Insert a charged, functional battery into the sprayer.
If you don't have a spare functional battery, press the indicator button on your battery. If no LED lights appear or if the lights are red, the battery must be replaced.
A voltmeter can be used to check the battery in question. Turn your voltmeter to 200V DC. Hold the positive electrode on the positive battery terminal and hold the negative electrode to the negative battery terminal. It should read close to 18V. If there is there is a low or zero reading, the battery must be replaced.
STEP 2: Check the pressure dial/rocker switch.
FOR DUAL-PRESSURE UNITS: unscrew the cover plate and set aside. Unscrew the strain relief fitting. Using pliers, disconnect the spade fitting from the power switch and move to the neighboring extra set of wire contacts. Test the sprayer.
FOR VARIABLE-PRESSURE UNITS: If the dial rotates continuously, without a stopping point, replace the dial.
STEP 3: Check the microswitch.
Locate the microswitch housing (shaped like the letter "P") at the bottom of the pump. Remove the top and bottom screw from the housing to reveal the microswitch.
Using pliers, remove the connection that sits the furthest away from the pump. DO NOT PULL ON THE WIRE; squeezing the tab while pulling on the connector will release the pin and it should come off with ease.
Insert a battery into the sprayer and turn the power on. Bypass the microswitch by touching the disconnected terminal to the terminal that is still connected to the pump. Note: you may need to pull down the see-through rubber insulators to ensure metal-to-metal connection.
If this test causes the pump to turn on, you have a defective microswitch. If this test does not activate the pump and you know your battery to be functional, you likely need a replacement circuit board.
Tools Required: Phillips-Head Screwdriver
STEP 1: Check for leaks from the gun.
STEP 2: Check for leaks from the hose and pump.
Unscrew the cover plate and remove. With water in the sprayer, start spraying and look for leaks.
If the sprayer is leaking where the hose connects to the pump, tighten the hose clamp.
If you notice a leaking from the pump diaphragm, replace the diaphragm/pump.
STEP 1: For VARIABLE-PRESSURE sprayers
Check if the pressure dial is rotating continuously with no stopping point. If so, the dial and circuit board must be replaced.
If the dial is functioning normally, replace the circuit board only.