Hitachi 308996J important safety instructions Troubleshooting Chart, Problem Cause Solution

Troubleshooting Chart

WARNING

To reduce the risk of serious injury whenever you are instructed to relieve pressure, always follow the Pressure Relief Procedure on page 8.

1.Relieve the pressure.

2.Check all possible causes and problems before disassembling the pump.

PROBLEM			CAUSE	SOLUTION
The pump fails to oper-			Restricted air line or an inadequate air	Clear the line; increase the air supply.
ate.			supply; closed or clogged valves.	Check that the valves are open.
			Obstructed fluid hose or gun;	Open, clear*; use a hose with a larger ID.
			the fluid hose ID is too small.
			Fluid has dried on the displacement rod.	Clean the rod; always stop the pump at the bottom
				of its stroke;
				keep the wet-cup 1/3 filled with a compatible sol-
				vent.
			Dirty, worn, or damaged motor parts.	Clean or repair; see the separate motor manual
				308995.
The	pump	operates,	Restricted air line or an inadequate air	Clear the line; increase the air supply.
but the output is low on			supply; closed or clogged valves.	Check that the valves are open.
both strokes.
			Obstructed fluid hose or gun;	Open, clear*; use a hose with a larger ID.
			the fluid hose ID is too small.
			Worn u–cup seals in the displacement	Replace the u–cup seals.
			pump.
The	pump	operates,	Held open or worn intake valve.	Clear the valve; service.
but the output is low on
the downstroke.
The	pump	operates,	Held open or worn piston valve or u–cup	Clear the valve; replace the u–cup seals.
but the output is low on			seals.
the upstroke.
Erratic or accelerated			Exhausted fluid supply.	Refill the supply and prime the pump.
pump speed.
			Held open or worn piston valve or u–cup	Clear the valve; replace the u–cup seals.
			seals.
			Held open or worn intake valve.	Clear the valve; service.

*To determine if the fluid hose or gun is obstructed, follow the Pressure Relief Procedure on page 8. Discon- nect 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. If the pump starts when the air is turned on, the obstruction is in the fluid hose or gun.

NOTE: If you experience air motor icing, call your Graco distributor.

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