How to replace a pressure washer unloader valve
This step-by-step repair guide explains how to replace a pressure washer unloader valve.
When you let go of the trigger on the wand, the unloader valve opens to recirculate pressurized water to the pump, so the water won't overhead and damage the pump.
Common symptoms that indicate you need to replace the pressure washer unloader valve include:
The thermal release valve opens and sprays steam water from the pump. This happens when the unloader valve clogs or sticks shut.
Nozzle water pressure decreases quickly after you press the wand trigger. This symptom occurs when the unloader valve sticks open.
The engine stalls when you're not using the wand. When pressure builds up in the pump because the unloader valve isn't opening as it should, the engine can't continue to turn the pump shaft so the engine dies.
If the pressure washer unloader valve isn’t working, replace it using the manufacturer-approved gas pressure washer part. The unloader valve kit includes the O-ring and all parts needed for the repair.
Follow these steps to replace a Briggs & Stratton, Husqvarna, Troybilt, Snapper or Craftsman pressure washer unloader valve.
Instructions
- 01.
Disconnect the spark plug
Pull the spark plug wire off the spark plug on the pressure washer engine.
- 02.
Remove the unloader valve
Use an open-end wrench to turn the unloader valve counter-clockwise to remove.
PHOTO: Loosen the unloader valve.
PHOTO: Remove the unloader valve.
- 03.
Install the new unloader valve
Install the O-ring from the kit on the new unloader valve.
Lubricate the O-ring on the new unloader valve with silicone lubricant.
Thread the new unloader valve into the pump and tighten.
Tip: : If you have a torque wrench, tighten the new unloader valve 10-12 ft.-lbs.
PHOTO: Install the new unloader valve.
- 04.
Reconnect the spark plug
Reconnect the spark plug wire to the engine.
- 05.
Check pressure washer operation
Start the pressure washer and check for water leaks at the new unloader valve. Make sure that the new unloader valve works properly.
Symptoms for gas pressure washers
Choose a symptom to see related pressure washer repairs.
Main causes: faulty unloader valve, bad pressure regulator…
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Main causes: dirty air filter, stale fuel, clogged or dirty carburetor, bad unloader valve…
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Main causes: overfilling engine with oil, improper fuel/air mixture, choke system problems, dirty carburetor, engine nee…
Main causes: pump running for more than 5 minutes when the spray wand isn't being used, faulty pressure relief valve, ba…
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Main causes: damaged recoil starter, oil inside cylinder, locked up engine piston…
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