Pressure washer: winterizing and frost protection

The danger: water freezing in the pump

This is THE winter failure of a pressure washer: residual water in the pump and pipes freezes, expands and cracks the pump body or seals. Repair often costs more than a new machine. Prevention takes 5 minutes.

Winterisation procedure

1. Cut off the water, unplug the inlet hose.
2. Run the machine for a few seconds without water supply, trigger pressed, to evacuate residual water (don't overdo it, the pump must not run dry for long).
3. Empty the lance, hoses and detergent tank.
4. Pump antifreeze (recommended) : draw in a little antifreeze solution specifically for pumps / winterisation fluid (or non-corrosive antifreeze) through the inlet, then let it run through. Protects seals and pistons.
5. Store in a dry, frost-free location if possible (heated garage, not an uninsulated shelter).

If pressure pulses or drops Often a non-return valve or air in the circuit — a diagnosis topic in itself, but start by checking the inlet filter and nozzle.

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