Troubleshooting - Graco DM-22 Manual

Troubleshooting

Troubleshooting
Problem
Pump fails to operate.
Pump operates, but output is low.
Erratic or accelerated pump.
* To determine if the fluid hose or gun is obstructed, follow the Pressure Relief Procedure on page 12. Disconnect
the fluid hose and place a container at the pump fluid outlet to catch any fluid. Turn on the air just enough to start
the pump (about 20-40 psi [0.14–0.28 MPa, 1.4–2.8 bar]). If the pump starts when the air is turned on, the
obstruction is in the fluid hose or dispensing device.
18
1. Follow the Pressure Relief Procedure, on page
2. Check all possible problems and causes before
Cause
Restricted line or inadequate air
supply; closed or clogged valves.
Obstructed fluid hose or gun/valve;
fluid hose ID is too small.
Fluid dried on displacement rod.
Dirty, worn, or damaged motor
parts.
Fluid is too heavy for pump priming
Intake valve is held open or worn or
seals are worn.
Exhausted fluid supply.
Fluid is too heavy for pump priming.
Intake valve is held open or worn or
seals are worn.
Priming piston is held open or worn.
Packings in displacement pump are
worn.
12, before checking or repairing the system.
disassembling system.
Clear; increase air supply. Ensure
that all valves are open.
Open and clear*; use a hose with a
larger ID.
Clean. Always stop pump at the bot-
tom of the stroke. Keep enclosed
wet cup 1/3 filled with a compatible
solvent.
Clean or repair; see separate motor
manual.
Use drain/purge valve; use a ram.
Clear valve; replace seals.
Refill and prime.
Use drain/purge valve.
Clear valve; replace seals.
Clear; service.
Replace packings.
Solution
3A7931B