Pressure Washer Setup & Surface Cleaning
Attach nozzles correctly, set pressure for different surfaces, and avoid damage to wood, concrete, and siding.
Table of Contents
Assembly and Connection
Unpack the pressure washer and verify all components are present: powerhead, high-pressure hose, spray gun, wand, nozzles, and detergent siphon tube if included. Connect the high-pressure hose to both the pump outlet and the spray gun, ensuring the fittings are hand-tight plus a quarter turn with pliers — overtightening damages O-rings.
Connect the garden hose to the water inlet with a filter screen installed to prevent debris from entering the pump. Turn on the water supply and squeeze the spray trigger until a steady stream flows — this purges air from the system and prevents dry-running the pump, which destroys seals within seconds.
Never run a pressure washer without water flowing through it. Even 5 seconds of dry operation can destroy the pump seals and require expensive replacement.
Nozzle Selection by Surface
Start every job with the widest nozzle that will get the job done. The white 40-degree tip is gentle enough for windows, soft wood, and painted siding. The green 25-degree tip is the general-purpose choice for concrete, brick, and composite decking. The yellow 15-degree tip handles heavy grime on driveways and patios. The red 0-degree tip is rarely needed for cleaning and primarily used for stripping or cutting — use it with extreme caution.
For vertical surfaces like siding, work from the bottom up to prevent streaking. Keep the nozzle 12-18 inches from the surface and maintain constant motion — holding the spray in one spot etches or strips the material. Test an inconspicuous corner first, especially on aged wood or painted surfaces.
Detergent and Chemical Use
STIHL pressure washers with detergent tanks or siphon tubes can apply cleaning chemicals at low pressure through the black soap nozzle. Apply detergent from the bottom up and let it dwell for 5-10 minutes without drying. Re-wet if the solution begins to evaporate before rinsing.
Use only pressure-washer-safe detergents. Bleach, acids, and solvents can damage pump seals, harm plants, and discolor surfaces. For mold and mildew, a solution of oxygen bleach (sodium percarbonate) is effective and safer than chlorine bleach. Rinse thoroughly with clean water using the green or white nozzle after chemical application.
Cover delicate plants with plastic sheeting before pressure washing nearby surfaces. Even mild detergents and high-pressure spray can damage foliage.
Post-Use Maintenance
After completing work, shut off the engine and squeeze the trigger to release residual pressure. Disconnect the high-pressure hose and drain it completely — trapped water freezes and cracks the hose in winter. Flush the detergent system with clean water to prevent chemical residue from corroding internal components.
Remove and inspect nozzles for debris. Clear blocked orifices with a thin wire, then flush with water. Store nozzles in a protective case to prevent damage. Coil the high-pressure hose without kinks and hang it rather than leaving it on the ground where it can be crushed or punctured. Cover the pressure washer or store it in a shed to protect from weather and UV degradation.
