While you may want to stick with some soapy water and a sponge to give your new vehicle the tender, loving cleaning it deserves, you’ll need some real power to properly clean your driveway, deck, or home siding. That’s where an electric or gas-powered pressure washer really earns its keep. But what do you do if your pressure washer is leaking water? To answer this question, you should know a little about how a pressure washer operates, when you can expect water to be discharged, and when it should not.
How the pressure washer operates
Unlike air, water cannot be compressed. When pressure is applied to it, the water will push out in every direction equally. Pressure washers use this principal to create a high pressure stream of water that can be controlled by the operator.
A pressure washer consists of two main components: a power source and a water pump. For electric pressure washers, the power source is an electric motor whereas the power source on most gas-powered washers will be a 4-cycle engine. The pump may be an axial pump or a tri-plex pump. Although these two pumps look different, both use three plungers or pistons that operate in a similar manner to a piston in an engine. As each plunger or piston travels upward, it draws water from an attached garden hose through an input check valve. As the plunger or piston travels downward, the water is forced through an output check valve. The water then flows through an unloader and output pipe on the pump, and, finally, through a hose to the spray gun.
When the spray gun trigger is depressed, the pressurized water will exit through the trigger handle assembly itself or through a separate spray wand and nozzle. When the trigger is released, the high-pressure water stream should stop. The unloader will then detect the increase in pressure and a spring-loaded valve will open a passage in the pump so the water can circulate back to the inlet pipe. This feature allows the engine to run while the pressure washer is not in use.
Why is my pressure washer releasing hot water when not in use?
Over time, the water circulating inside the pump gets hot. If the operator leaves the pressure washer running for an extended period of time without activating the trigger, a thermal release valve will open and discharge the heated water so cooler water can enter the pump. This is an expected function of the pressure washer and is not indicative of a malfunction.
Common pressure washer parts to fix water leaks
If the pressure washer is consistently leaking water at the bottom, from the high-pressure hose, or the trigger handle, these are the parts that may need to be replaced:
- Thermal release valve – While the thermal release valve is expected to discharge water periodically, if it is continually emitting water, then the valve is likely defective and will need to be replaced.
- Pump – If the compressed air is not purged from the pump before operation, it can damage the check valve, plungers, and unloader which can cause the pump to malfunction and leak water.
- Check valve, plungers, O-rings – While some pumps are sold as a complete assembly, other pumps will allow you to replace the check valve, plungers, and O-rings separately to repair the pump.
- High-pressure hose – Be sure to only use a dedicated high-pressure hose to connect the inlet pipe to the spray gun. The hose’s pressure rating should be higher than the pump, which can typically be 1,300 psi to 1,700 psi for electric models and 2,000 psi to 3,200 psi for gas-powered models. A hose with a pressure rating lower than the pump can become damaged and leak.
- Trigger handle / hose O-ring – If water is leaking near the trigger handle or high-pressure hose, you may need to replace the O-ring that sits between the spray wand and trigger handle, or the ones on either end of the hose.
Find the right pressure washer parts with Repair Clinic
Repair Clinic carries the parts that match all the top brand pressure washers, including Briggs and Stratton, Generac, Craftsman, Honda, Kärcher, Kohler, Troy-bilt, and more. To see a full list of compatible parts, enter the full model number of your pressure washer, or the pressure washer’s engine, in the Repair Clinic search bar. You can use the part category and part title filter to narrow that list down to the exact part you want such as a thermal release valve, pump, or O-ring kit.