Why won’t the motor start? Why does the motor hum?

  • Make sure the unit is plugged to a grounded electric receptacle.


  • Make sure the power switch is turned on.


  • Make sure to use the proper extension cord: A 25-foot cord should be at least 14 gauge; a 26 – 50-foot cord should be at least 12 gauge; a 51 – 100-foot cord should be at least 10 gauge. Use of an extension cord more than 100' in length is not recommended.


  • If you turned the sprayer power switch to “Off” and did not put the prime/spray knob in the “Prime” position, or if the sprayer became unplugged, the sprayer is still under pressure and will not start. Turn the prime/spray knob to the “Prime” position and pull the gun trigger. This will release all pressure in the system. If the motor won’t start after you have done this, the thermal overload must reset itself. Allow the sprayer to sit in the “Off” position for approximately 20 minutes.


  • If the motor shuts off while in use, the thermal overload protection circuit was activated. Low amp draw (improper size extension cord, low power input from the source, etc.) is one thing that can activate the thermal overload protection. Turn the sprayer off, let it sit for approximately 20 minutes, and correct the source of the electrical problem. High ambient temperature can also activate the thermal overload protection circuit. Move the unit out of direct sunlight and/or cover the unit with a damp towel to absorb some of the heat.