Haskel 8 Serie Instructions De Fonctionnement Et D'entretien page 9

NOTE: The following procedures reflect removal of the pilot valve from both the control valve end cap and
flow fitting end cap of drive section. Use applicable paragraphs depending on which pilot valve is to be
inspected and/or repaired.
5.3.1 Disconnect all plumbing lines necessary to allow separation of cycling valve assembly from position
on end cap.
5.3.2 Using suitable wrench to hold long nut, remove bolt, lockwasher and flat washer located on topside
of flow fitting.
5.3.3 Remove two cap screws, lockwashers and flat washers located on underside of cycling valve
assembly (or flow fitting). Using care to prevent damage or loss of small parts, lift cycling valve assembly
(or flow fitting) from end cap. Remove spring, o-ring and pilot valve stem.
5.3.4 Remove flow tube and pilot tube. Inspect o-rings on ends of both tubes and replace any if damaged,
worn or swollen. Relubricate with 50866 lubricant.
5.3.5 Inspect pilot valves for damage. Replace valve if stem is bent or scratched.
5.3.6 A molded seat valve is used under the flow fitting, while a replaceable o-ring seat valve (with orifice)
is used under the cycling valve assembly. lnspect replaceable o-ring and replace if damaged, worn or
swollen. Inspect molded seat on opposite pilot valve. If damaged, replace pilot valve. The molded seat
pilot valve under the flow fitting uses the shorter of the two springs.
NOTE: Unless excessive leakage occurs, it is not
advisable to replace the inside seal on the stem of
either pilot valve as this requires disassembly of the
air drive cylinder. If replacement is required, care
must be taken in installing the Tru-Arc retaining ring
concentrically as shown in (Fig. 7.) Using the pilot
stem valve with the molded seat as a seating and
centering tool, put the retaining ring, retainer and
seal on the stem so that the molded rubber face of
the valve is against the retaining ring. Insert in seal
cavity. Tap the top of the pilot valve lightly with a
small hammer to evenly bend the legs of the
retaining ring.
5.3.7 Apply Haskel 50866 Lubricant to pilot valve
parts and reassemble in the reverse manner.
5.4 Pilot System Testing
If the air drive will not cycle, the following test procedure will determine which of the pilot valves is faulty:
5.4.1 Remove gauge port pipe plug (p/n 17568-2) located in the cycling valve body, next to the retaining
screw.
5.4.2 Install pressure gauge and test per 6.3.1 – 6.3.3
5.4.3 Check also for correct spring length (Ref. Paragraph 5.3.6) and external air leaks at gauge plug, or
ends of pilot tube.
5.5 Air Drive Section
Disassemble air drive cylinder section and piston in the following manner (while referring to your detailed
assembly drawing):
5.5.1 Disconnect all plumbing lines on double ended models to allow pump sections to be moved left or
right when drive section is separated.
5.5.2 Remove bolt, lock washer and flat washer (hold long nut to prevent unscrewing) located on topside
of flow fitting.
8" Drive Liquid Pumps • OM-LP-800F
Figure 7. Centering and installing seal
retaining ring using pilot step as tool
9