rhdf2dl1sm-rev0413
Model RHDF2 Page 15
Read these instructions
completely, before
installation and start-up.
It is the responsibility of
the purchaser to retain
this manual for reference. Failure to
comply with the recommendations stated
in this manual will damage the pump, and
void factory warranty.
IMPORTANT
FLAP VALVE SERVICING
Valve inspection requires removal of 3/8" hex nuts and elbows. When the top suction elbows are
removed, the valve and seat are connected as an assembly. When the bottom discharge elbows are
removed, the valve and seat stay with the outer chamber. Visual inspection and cleaning is possible. If
parts are to be replaced, remove the self-locking nuts and all parts are accessible.
DIAPHRAGM SERVICING
Diaphragms can be inspected or the diaphragm assembly removed without removing the suction and
discharge flanges. Remove (8) nuts around the chamber flange, and the housing assembly will pull
off. Flap valves can be inspected for proper seating at this point as well as the diaphragm. Use care to
keep foreign matter from behind the diaphragm. The opposite diaphragm may be inspected by the same
procedure. If either diaphragm has to be replaced, follow closely these steps: Pull the outer diameter
of one diaphragm off the (8) capscrews. NOTE: One side only! On the free diaphragm assembly, use
a 3/8" allen wrench to turn the assembly (diaphragm, plates and screw) loose from the shaft. Once the
assembly has turned, it will turn out by hand by use of the diaphragm. Now the opposite diaphragm
assembly and the drive shaft will pull free from the capscrews and pump intermediate assembly. The
interior components consisting of sleeve bearings, rod seals, and pilot valve actuator bushings are now
accessible for service if required. Hold the shaft in a clamping device making sure to protect surface of
shaft so as not to scratch or mar it in any way. The diaphragm assembly will turn loose. To disassemble
the components, turn a 1/4"-20 capscrew by hand into the tapped hole in the inner plate. This keeps the
plate from turning while the socket head capscrew is removed. To do this, place assembly in a vise so
the two protruding ends of screws are loose in the vise jaws (about 3/4" apart). Turn the center screw
loose from the back plate and the assembly will come apart.
“airVantage caution” – if product is observed on the air side of the diaphragm, refer to the “air-
Vantage Servicing” section of the service manual.
REASSEMBLY
All procedures for reassembling the pump are the reverse of the previous
instructions with further instructions as shown:
The diaphragm assemblies are to be installed with the natural bulge outward or toward the head
of the center screw. Make sure both plates are installed with outer radii against the diaphragm. After
all components are in position in a vise and hand tight, set a torque wrench for 480 inch pounds (40 ft.
pounds) (54.23 Newton
meters) or, 600 inch pounds (50 ft. pounds) (67.79 Newton meters) for Santoprene, using a (3/8") allen
head socket. After each diaphragm sub assembly has been
completed, thread one assembly into the shaft (held near the middle in a vise having soft jaws to protect
the finish) making sure the stainless steel washer is in place on the capscrew.
Make sure 1/4"-20 mounting screw has been removed and that the bumper (Item #19 on drawing) is
in place in the shaft.
Install this sub assembly into the pump and secure by placing the outer chamber housing and
capscrews on the end with the diaphragm. This will hold the assembly in place while the opposite side is
installed. Make sure the last diaphragm assembly is torqued to 30 ft. lbs. (40.67 Newton meters) before
placing the outer diaphragm over the capscrews. If the holes in the diaphragm flange do not line up with
the holes in the chamber flange, turn the diaphragm assembly in the direction of tightening to align the
holes so that the capscrews can be inserted. This final torquing of the last diaphragm assembly will lock
the two diaphragm assemblies together. Place
remaining outer chamber on the open end and tighten down the securing nuts
gradually and evenly on both sides.
Caution should be used while reassembling Flap valves. The valves are designed for some preload
over the retainer hinge pad. This is done to insure proper face contact with the seat. After all parts are
in place, tighten the lock nuts down on the assembly to the point where visual inspection shows that
seat and valve face mate without gap. This is important for dry prime. However, after priming action has
started, valves will function due to differential pressure without concern or trouble.
PILOT VALVE
The pilot valve assembly is accessed by removing the main air distribution valve body from the
pump and lifting the pilot valve body out of the intermediate housing.
Most problems with the pilot valve can be corrected by replacing the o-rings. Always grease the
spool prior to inserting it into the sleeve. If the sleeve is removed from the body, reinsertion must be
at the chamfered side. Grease the o-rings to slide the sleeve into the valve body. Securely insert the
retaining ring around the sleeve. When reinserting the pilot valve, push both plungers (located inside the
intermediate bracket) out of the path of the pilot valve spool ends to avoid damage.
PILOT VALVE ACTUATOR
Bushings for the pilot valve actuators are threaded into the intermediate bracket from the outside.
The plunger may be removed for inspection or replacement. First remove the air distribution valve body
and the pilot valve body from the pump. The plungers can be located by looking into the intermediate. It
may be necessary to use a fine piece of wire to pull them out. The bushing can be turned out through the
inner chamber by removing the outer chamber assembly. Replace the bushings if pins
have bent.
