PRESSURE WASHER: Cleans dirty surfaces with high pressure water.
To the Owner:
Thank you for purchasing a Northstar pressure washer. Your machine is designed for long life, dependability,
and the top performance you demand! Take time now to read through this manual so you better understand the
machine’s operation, maintenance and safety precautions. Everyone who operates this machine must read and
understand this manual. The time you take now will prolong your machine’s life and prepare you for its safe
operation. Enjoy the exceptional performance of your Northstar pressure washer, the industry leader! The
manufacturer reserves the right to make improvements in design and/or changes in specifications at any time
without incurring any obligation to install them on units previously sold.
Pump Oil Pump is shipped with oil. Change oil plug and check pump oil level before starting.
Use SAE 30 Non-detergent pump oil (item# 4043) or Cat Pump oil (item# 22158) for oil
changes.
Water Make sure your water flow is 20% higher than the pressure washer’s flow rate.
Make sure your water is clean and particle free.
Storage Do not allow water to freeze in the pump, hose, or spray gun.
Spraying
Chemicals
Maintenance
Schedule
Hours: Monday - Friday 7:00 AM to 5:30 PMUnit 2, Keel Close,
Use any North Star brand or equivalent pressure washer chemicals.
Adjust soap adjustment knob to regulate cleaning power.
Pump: Oil: change after first 50 hours, then every 3 months or 500 hours.
Read and understand all manuals before operating.
Any Questions, Comments, Problems or Parts Orders
In the United States In the United Kingdom
Northstar Customer Service
Call 1-800-270-0810 Northern Tool and Equipment Co. (UK) Ltd.
Saturday 7:30 AM-11:30 AM Central Time Portsmouth, Hants PO3 5QD, England
Call 02392639752
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Table of Contents
Important Safety Instructions 2 Maintenance Instructions 10-11
Grounding Instructions 2 Long Term Storage 11
Machine Component Identification 3 Troubleshooting 12
Installation Instructions 4-7 Parts Breakdowns 12-17
Operating Instructions 8-10 Wiring Diagram 18
Important Safety Instructions
WARNING -Risk of Injection or Injury to Persons - Do Not Direct Discharge Stream at Persons. - Do not use a hose if
exterior damage is evident.
-Risk of explosion. - Do not spray flamm a ble li qui d s. - Do not o perat e i n a flam m a bl e envi ro nment.
CAUTION-Gun kicks back. Hold with both hands.
-To reduce the risk of injury, read operating instructions carefully before use.
WARNING - When using this product basic precautions should always be followed, including the following:
1.) Read all the instructions before using the product.
2.) To reduce the risk of injury, close supervision is necessary when the product is used near children. Do not allow
irresponsible use by children. Always stop the product and bleed pressures before leaving unattended,
disconnecting hoses, or servicing the pump.
3.) Know how to stop the product and bleed pressures quickly. Be thoroughly familiar with the controls.
4.) Stay alert - watch what you are doing.
5.) Do not operate the product when fatigued or und er the influence of alcohol or drugs. Never smoke while operating
this machine.
6.) Keep operating area clear of all persons.
7.) Do not overreach or stand on unstable support. Keep good footing an d balance at all times. Wear footwear capa ble
of maintaining a good grip on wet surfaces - Do not place the machine on soft or unstable ground.
8.) Follow the maintenance instructions specified in all manuals. Do not run machine without sufficient lubrication or
sufficient water to cool the pump.
9.) Wear safety glasses, gloves, face protection and appropriate clothing when operating the machine.
10.) Do not operate this machine with broken or missing parts. - Never alter the manufacturer’s original design or
deactivate any safety device on the machine.
11.) Risk of exposure to dangerous chemicals. Wear protective gloves when handling and cleaning with chemicals.
Follow the chemical manufacturer’s directions. Understand all safety hazards and first aid for all chemicals being
used. Check whether dangerous chemicals have been used and take any precautions that may have been
recommended by the supplier of these chemicals when cleaning filters. Do not pump highly abrasive fluids or use
with incompatible chemicals or solvents.
12.) Know the pressure and temperature limits of your machine. Be sure all high pressure accessories meet or exceed
your machine’s limits. Do not set the pressure relief valve above the machine’s limit.
13.) Do not move this machine by pulling on the hose. Do not use the pump to support other items of equipment that
impose unacceptable loads on the pump. Do not attempt to use this machine as a prop.
14.) To reduce risk of injury, do not secure the spray gun open. Your spray gun is equipped with a built-in trigger safety
latch to guard against accidental trigger release and potentially dangerous high pressure spray. Rotate the safety
latch to the locked position when not spraying.
15.) Do not clean this machine with its own spray. Cleaning should be done with a damp sponge with the electrical
power turned OFF.
Grounding Instructions
This product must be connected to a grounded, metal, permanent wiring system; or an equipment-grounding conductor must be run
with the circuit conductors and connected to the equipment-grounding terminal or lead on the product.
SAVE THESE INSTRUCTIONS
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Machine Component Identification
157303/157304
Ref # Description Ref # Description
1 Inlet/Filter 4 Pump
2 On/Off Switch 5 Unloader
3 High Pressure Outlet 6 Motor
fig02288
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Installation Instructions
I.) Unpack
Separate and identify all components. Use the assembly instructions in this manual for assembly.
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HARDWARE BAG: Separate and identify all components. Use the assembly instructions in this manual for assembly.
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II.) Assembly Instructions
A. 1. To spray chemical, insert the chemical injector into the
quick connect oulet o f the pressure washer as shown.
2. Connect the clear hose to the chemical strainer and to
the inlet of the chemical injector. This is inside the base
unit on the 157303, chemical injector can remained
installed at all times. Have hose exit base as shown
below.
3. Install the pressure hose onto the chemical injector as
shown, for 157304. Install on quick connect outlet on
157303.
4. Connect the other end of the pressure hose to the spray
gun as shown.
5. Connect the lance extension to the spray gun and insert
the proper nozzle into the lance end.
6. Make sure all plumbing connections are tight.
Nozzle
Lance
Extension
Spray
Gun
Quick Connect
Outlet
7. Install four rubber feet onto base with four 1/4” x 3/4”
flange bolts and four flange nuts. Use the same bolts to install
cross members when installing the rubber feet.
High Pressure
Hose
Chemical
Injector
157304 only
Chemical Hose
Exit for 157303
Clear
Hose
Chemical
Strainer
RUBBER FEET
FIG0235
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III.) Wiring Instructions
This pressure washer is shipped without a power cord and is
intended to be hard wired into your electrical system. The
following instructions will help you to hard wire this unit.
Electrical Requirements:
Item Number Circuit Rating
157303 115V/20A
157304 230V/30A
WARNING: Make sure to use a dedicated circuit that
includes a GFCI. Consult local electrical code for
connection requirements.
A 157304 is shown in the following steps, the 157303 gets
wired the exact same way.
Step 1: Using a 3/8” wrench, remove the roof and the top of
the electrical housing. (Front panel not shown for clairity.)
Step 3: Locate terminal block inside the electrical housing and
attach wires (like colors should be across from each other).
Step 4: Clamp cord in strain relief nut (thru the bottom of the
panel) by turning nut clockwise.
Step 5: Re-attach the top of the electrical housing and the
roof.
Step 2: Feed power cord through the strain relief nut on the
bottom of the unit into the electrical housing.
POWER SUPPLY CORD
OR CONDUIT
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Operating Instructions
Read and understand the entire manual before operating the pressure washer.
Follow these instructions every time you use the pressure washer.
I.) Pre-Operation
; A.) Position the machine for easy access to all controls.
; B.) Position the machine on a solid surface, with less
than a three degree slope, and so it is protected from
external damage.
; C.) Make sure ambient lighting is sufficient for the
surface you are cleaning to be seen with ease. Use
artificial light if needed.
; D.) Check hoses, fittings, wand, trigger gun and electrical
cords for signs of wear, cracks and looseness, and
replace as required.
; E.) Check and clean the nozzle orifice.
; F.) Check and clean the water inlet screen and filter.
; G.) Read entire manual, especially the important safety
instructions listed on page 2.
; H.) Check and maintain proper oil levels in the pump.
II.) Check Your Water Supply
; A.) Make sure the water supply is clean. Debris can
cause excess pump wear and reduce performance.
; B.) An insufficient water supply will damage your pump.
Make sure the water supply is steady and is 20% over
the rated flow of your pump. Use a stopwatch to
time how long it takes to fill a 5 gallon bucket with
your garden hose.
Example: If the rated flow is = 3gpm
Then required flow = 3 x 1.20 = 3.6gpm
5gallons / 3.6gpm = 1.39 minutes
1.39min x 60sec/min = 83 seconds
Therefore, you must be able to fill a
5 gallon bucket in 83 seconds or faster.
; C.) The water supply garden hose must have an inside
diameter of at least 5/8”. If the hose is more than 100
ft. long, the diameter must be at least 3/4”.
; D.) Never use a reservoir tank as a water source. This
pressure washer is designed for a pressurized water
source such as a city water faucet. Sucking water out
of a tank may cause pump cavitation and damage to
your pump. However, the inlet pressure of the pump
must not exceed 115 psi (8 bar).
; E.) Always use a flexible rubber hose for your water
supply. Do not use rigid piping.
; F.) Do not pump flammable liquids or liquids containing
incompatible chemicals or solvents.
III.) Before Starting
WARNING: Check hoses, fittings, wand, gun and cords
daily for signs of wear, cracks and looseness, and replace as
required.
1. Connect water supply hose to the garden hose
connector located on the side of the unit.
2. Connect high pressure hose to quick connect outlet
on front of the machine.
3. Connect spray gun to high pressure hose.
4. If detergents will be used, only use detergents
intended for pressure washers. Follow instructions
on the detergent container.
IV.) To Start
DANGER: Do not point the spray wand at yourself or at any
person. Bodily injury may result from water under high
pressure.
WARNING: Wear eye, ear, hand, foot and skin protection at
all times while operating this pressure washer.
IMPORTANT: The water must be turned on before starting.
Running the pump dry will cause damage and void warranty.
1. Turn water supply ON.
2. Squeeze the trigger to allow air to purge from the system.
(this step goes faster with the pressure nozzle removed)
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V.) Attach Nozzle
N
ozzle
00663
Color of Nozzle:
Red 0 Highest Impact
Yellow 15 Tough Stains/
Green 25 General
White 40 Light Cleaning
Black Low pressure/
Spray Angle Used For:
Stripping
Chemical
Application
Your pressure washer is equipped with five nozzles. To install
a nozzle simply pull back the collar and push the nozzle into
the coupler. Once the connection is made, pull on the nozzle to
assure a tight connection.
Lance
Nozzle
CORRECTINCORRECT
WARNING: Make sure the nozzle is correctly
inserted. The nozzle may become a projectile if not
inserted correctly. Do not attempt to use different
types of nozzles that may not fit the coupler.
Collar
Coupler
VI.) Turn the pump switch ON.
1. Make sure the hose is not kinked. A kinked hose
will provide insufficient water supply to the pump and
will reduce its life.
To Clean
WARNING: Wear eye, ear, hand, foot and skin protection at
all times while operating this pressure washer.
DANGER: Do not point the spray wand at yourself or
at any person. Bodily injury may result from water
under high pressure.
IMPORTANT: Your spray gun is equipped with a built-in
trigger safety latch to guard against accidental trigger
actuation and potentially dangerous high pressure spray.
Rotate the safety latch to the locked position when not
spraying.
NOTE: Your pressure washer is equipped with a low
pressure chemical injector. You do not need to use
chemicals for every job, however, the proper chemical used
for the proper application can speed up cleaning jobs
tremendously.
WARNING: Only use North Star pressure washer chemicals
or chemicals specifically formulated for pressure washers.
Follow the chemical manufacturer’s recommendations.
Understand all safety precautions and first aid for all
chemicals.
1. Insert chemical suction line and strainer into a
2. Completely open the chemical control knob located
3. Insert the chemical application nozzle (Black).
4. Turn the chemical control knob to adjust the
5. Change back to high pressure by inserting the
6. Hold the lance with two hands, have a sturdy stance.
7. Point lance at dirty surface and squeeze trigger.
8. Wash from the bottom to the top, using side to side
9. Use the width of the spray pattern to wash in a wide
10. The nozzle should be 12” to 24” from the work,
Max Chemical Ratio is 13:1
Caution: Be careful on painted or delicate surfaces,
the pressure may damage the surface if the nozzle is
too close.
11. Small parts should be washed in a basket so the
12. The pressure washer is set to the maximum rated
container of detergent.
on the chemical injector.
chemical concentration. Spray detergent onto the
surface and allow it to soak. Chemicals need time
(dwell time) to work properly. Follow the chemical
manufacturer’s recommendations for dwell time.
nozzle with the desired spray angle.
motions. This washes away heavy dirt and allows
the detergent to soak as you work toward the top.
path. Overlap spray paths for complete coverage.
closer for tough areas.
pressure does not push them away. Larger, light
weight parts should be clamped down.
pressure when it leaves the factory. To change your
pressure, turn the unloader knob found inside the
machine counter clockwise.
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WARNING: Do not alter the unloader valve’s maximum
k
pressure. Excess pressures could cause serious injury and/or
pump damage. Any alteration other than turning the
adjustment knob will void your warranty.
Maintenance Instructions
WARNING: Unauthorized machine modification or use of
non-approved replacement parts may cause personal injury
and/or property damage and will void the manufacturer
warranty.
All mechanical equipment, no matter how well designed, will
need repairs. A North Star pressure washer is no exception. At
times, a North Star pressure washer may be inoperable because
repairs are required. North Star Customer Service will assist in
these repairs as needed, but if an inoperable pressure washer
creates a major expense to your business then we strongly
recommend the following:
1. Have someone on staff who is trained in the operation of the
pressure washer and is capable of making minor repairs and
performing all preventative maintenance procedures as
outlined in the provided manuals.
2. Keep a stock of recommended service parts for maintenance
and minor repairs.
Recommended Service Parts List
Following is a list of the service parts we recommend stocking.
Description Part Number
Nozzle 5 Pack (157303) 778197
Nozzle 5 Pack (157304) 778281
O-Ring for Hose 30784
Pump Oil 4043
Chemical Injector 31935
Spray Gun 319153
50’ Pressure Hose 32276
Maintenance Mode
Before performing any maintenance on the pressure washer, it
must be placed in maintenance mode.
A.) Turn off water supply
B.) Bleed water from system
C.) Disconnect power by unplugging power cord and/or
flipping circuit breaker OFF.
To Stop
1. If detergents were used, draw clean water through the
2. Turn the pump switch OFF.
3. Turn OFF the water supply.
4. Squeeze the trigger to relieve the system pressure.
detergent inlet line to purge detergent. Failure to do
so may clog the chemical injector.
Maintenance Schedule
What to Check When To Check What to Do
Inlet Filter Each Use Clean
Hoses Each Use Check for Wear
Bolts Each Use Check for Loose
Bolts
Cleaning The Inlet Filter
WARNING: Check whether dangerous chemicals have been
used, and take precautions when handling filters.
A.) Unscrew inlet filter cap
B.) Re move Inlet filter
C.) Run water though to clean filter
Checking the Hoses
WARNING: Do not use a finger or skin to check for leaks.
Escaping fluid under pressure has sufficient force to
penetrate the skin, causing serious injury. Do not operate the
pressure washer if the hose is cracked, worn, or leaking.
A.) Check all hoses for leaks
B.) Check all hoses of worn areas
Good
Bad
Water Lea
Wire Mesh
Bad
00426
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Changing The Pump Oil
Change oil after first 50 hours, then every 3 months or 500
hours
1.) Remove oil drain plug
2.) Drain pump oil
3.) Replace oil drain plug
4.) Fill pump with Cat Item# 22158 pump oil.
5.) Fill half way up the sight glass.
Quantities Of Fluid
Pump Type of Fluid QTY
Cat 2DX15ES SAE 30** 8.5oz (0.25L)
CAT 5CP3120 SAE 30** 17.0oz (0.41L)
During cold weather, store the pressure washer indoors and move it outdoors before starting the motor.
Follow these instructions to prevent the pump from freezing during storage.
Storage:
Before you store the pressure washer, make sure you do the
following:
1.) Unplug the power cord from the pressure washer.
2.) Disconnect high pressure and garden hose.
Winter Storage:
Items needed: 12” piece of garden hose or equivalent, funnel
and RV antifreeze (approximately 6 oz.)
1.) Follow the storage instructions listed above.
2.) Attach the garden hose with funnel to the pump inlet (see
illustration).
3.) Pour RV antifreeze into the funnel, turn on the motor until
antifreeze comes out the pump outlet.
4.) Drain all water from the high pressure hose. Depress trigger
on gun and drain all water out of gun/lance.
Oil Sight Glass
Oil Cap
(remove tape)
Oil Sight Glass
Oil Drain Plug
Water Inlet
),*
RV Antifreeze
Funnel
Hose
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Troubleshooting Guide
Pressure Washer Will Not Run At All - No Power
Causes Solutions
Machine turned OFF Turn Pump switch ON
Line circuit breaker tripped Check for tripped circuit breaker in building
Circuit Breaker Trips
Causes Solutions
Voltage too low Check the voltage
Circuit Breaker Overloaded Make sure there is no other equipment using the same circuit.
Pressure set too high Check/adjust pressure setting on unloader.
Pressure Washer Runs But Will Not Spray Water
Causes Solutions
Trigger released Squeeze trigger
Clogged nozzle Clean nozzle orifice
Low Pressure
Causes Solutions
Low water flow Make sure the water supply is more than 4 gpm
Partially clogged or damaged nozzle Clean or replace nozzle
Pressure Washer Runs But Surges Or Cycles While In Bypass
Causes Solutions
Leak between unloader and gun. Check all connections between unloader and gun for leaks. Tighten loose
components and replace damaged components.
Gun leaking internally Replace spray gun
Poor Or No Detergent Supply
Causes Solutions
Soap control knob set too low. Adjust soap control knob
Inadequate detergent supply Refill detergent container. Make sure the chemical strainer is fully submerged
High pressure hose too long Use less hose. Move machine closer to the work.
Chemical strainer or hose clogged Clean the strainer. Always start with a clean detergent container
Clogged injector Clean injector check valve or replace injector. Run clean water through the injector
after each use.
Any Questions, Comments, Problems or Parts Orders
In the United States In the United Kingdom
North Star Customer Service
Call 1-800-270-0810 Northern Tool and Equipment Co. (UK) Ltd.
Hours: Monday - Friday 7:00 AM to 5:30 PM Unit 2, Keel Close,
Saturday 7:30 AM-11:30 AM Central Time Portsmouth, Hants PO3 5QD, England