How to Install a Pressure Washer Check Valve Kit

 

file

Pressure washer check valves let enough water flow through the pump and manifold to pressurize the water at to the nozzle. If the check valves are damaged, the pump won’t build pressure. Air in the inlet water supply can damage the check valves, as can chemical residue left in the pump. Replace damaged check valves by installing a manufacturer-approved check valve kit, following the steps in this repair guide.

Repair difficulty:
     
Time required:

Less than 120 min.

Parts Required

  • Check valve kit

For manuals, repair guides, and specific part recommendations, enter your model number.

Tools Required

  • Allen head bit set and ratchet
  • Sheet metal screw (for removing the check valves)
  • Thread-locking adhesive
  • Mechanic’s pick
  • Hose clamp for chemical injection tube
  • Torque wrench (optional)
  • Work gloves

Before you begin

Wear work gloves to protect your hands.

Allow the engine and pump to cool before servicing.

 

Instructions

 Warning: Undertaking repairs to appliances can be hazardous. Use the proper tools and safety equipment noted in the guide and follow all instructions. Do not proceed until you are confident that you understand all of the steps and are capable of completing the repair. Some repairs should only be performed by a qualified technician.

Step 1: Disconnect the spark plug

Disconnect the spark plug wire from the spark plug.

Step 2: Prepare the pressure washer for service

Remove the gas cap.

To prevent fuel from leaking from the tank, place a plastic bag over the mouth of the tank and then reinstall the gas cap. 

Remove the inlet water hose and the outlet nozzle hose connection from the pump.

 

Step 3: Remove the caps from the manifold check valves

Use a wrench to remove the caps from the check valves on the side of the pump manifold.

 Tip: Be prepared for water to spill from the manifold when you remove the check valve caps.

Step 4: Remove the manifold check valves

Insert a sheet metal screw into the plastic body of the check valve and screw it down so it grips the check valve body, and then pull the screw and check valve body out of the pump.

Use a mechanic’s pick to remove any residue left by the valve body or seals out of the pump body.

Repeat the process to remove all the check valves.

 

Step 5: Install the new manifold check valves

Insert the new check valves into the body of the pump. 

Press the check valves down so that they seat properly.

 

Step 6: Reinstall the manifold check valve caps

Place a small amount of thread-locking adhesive on the check valve cap threads.  

Reinstall the check valve caps and tighten them securely.  

 

 Tip: Ensure that the O-rings are in place and seat properly when reinstalling the check valve caps.

Step 7: Remove the pump manifold

If fluid is in the chemical injection tube, clamp the tube off.

Pull the chemical injection tube off the chemical injection inlet valve on the pump manifold.

Tip the pressure washer to access the bottom of the pump.

Remove the 3 Allen-head screws that secure the manifold to the pump. 

Pull the manifold off of the pump.

Set the manifold down on a stable work surface.

 

 Tip: Be prepared for some water to spill out of the manifold when removed.

Step 8: Remove the check valves

Remove the water seals from the top of the check valves.

Insert a sheet metal screw into the plastic body of the check valve and screw it down so that it grips the check valve body.

Pull the screw and check valve body out of the pump.

Use a mechanic’s pick to remove any residue left by the valve body or seals out of the pump body.

Repeat the process to remove all of the check valves.

Step 9: Install the new check valves

Insert the new check valves into the body of the pump. 

Press the check valves down so that they seat properly.

Install the water seals at the top of the check valves.

Step 10: Reinstall the pump manifold

Position the manifold on the pump and replace the mounting screws.

Tilt the pressure washer upright.

Reinstall the chemical injection tube on the chemical injection inlet valve on the manifold. Remove the clamp from the chemical injection tube.

 Tip: If you have a torque wrench, torque the screws to 18 to 20 ft. lbs. of torque.

Step 11: Restore the pressure washer to its operating condition

Remove the gas cap, the plastic bag from the mouth of the gas tank and reinstall the gas cap.

Reattach the spark plug wire.

Step 12: Test the pressure washer operation

Run the pressure washer and check for leaks. 

Check for proper pressure at the nozzle.