Worn or incorrect nozzle

Replace with nozzle of correct size

Unloader is by-passing

Check for seal at ball and seat
Check for broken components
Adjust unloader for pressure increase

Insufficient inlet supply

Ensure water is on
Check for correct hose I.D.
Check for plugged screen/filter
Purge hose for gravity-fed systems

Fouled or dirty valves

Check and replace if needed

Plunger(s) not moving or seized

Fix or replace broken or disconnected bearing(s) / connecting rod(s)

Belt slippage

Tighten or replace with correct belt

Excessive water leakage

Reseal or replace damaged fittings and hoses

Pump not turning

Check for key in shaft
Replace or install if needed
Check for belt slippage
Tighten or replace with correct belt

Inlet valves dammaged or broken

Check for damage and replace if needed

No nozzle

Install correct size nozzle

Water spraying out in all direction around the spray tip

Replace the coupler O Ring

Unloader over-adjusted

Back unloader adjustment out

Unloader by-passing

Check ball and seat and replace if necessary

RPM on motor is too low

Adjust RPM to 3550 without load

Throttle control valve

Check operation and ensure unit is getting to 3550 RPM

No by-pass valve

Install correct components

By-pass valve not sealing

Check for wear and dirt
Clean and replace as necessary

Leak in discharge system

Check hose, couplings and gun for water leaks

Restricted inlet or air entering the inlet plumbing

Check inlet plumbing for water or air leaks
Check inlet screen/filter
Clean and replace if needed

Stuck inlet or discharge valves

Check valves and replace if needed

Mechanical damage in crankcase

Check plungers, connecting rods, bearings and crankshaft for damage, and replace if needed

Inlet water is too hot

Reduce temperature below 63°C (145°F)

Nozzle is clogged

Clean nozzle or replace

Worn packings

Check and replace if needed

Dirt in unloader

Disassemble and clean
Replace any damaged parts

Valves are clogged with dirt or broken springs

Clean valves or replace

Worn Packings

Check and install new seals as needed

Loose fittings

Seal or tighten fittings

Scored plungers

Check and replace if needed

Worn oil Seals

Check and install new seats if needed

Worn or scored plungers

Replace if needed

Unmasked size on spacer rings

Check rings with a straight-edge and replace if needed

Plungers running sideways

Check for undue stress on plungers

Overflowing oil

Look for traces of oil on top
Check sight glass for overfull

Worn crankshaft seal or improperly installed O-Ring / oil seal

Remove oil seal and replace damaged O-Ring / oil seal

Bad bearing

Check and replace as needed

Loose cracked drain plug/sight glass

Check and tighten or replace

High humidity

Change pump oil

High inlet pressure

Test inlet pressure and install regulator if needed

Worn Seals

Check oil seals for wear and replace seals as needed

Water splashing on top of pump

Operate under cover if rain
Avoid spraying top of pump

Plungers worn

Check for scoring and replace if needed

Scored plungers

Check and replace as needed

High inlet pressure

Reduce pressure to pump

High RPM

Adjust RPM to specifications

Excessive temperature

Ensure pumped fluids are below 63°C (145°F)

Unloader is over-adjusted

Re-adjust unloader to specifications

Abrasive material in pumped fluids

Install proper filter on water supply

Running pump dry

Do not run pump without water

Wrong nozzle

Ensure soap nozzle is used

Adjustment closed

Open metering valve

Plugged orifice in body

Remove and clean or soak in warm water

Plugged filter

Replace or soak in water water to clean

Ball and cone spring damaged or missing

Remove barb and clean or replace and install

Fouled or dirty inlet or dishcarge valves

Remove dirt from valves and manifold. Replace if needed

Damaged low pressure seals (Triplex)

Replace damaged seals
Check for scoring on plungers

Plunger(s) not moving

Fix or replace broken or disconnected bearing(s)/connecting rod(s)

Faulty pulsation damper

Check precharge, recharge if low
Replace if needed

No key in keyway and friction causes pump to turn slightly

Check to ensure key is properly located

Wrong nozzle tip is being used

Change tip to black soap tip.

Incorrect chemical injector metering valve position

Make sure the chemical injector metering valve (brass valve located on the pump where the clear vinyl tubing is attached) is in the middle position. Turning the valve all the way to the right "clockwise" turns the soap off - Turning the valve "counter clockwise" opens the valve to full open position.

Chemical injector hose is not submerged

Make sure chemical injector hose is submerged into liquid soap or water and try the test again.

Faulty gun

Turn everything off and remove wand. Turn water back on and test for soap. If there is soap the gun need to be replaced.

Problem with injector

If the injector used to work but has recently stopped after not using the machine for a while you may have the ball stuck shut with dried soap (from last usage). In this case, remove the metering valve and carefully remove the ball and spring inside for a cleaning. After cleaning, re-install (spring goes first into injector body on pump with ball in metering valve). If this does not correct the problem replace complete chemical injector assembly.

Burner will not fire. Fuel is pumping into the burner but will not ignite. (Unit has a 12V burner system that relies on a good battery)

Here are some troubleshooting types to narrow this problem down onsite:
Test unit with good battery / use a jumper cable to attach a car battery (for test purposes only) If burner fires replace the battery
If still no fire / bypass the adjustable thermostat switch (round knob located at end plate of machine) by removing the end plate and jumping the connector pins - re-test. Leave the jumper on and go to next step
If still no fire / bypass the pressure switch by taking the cover off it and pushing the plunger in (simulating pressure activation) 
If still no fire test the electrodes for spark. Under the burner there is a square box with a hinge. Open this box . You will need to cover the photo electric eye with electrical tape so it does not see light. Wrap a jumper wire on each springs and position the free ends of the jumper wires within 0.25 inch of one another to simulate a burner electrode. With a good 12V battery (or jumper attached) inch you should get an arc. If you do not get an arc then you probably need a new Igniter.

No Heat - Burner not Firing

1. Tilt back burner hood and run pressure washer
2. Check the sight glass on the top of the burner for orange light (the burner is always on)
3. No spark - open the magneto door located in on the same end as the cart handle / mid section of the burner / held in place with two bolts (just in past the top of the diesel tank)
4. Turn the pressure washer over by hand and make sure magneto is turning.
5. Not turning - replace belt or check belt tensioner
6. Turning - ensure the spark electrodes (located on top of burner assembly) have a 1/4" gap. You can view this by removing the diesel nozzle line (located in the middle top of burner) -
7. Gap is okay - the problem must be with the ignition coil. Remove engine and pump as a unit and inspect that the coil has clearance from the flyweel. You may use a business card folded over to make sure there is gap between the coil and magneto flywheel. If the coil is hitting the flywheel - no spark will occur.
8. Still no spark- replace ignition coil

Fuel Shortage

Caused by plugged pilot circuit or bad or old fuel - you may be able to check this by partially moving the choke lever in around the middle position to see if the engine runs more consistent under load.

Dirt in the unloader valve

Do you still have an inlet screen on the garden hose connector? If your spray tips had dirt lodged into them it is very probable that your pressure regulator valve has some trapped dirt in it as well. You may want to try installing the Black soap tip in the end of the wand and do a repeated On / Off trigger for 15 - 30 seconds, this may help clear any debris that is trapped inside the unloader. You should also try adjusting the unloader knob (black) on pump. Back the knob off a turn or so and see if that helps the machine run more consistent - then turn it back in again. You may want to repeat this a few times while under load.