Why has my pressure washer lost pressure?
Loss of pressure is the most common complaint and has several possible causes, in order of likelihood: (1) worn or enlarged nozzle orifice - check and replace the nozzle first; (2) unloader valve not holding correct bypass pressure - inspect and adjust; (3) worn pump packing - look for water dripping from the pump wet end; (4) dirty or failed inlet/outlet check valves - inspect and clean or replace; (5) insufficient water supply causing cavitation - verify inlet pressure and flow rate. Start with the nozzle. It is inexpensive, easy to replace, and responsible for a large percentage of pressure loss complaints.
Why is my pump pulsating or surging?
Pump pulsation or surging (pressure cycling up and down rapidly) typically indicates: (1) insufficient water supply - the pump is starving for water, which causes cavitation; check your supply flow rate and pressure; (2) a partially blocked inlet strainer - clean the strainer; (3) a failing inlet check valve - air is entering the pump on the suction stroke; (4) worn packing causing the plunger to lose efficiency on the pressure stroke. Cavitation (water starvation) is the most common cause - ensure your water supply can meet the machine's GPM demand.
Why won't my burner ignite?
Common causes of burner ignition failure: (1) no fuel - check fuel level and fuel shutoff valve; (2) clogged fuel nozzle - replace the fuel nozzle; (3) clogged fuel filter - replace the filter; (4) failed fuel pump - check fuel pump pressure output; (5) electrodes out of adjustment or eroded - inspect and adjust electrode gap, replace if tips are eroded; (6) failed ignition transformer - check transformer output; (7) flow switch not closing circuit - check flow switch operation and water supply. Work through these systematically rather than guessing.
Why is the burner igniting but then shutting off?
If the burner lights but shuts off shortly after: (1) flow switch is tripping due to insufficient water flow through the coil - check water supply and flow switch; (2) high temperature limit switch is tripping due to overheating - check water flow, thermostat operation; (3) flame sensor or stack switch is not detecting the flame properly - inspect and clean; (4) the thermostat is set too low and is shutting off the burner immediately - check thermostat setting; (5) the coil has heavy scale restricting flow, causing the flow switch to trip - descale the coil.
Why is water leaking from my pump?
Water leaking from the pump's wet side (between the plunger/piston area and the crankcase) indicates worn packing - this is normal wear and packing should be replaced. Water leaking from fittings or connections indicates a loose fitting, damaged O-ring, or cracked fitting. Oil mixed with water in the crankcase (milky oil) indicates the oil seal has failed, allowing pump water to enter the crankcase - this requires pump disassembly and oil seal replacement. Address packing and seal leaks promptly to prevent further pump damage.
Why is my machine not building any pressure at all?
If the machine starts but builds no pressure: (1) the nozzle may be completely blocked - inspect and clear; (2) the unloader valve may be stuck in bypass - inspect and free or replace; (3) both inlet and outlet check valves may be stuck open - inspect check valves; (4) the pump may have lost prime due to air lock - shut down, restore water supply, and allow water to flow through before restarting; (5) the pump may have a broken or seized internal component. If all simple causes have been ruled out, the pump likely needs professional service.
Why is my machine producing less hot water than usual?
Reduced hot water output on a hot water unit typically indicates: (1) the thermostat is set lower than expected - check the setting; (2) the coil has significant scale buildup reducing heat transfer efficiency - descale the coil; (3) the fuel nozzle is worn or partially clogged, reducing burner output - replace the fuel nozzle; (4) the air band is out of adjustment, causing inefficient combustion - have the burner tuned; (5) the burner is cycling off too frequently due to a thermostat or flow switch issue. A stack thermometer can help diagnose combustion efficiency.
My machine is running but producing excessive noise - what is wrong?
Excessive noise can indicate: (1) cavitation - a rapid chattering or crackling sound caused by insufficient water supply; check inlet pressure and flow; (2) worn or loose pump components - a knocking or rattling sound; (3) a failing bearing in the motor or engine - a grinding or rumbling sound; (4) a loose belt on belt-drive machines - a squealing or slapping sound; (5) debris in the pump or nozzle causing erratic flow. Cavitation is the most common cause of sudden noise increase and can rapidly damage the pump - address it immediately by ensuring adequate water supply.
What is pump cavitation and how do I prevent it?
Cavitation occurs when the pump cannot draw enough water to fill its cylinders on each intake stroke, causing water vapor bubbles to form and collapse violently inside the pump. The collapsing bubbles create the characteristic chattering noise and cause pitting damage to pump internals - valves, plungers, and pump housings. Prevent cavitation by ensuring your water supply delivers adequate pressure (minimum 20–30 PSI) and flow rate (at least equal to your machine's GPM rating) at the pump inlet. A float tank can buffer inconsistent supply and prevent cavitation.