Graco 26D001, Operation And Parts

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Troubleshooting
3A8502A 17
Troubleshooting
1. Follow
Pressure Relief Procedure
, page 14,
before checking or repairing pump.
2. Check all possible problems and causes before
disassembling pump.
Daily Maintenance
Check the clamp nut (DN) on a daily basis and tighten if
necessary.
Problem Cause Solution
The pump fails to operate Damaged air valve Replace or service air valve (314).
Damaged pilot valve Replace pilot valves (313).
Inadequate air supply or restricted
lines.
Clean lines or increase the air supply.
See
Technical Specifications
, page
30.
Closed or clogged air valves Open or clear the valves.
Clogged fluid hose or valve Clear the hose or valve.
The pump operates, but the output is
low on both strokes
Clogged fluid hose or valve Clear the hose or valves.
Exhausted fluid supply Refill the fluid supply and reprime the
pump.
Worn or damaged valves or seals Service the valves or seals.
The pump operates, but the output is
low on the downstroke
Held open or worn intake valve Clear or service the valve.
Worn or damaged valves or seals Service the valves or seals.
The pump operates, but the output is
low on the upstroke
Held open or worn piston valve Clear or service the valve.
Worn or damaged valves or seals Service the valves or seals.
Erratic or accelerated operation Exhausted fluid supply Refill the fluid supply and reprime the
pump.
Pump slowly moves after fluid shutoff in
the downstroke
Clogged or dirty intake valve check ball Clean ball and seat.
Worn or damaged valves or seats
Install repair kit.
Pump moves slowly after fluid shutoff in
the upstroke
Clogged or dirty piston ball or seat Clean ball and seat.
Worn or damaged valves or seats Install repair kit.
Air continuously escapes around piston
rod
Damaged U-cups (307) Replace piston rod U-cup (307).
Air continuously escapes from muffler Damaged air valve plate (413) or cup
(414)
Replace or service air valve (314).
Air motor “bounces” at top of stroke Damaged bottom valve Replace bottom pilot valve (313).
Air motor “bounces” at bottom of stroke Damaged top valve Replace top pilot valve (313).
Icing inside motor Air motor operating at high pressure or
high cycle rate
Reduce pressure, cycle rate, or duty
cycle of motor. Reduce dew point of
compressed air in moisture-coalescing
filter.