HomeKohlerKohler 175REOZT4

Kohler 175REOZT4 Generator Set

The Kohler 175REOZT4 is a 30 kW (37.5 kVA) Diesel standby generator set powered by a Kohler 1.9L engine. It is available at 120/208 V, 277/480 V and 120/240 V, 3-phase, 60 Hz and rated 520 A. It holds about 28.5 L (7.5 gal) of oil and 35.6 L (9.4 gal) of coolant, with a maximum ambient rating of 45 °C. Starting uses 2 group-Two batteries rated 400 CCA at 24 V. The set measures 3993×1867×2206 mm (157.2×73.5×86.9 in), weighs about 1724 kg (3801 lb) and produces 66 dBA at 7 m. An integrated tank holds 293 L (77.4 gal), roughly 41 hours of runtime.

30 kW
Standby
1.9 L
Displacement
28.5 L
Oil capacity
5
Document types

How to read your Kohler serial & model number →

Typical fuel consumption for 30–35 kW Diesel generators →

Compare with other 30–35 kW Diesel generators →

Service parts for the 175REOZT4

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

Air intake

1 required

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

Specifications

FuelDiesel
Frequency60.0 Hz
Standby power30 kW
Standby kVA37
Prime power28 kW
EmissionsTier 4 Final
ControllerDecision-Maker 3500, Decision-Maker r 3500
Oil capacity28.5 L
Alternator4S12X
Voltage options120/208 V, 277/480 V, 120/240 V
Phase3 Ph
Rated current520 A
Circuit breaker150 A
Battery groupTwo
Battery cranking400 CCA
Battery voltage24 V
Battery quantity2
Coolant capacity35.6 L
Max ambient45 °C
Dimensions (L×W×H)3993×1867×2206 mm
Dry weight1724 kg
Sound level66.0 dBA @ 7 m
Fuel tank293.0 L
Tank runtime41 hr

Engine

Kohler 1.9L
Displacement1.9 L

Maintenance & consumables

for the Kohler 1.9L
ItemSpecCapacityPart #Interval
Air filterAir CleanerGM90735 Amazon eBay

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

What size generator is the Kohler 175REOZT4?

The Kohler 175REOZT4 is rated 30 kW standby (37.5 kVA).

What engine is in the Kohler 175REOZT4?

The Kohler 175REOZT4 is powered by the Kohler 1.9L engine.

What fuel does the Kohler 175REOZT4 use?

The Kohler 175REOZT4 runs on Diesel.

What alternator comes on the Kohler 175REOZT4?

The Kohler 175REOZT4 uses a 4S12X alternator.

What air filter does the Kohler 175REOZT4 use?

The Kohler 175REOZT4 uses air filter part number GM90735.

Parts

11
Part #DescriptionQtySystem
273377Gauge, restriction1Sensor Amazon eBay
A-226955Air cleaner assembly1Air filter Amazon eBay
GM16944Element, air cleaner1Air filter Amazon $71.53 eBay $49.68
GM22310Hose, Reducer1Hose Amazon eBay
GM66601Element, Inner1Air filter Amazon eBay $30.99
GM86224Hose, Air Intake (Item 5)1Hose Amazon eBay
GM88850Hose, Air Intake (Item 5)1Hose Amazon eBay
GM90735Air Cleaner1Air filter Amazon eBay
GM91358Element, Air Cleaner1Air filter Amazon eBay
GM91647Hose, Hump1Hose Amazon eBay
GM92823Element, Air Cleaner Safety1Air filter Amazon eBay

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
Prime3.00.8
Prime25%12.13.2
Prime50%10.22.7
Prime75%13.23.5
Prime100%38.610.2
Standby3.00.8
Standby25%13.23.5
Standby50%22.335.9
Standby75%32.38.5
Standby100%42.411.2

Available documents

Spec sheet — Towable Mobile Generators Brochure (Kohler)Spec sheet — g5419 (Kohler)Reference — Mobile Rental Generators (Kohler)Owner's manual — tp6895 (Kohler)Parts manual — tp6894 (Kohler)Service manual — sb771 (Kohler)Service manual — tt1672 (Kohler)Service manual — tt771 (Kohler)
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