kW
EmissionsTier 4 Final
ControllerDecision-Maker 3500, Decision-Maker r 3500
Oil capacity15.1 L
Alternator4P8X (4-pole, Class H insulation)
Voltage options120/208 V, 120/240 V, 277/480 V, 347/600 V
Phase3
Rated current164 A
Circuit breaker250 A
Battery groupOne
Battery cranking925 CCA
Battery voltage12 V
Battery quantity1
Coolant capacity12.0 L
Max ambient45 °C
Dimensions (L×W×H)2506×1120×1896 mm
Dry weight1989 kg
Sound level69.0 dBA @ 7 m
Fuel tank386.0 L
Tank runtime24 hr

Engine

Kohler KDI 3404TCR
Oil capacity15.6 L
Coolant capacity12.0 L
Displacement3.359 L
AspirationTurbo+ Charge After Cooler
Rated speed1800 rpm

Maintenance & consumables

for the Kohler KDI 3404TCR
ItemSpecCapacityPart #Interval
Air filterAir Cleaner AssyGM93824 Amazon eBay
Fuel filterWater sensor12000 hr
Oil filter12000 hr
Battery2000 hr
Belt5000 hr
Coolant40000 hr
Coolant filterAn anti-freeze protection liquid (ANTIFREEZE) - mixed with decalcified water - must be used.500 hr
OilAPI CK-4 / API CJ-4 / ACEA E6 E7 E915.6 L2000 hr
Spark plug5000 hr

Service intervals

2
ItemActionHoursMonthsNotes
Paralleling boxInspect12 moAnnually by a Kohler authorized distributor/dealer, or when wear, damage, deterioration, or malfunction is evident or suspected.
Paralleling box internal componentsInspect1 moMonthly or when a condition noticed during external inspection may have affected internal components; enclosure cover must be removed by trained personnel.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

6
TypeItemValueUnitCondition
OtherEngine speed adjustment50default setting; settings between 40 and 60 acceptable; 52 increases speed by 2 RPM, 49 decreases by 1 RPM
OtherGenerator to bus phase angle-10 to 10degreesverify with contactor closed
OtherReactive droop1%default setting; range 0.5 - 2%
TorquePGEN terminal block connections0.5Nm
TorquePGEN terminal block connections4.4in. lbs.
VoltageController measurement accuracy2%without calibration; requires a calibrated multimeter for calibration

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

12
Calibration adjustment

⚠ Copying personality profiles from one controller to another can overwrite calibration coefficients and requires re-calibration.

Tools: Calibrated multimeter with recent calibration verification

  1. Use a calibrated multimeter to measure the generator voltage and enter the correct value in the CONTROLLER CONFIG -> CALIBRATION screen.
  2. Use a calibrated multimeter to measure the bus voltage and enter the correct value in the CONTROLLER CONFIG -> CALIBRATION screen.
Verify Generator Operation diagnostic

⚠ Generators must all operate at the same frequency, voltage, and phase connection in order to parallel.

Tools: SiteTech software

  1. Ensure the load is not connected or is drawing less power than a single generator can provide.
  2. Navigate to CONTROLLER CONFIG -> COMMUNICATION SETUP and verify PGEN Nodes Online indicates the correct number of nodes.
  3. Verify alternator connection (voltage selector switch position), system voltage, and voltage regulator target on each generator.
  4. Start a single generator by pressing the Run button; the paralleling box contactor should close and the Generator Connected to Bus indicator should light.
  5. Verify bus and generator voltages match and generator to bus phase angle is between -10 and 10 degrees.
  6. Verify the load bus is energized and available at the load.
  7. Stop the generator by pressing the OFF button; the contactor should open.
  8. Repeat for each generator in the paralleling system.
Verify Paralleling and Load Sharing diagnostic

Tools: Load bank (optional)

  1. Place all generators in automatic mode by pressing the Auto button; verify the red shutdown indicator is not illuminated.
  2. Provide a local start request by holding AUTO, pressing RUN, releasing RUN, then releasing AUTO.
  3. Verify all generators start, one generator closes its contactor, and the others synchronize and close their contactors.
  4. Verify that the % of rated power of the generators matches, showing the generators are sharing load equally.
  5. If a load bank is available, test the system under load.
Control Harness Connections installation

⚠ The control harness connections for GEN 1 and GEN 2 must correspond to the source camlock cable connections.

  1. Connect the control harness from the generator set connected to the GEN 1 camlock connectors to GEN 1 CONTROL.
  2. Connect the control harness from the generator set connected to the GEN 2 camlock connectors to GEN 2 CONTROL.
  3. When not used, store the control harnesses on the storage rack inside the enclosure.
Grounding installation

⚠ Grounding electrical equipment: hazardous voltage can cause severe injury or death. Turn off the main circuit breakers of all power sources before servicing.

  1. Connect the ground lug on the paralleling box to earth ground according to applicable state and local codes.
  2. Follow NEC guidelines for grounding electrical equipment.
  3. The neutral is bonded to ground inside the paralleling box; if required, remove the bonding bus to disconnect neutral from ground.
Load Connections installation

⚠ Multiple power sources can automatically energize the distribution bus. Disconnect all power sources before connecting to the distribution bus.

  1. Remove the camlock security guard from one row of connectors for each generator and store the guard.
  2. Connect the load side ground (green) camlock cables to the distribution bus and then to the paralleling box.
  3. Connect the load side neutral (white) camlock cables to the distribution bus and then to the paralleling box.
  4. Connect the load side L1 (black), L2 (red), and L3 (blue) camlock cables to the distribution bus and then to the paralleling box.
Multiple Paralleling Boxes (PGEN Connections) installation
  1. Connect one or two generators to each paralleling box.
  2. Use Belden cable #9841 (or equivalent) shielded twisted-pair communication cable to connect the PGEN terminal blocks on the paralleling boxes.
  3. Tighten the connections to 0.5 Nm (4.4 in. lbs.).
Paralleling System Setup installation

⚠ Generator management must be disabled manually at each generator set controller.

Tools: Personal computer with SiteTech software

  1. Check that the voltage selector switch and/or alternator wiring matches the building voltage configuration for all generator sets.
  2. Set the digital output to Contactor (SiteTech Programmable Digital Output 116).
  3. Set reactive droop to 0.5-2% (default 1%), using the same reactive droop setting on all generators.
  4. Set the target voltage on all paralleled generators to the same value.
  5. Set engine speed adjustment to 50 on all generators (default 50; range 40-60).
  6. Verify metering; if voltage is incorrect, use the calibration procedure.
  7. Set Sync Mode in AUTO to ACTIVE and Sync Mode in Run to CHECK on all generators.
  8. Set Generator Management Enabled to OFF at each generator unless generator management is requested.
  9. Set up load management (load shed priorities) for non-critical loads.
  10. Stop all generators by pressing the OFF button on each controller.
Source Connections installation

⚠ Hazardous voltage. This equipment must be installed and serviced by qualified electrical personnel. Do not connect or disconnect cables under load.

  1. Remove the camlock security guard from one row of connectors for each generator and store the guard.
  2. Generator 2 connects to the upper set of camlocks; generator 1 connects to the lower set.
  3. Connect the source side ground (green) camlock cables to the paralleling box first and then to each generator.
  4. Connect the source side neutral (white) camlock cables to the paralleling box first and then to each generator.
  5. Connect the source side L1 (black), L2 (red), and L3 (blue) camlock cables to the paralleling box first and then to each generator.
Storage Procedure maintenance

⚠ Do not open the electrical compartment on the opposite side of the enclosure; that compartment should be opened only by Kohler authorized distributors or dealers.

  1. Store control harnesses on the storage rack inside the box when not in use.
  2. Lock the cabinet door with the key provided and store the key in a secure location.
  3. Use the guards to cover the camlock connectors.
  4. Attach padlocks to the electrical panel cover and the camlock guards to prevent unauthorized access.
Disable the Generator Sets operation

⚠ Accidental starting can cause severe injury or death. Remove the negative (-) lead first when disconnecting the battery; reconnect it last.

  1. Press the generator set master control OFF/RESET button.
  2. Disconnect the power to the battery charger, if equipped.
  3. Disconnect the generator set engine starting battery(ies), negative (-) lead first.
Re-enable the Generator Sets operation

⚠ Reconnect the battery correctly, positive to positive and negative to negative, to avoid electrical shock and damage.

  1. Check that the generator set is OFF.
  2. Reconnect the generator set engine starting battery, negative (-) lead last.
  3. Reconnect power to the battery charger, if equipped.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Common questions

How many kW is the Kohler 55REOZT4?

The Kohler 55REOZT4 is rated 47 kW standby (58.0 kVA).

What engine does the Kohler 55REOZT4 use?

The Kohler 55REOZT4 is powered by the Kohler KDI 3404TCR engine.

What kind of fuel does the Kohler 55REOZT4 run on?

The Kohler 55REOZT4 runs on Diesel.

What is the oil capacity of the Kohler 55REOZT4?

The Kohler KDI 3404TCR engine in the Kohler 55REOZT4 has an oil capacity of 15.6 liters.

What alternator comes on the Kohler 55REOZT4?

The Kohler 55REOZT4 uses a 4P8X alternator. It has 4 poles. Insulation class H.

Which air filter part number does the Kohler 55REOZT4 take?

The Kohler 55REOZT4 uses air filter part number GM93824.

Parts

42
Part #DescriptionQtySystem
8010710020CRANKSHAFT1Crankshaft Amazon eBay
8011710030PISTON / CONNECTING ROD2Piston connecting rod Amazon eBay
8012710050FLYWHEEL1Flywheel Amazon eBay
8014710050PULLEYS / BELT2Pulleys belt Amazon eBay
8020710090CRANKCASE1Crankcase Amazon eBay
8021710070CYLINDER HEAD1Cylinder head Amazon eBay
8022710080HEAD COVER1Head cover Amazon eBay
8025710010ENGINE MOUNTS8Engine mounts Amazon eBay
8030710150INJECTION SYSTEM1Injection system Amazon eBay
8035710090CAMSHAFT2Camshaft Amazon eBay
8036710070ROCKER ARMS / VALVES16Rocker arms valves Amazon eBay
8038710050TIMING GEAR3Timing gear Amazon eBay
8040710030OIL PUMP4Oil pump Amazon eBay
8041710040OIL PAN1Oil pan Amazon eBay
8043710020OIL DIPSTICK1Oil dipstick Amazon eBay
8045710050BREATHER SYSTEM2Breather system Amazon eBay
8061710010FUEL FILTER1Fuel filter Amazon eBay
8061710020FUEL FILTER1Fuel filter Amazon eBay
8068710070HOSES FOR WATER COOLER2Hoses water cooler Amazon eBay
8074710030THERMOSTAT UNIT1Thermostat unit Amazon eBay
8077710030WATER PUMP1Water pump Amazon eBay
8079710010FITTING FOR CAB HEATING1Cabin heating fitting Amazon eBay
8080710050AIR INLET MANIFOLD / AIR FILTER2Air inlet manifold filter Amazon eBay
8083710060TURBOCHARGER1Turbocharger Amazon eBay
8085710090EXHAUST GAS MANIFOLD2Exhaust gas manifold Amazon eBay
8086710020EXHAUST MUFFLER2Exhaust muffler Amazon eBay
ED0053030050Air filter cartridge1Air filter Amazon eBay
GM93824Air Cleaner Assy1Air filter Amazon eBay
GM93996Element, Air Cleaner Primary1Air filter Amazon eBay
GM93997Element, Air Cleaner Secondary1Air filter Amazon eBay
8011710040PISTON / CONNECTING ROD4Service part / kit Amazon eBay
8020710100CRANKCASE1Service part / kit Amazon eBay
8021710080CYLINDER HEAD4Service part / kit Amazon eBay
8022710070HEAD COVER4Service part / kit Amazon eBay
8030710130INJECTION SYSTEM4Service part / kit Amazon eBay
8035710120CAMSHAFT1Service part / kit Amazon eBay
8036710080ROCKER ARMS / VALVES16Service part / kit Amazon eBay
8038710040TIMING GEAR3Service part / kit Amazon eBay
8045710070BREATHER SYSTEM2Service part / kit Amazon eBay
8047710030OIL COOLER1Service part / kit Amazon eBay
8064710030FUEL PIPING1Service part / kit Amazon eBay
ED0014603650-SSix Nicks SN8Service part / kit Amazon eBay $58.64

Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.

Fuel consumption

RatingLoadL/hgal/h
Prime1.50.4
Prime25%3.20.8
Prime50%6.41.7
Prime75%9.62.5
Prime100%12.93.4
Standby1.50.4
Standby25%4.61.2
Standby50%7.572.0
Standby75%10.92.9
Standby100%14.23.8

Available documents

Spec sheet — g5414 (Kohler)Reference — 55REOZT4 October 2015 (Kohler)Reference — DieselMobileGenerator (Kohler)Reference — Mobile Rental Generators (Kohler)Reference — adv9174 (Kohler)Owner's manual — tp6895 (Kohler)Parts manual — tp6894 (Kohler)Service manual — tt1672 (Kohler)
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