Haskel AAD-2 Instructions De Fonctionnement page 5

Pilot System
1. Remove hex o-ring sealed plugs (1 on each cap casting).
2. Remove spring and 27375 pilot stem valve (figure 3).
3. Inspect pilot stem and seat for foreign material. Replace stem if bent or damaged.
4. Replace stem if molded seat is damaged.
5. Reassemble in the reverse manner.
NOTE: Unless excessive leakage occurs, it is not advisable to replace the o-ring seal for the shank of the
stem. This requires disassembly of the air section. If replacement is required, care must be taken in
installing the Tru-Arc retainer concentrically as shown in figure 4. Use the 27375 pilot stem valve as a
seating tool. Place the rubber valve face against the retainer and tap the top of the valve lightly with a
light hammer to evenly bend the legs of the retainer.
Test procedure for pilot control valve:
After reassembly, if the pump will not cycle, the following test procedure will determine which of the pilot
valves is faulty.
1. Remove the 17658-2 1/8" pipe plug in upper end cap.
2. Install 0-160 psi pressure gauge.
3. Apply air pressure to the air drive inlet. Gauge will read zero pressure if lower pilot valve has not
been actuated. Gauge will read full drive pressure if upper pilot valve has not been actuated. Correct
pilot valve action will cause gauge to immediately rise or fall from zero to drive pressure. A slow
increase in gauge reading indicates leakage in lower pilot valve. A slow decrease in pressure
indicates upper valve or pilot tube end seals are faulty and repair is necessary. Check also for
external air leaks at plugs.
Piston and Barrel Sections
1. Remove tie rods.
2. Remove upper and lower caps.
3. Remove air barrel(s) and static seal o-rings.
4. Remove seals on air piston(s).
5. Remove one air piston to further remove rod from diaphragm.
6. Inspect rod seals.
7. Relubricate the inside of the air barrels with 50866 Haskel lubricant.
8. Replace air barrel end o-rings 568050 if pinched.
9. Install internal parts per drawing 27369.
10. Install air barrels and cap assemblies in reverse order.
Air Driven Air Amplifiers, AAD-2 & AAD-2-C • OM-9F
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