Excessive Pressure Build Up - Graco Magnum L10 Repair Manual

Advanced Troubleshooting
Specific Problem
Motor runs and pump cycles, but
pressure does not build up.
Specific Problem
Prime/Spray Valve actuates
automatically, relieving pressure
through drain tube.
26
Cause
Intake valve or outlet valve is not
seating properly.
Pump packings are worn or
damaged.

Excessive Pressure Build Up

Cause
Pressure control switch has
pinched wires or switch is worn.
Water or paint entered pressure
control switch or shorted control
board.
Control board failed.
Solution
Remove and clean inlet valves and outlet valves.
Replace if necessary. See List of Kits, page 30.
Check for leaking around pump.
L30+: Replace pump packings. See List of Kits,
page 30.
M5, L10, M3+, M5+, L10+: Replace complete pump.
See List of Kits, page 30.
Solution
Replace pressure control switch using Pressure
Control Switch Kit, page 28.
Use Pressure Control Switch Kit, to replace
switch. See List of Kits, page 30.
See Control Board Diagnostics, page 29. Replace
damaged control board using Control Board Kit.
See List of Kits, page 30.
332642C