How to winterise your pressure washer and protect it from frost

After use, water can remain inside a pressure washer even when nothing is coming out of the lance. If that water freezes, it can damage the pump, filter housing, lines or heating coil. Prepare your equipment before the first frost, even if it is only spending the weekend in a vehicle or on a trailer.

Store the pressure washer in a dry, frost-free place. If there is a risk of frost while the equipment is parked, stored or transported, protect the water circuit as well. Before an extended period out of service, flush the circuit with clean water. Switch off the machine and release the pressure before disconnecting any fittings or removing the lance. On hot water models, switch off the heater first and let the machine cool as described in the operating manual. Keep the heater switched off while flushing with antifreeze.

Winterising a pressure washer using a separate container

On our standard pressure washers, feed the antifreeze solution through the water inlet and return it to the same container through the spray gun.

1. Prepare the antifreeze solution. Pour enough suitable antifreeze solution into a clean container. Follow the antifreeze manufacturer’s mixing instructions for the lowest temperature you expect.
2. Connect the hose. Attach a suitable hose to the water inlet and place the free end in the container. Keep the end submerged during flushing so the pump does not draw in air.
3. Circulate the solution. Start the pressure washer and direct the liquid back into the same container through the spray gun with the lance removed. Operate the gun several times so the solution reaches the safety components and the pressure gauge, if fitted.
4. Shut down the machine. Switch off the pressure washer and release the pressure as described in the operating manual. Drain any accessories that carry water and were not connected during flushing separately.

Winterising CLENA skids with a water tank

On our skids with a built-in water tank, add the antifreeze solution directly to the tank. The pump draws it from the tank and circulates it through the system, displacing any water left inside.

1. Drain the water tank. Drain any remaining water through the designated outlets. Residual water dilutes the antifreeze solution.
2. Add antifreeze solution to the water tank. Use a product suitable for the system. Follow the product instructions for the mixing ratio required at the lowest expected temperature. Add enough solution to keep the pump supplied throughout flushing.
3. Flush the system. Run the skid in the mode specified for this procedure. Pump the solution through the designated water circuits until it reaches each outlet. Depending on the configuration, include the heating coil, the hose on the reel, the return lines and any other outlets. Drain any lines that the solution does not reach, or protect them as described in the operating manual.
4. Collect the antifreeze and shut down the skid. Collect the discharged liquid as described in the operating manual, then shut down and depressurise the system. Before reusing the solution, check the level of frost protection it provides, as residual water may have diluted it.

Before the next use

Flush the antifreeze solution out with clean water as described in the operating manual, and collect it for reuse or proper disposal. If the machine will be exposed to frost again after use, repeat the winterising procedure.

The operating manual shows you which connections and water circuits to use. If you have questions about frost protection, contact CLENA Service.