Insufficient water supply is the most common cause.
- Turn the garden hose on fully.
- Check the entire hose for kinks, leaks, or blockage. Remove any.
- Your garden hose diameter may be too small. Replace it with a 1” (25 mm) or 5/8” (16 mm) hose.
- A pressure tip is not installed on the wand assembly. Add a spray tip to the end of the wand. The machine needs backpressure to build power.
If pressure still varies high and low, the pump is sucking air. Turn the water and machine “OFF”, then purge the pump by squeezing the trigger on the spray wand. Do this a few times to clear air from the system, then restart.
Ensure your faucet is turned on fully and there are no kinks or leaks in the hose before starting.