Graco GMAX 3400 - Fluid Pump Runs Constantly

Troubleshooting
3A6400A 31
Fluid Pump Runs Constantly
1. Perform Pressure Relief Procedure, page 13, turn
prime valve forward to SPRAY position, and turn
power switch OFF.
2. Remove control box cover.
Troubleshooting Procedure:
With a pressure gauge plumbed into the paint
hose, start the engine. Turn pump switch ON.
Does sprayer exceed maximum pressure?
Pump problem. See the proper fluid pump
manual for the sprayer for further
troubleshooting procedures.
Disconnect clutch wires from control board (see
diagram, page 36). Does the pump stop
running?
Mechanical problem in the clutch pinion
assembly (clutch may be close to the
Make sure clutch wires are plugged in (see
diagram, page 36). Do the clutch test points
read 10-18 DC volts?
Check for a short from the two clutch wires
to the frame. If shorted, repair or replace
faulty wire.
Unplug transducer from control board.
Bad transducer.
Replace and test with a new one.
Replace the control board.
YES
NO
YES
YES
YES
NO
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NO