Page 2 of 2 NM2304B-X-X (en)
PN 97999-750

GENERAL DESCRIPTION

The two-ball design provides for easy priming of the lower foot
valve. The double acting feature is standard in all ARO industrial
pumps. Material is delivered to the pump discharge outlet on both
the up and down stroke.
The motor is connected to the lower pump end with a spacer tube
and solvent cup. This allows for lubrication of the upper packing
gland and to prevent air motor contamination because of normal
wear and eventual leakage through the material packing gland.
WARNING
HAZARDOUS PRESSURE. Do not exceed maxi-
mum operating pressure of 600 p.s.i. (41.4 bar) at 150 p.s.i.
(10.3 bar) inlet air pressure.
Pump Ratio X = Maximum Pump
Inlet Pressure to Pump Motor Fluid Pressure
Pump ratio is an expression of the relationship between the pump motor area
and the lower pump end area. EXAMPLE: When 150 p.s.i. (10.3 bar) inlet pressure
is supplied to the motor of a 4:1 ratio pump, it will develop a maximum of 600
p.s.i. (41.4 bar)  uid pressure (at no  ow) - as the  uid control is opened, the  ow
rate will increase as the motor cycle rate increases to keep up with the demand.
WARNING
Refer to general information sheet for additional
safety precautions and important information.
NOTICE: Thermal expansion can occur when the  uid in the mate-
rial lines is exposed to elevated temperatures. Example: Material
lines located in a non-insulated roof area can warm due to sunlight.
Install a pressure relief valve in the pumping system.
Replacement warning label (pn 94520) is available upon re-
quest.

TROUBLE SHOOTING

Pump problems can occur in either the air motor section or the
lower pump end section. Use these basic guidelines to help deter-
mine which section is affected. Be sure to eliminate any possible
non-pump problems before suspecting pump malfunction.
Pump will not cycle.
No pressure to the motor. See motor manual.
Restricted return lines. Clean obstruction.
Damaged motor. Service the motor.
No material at the outlet (pump continually cycles).
Check the material supply, disconnect or shut o the air supply
and replenish the material, reconnect.
Material on one stroke only (fast downstroke).
The lower check may not be seating in the foot valve (see lower
pump disassembly). Remove the check from the foot valve,
clean and inspect the valve seat area. If the check or foot valve
are damaged, replace.
Material on one stroke only (fast upstroke).
The middle packings may be worn (see lower pump disassem-
bly). Replace the seals as necessary.
Material leakage out of the solvent cup or material appears on
the pump plunger rod.
Tighten the solvent cup until leakage discontinues. If this
procedure does not aid in stopping the leakage problem, the
upper packings may be worn (see lower pump disassembly).
Replace the seals as necessary.
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PUMP CONNECTION - UPPER / LOWER

NOTE: All threads are right hand.
Loosen (90606) lock nut and unscrew the entire pump from
the air motor. This will expose (94445) adapter (see  gure 2).
Unscrew (94445) adapter to remove pump assembly from the
air motor.
Remove the (Y15-21) cotter pin and (94048) clevis pin to re-
move (94445) adapter.
Pump Motor Piston Rod
PUMP CONNECTION DETAIL
Figure 2
Y15-21 Cotter Pin
Lower Pump Plunger
90606 Lock Nut (ref.)
94048 Clevis Pin
94445 Adapter

REASSEMBLY

Assemble (94445) adapter to the air motor rod, aligning the
through holes.
Assemble (94048) clevis pin through hole, securing adapter.
Assemble (Y15-21) cotter pin through the hole in the clevis
pin.
Apply Loctite® 242 to threads of (94445) adapter and screw
(94445) adapter into (90615-X) plunger.
Screw the lower pump assembly to the air motor.
Screw (90606) lock nut against the air motor base and tighten
to 50 - 60 ft. lbs (67.8 - 81.3 Nm).

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PUMP OPTION DESCRIPTION CHART

NM2304B- X 1 - X 1 X
Container Suitability
Packing Material
Spring Arrangement
Plunger Type
CONTAINER SUITABILITY PACKING MATERIAL
1 - Universal (stub) C - UHMW-PE (upper and lower)
4 - 55 Gallon W - Viton® (upper) / Virgin PTFE (lower)
3 - Virgin PTFE (upper and lower)
SPRING ARRANGEMENT PLUNGER TYPE
1 - Coil 1 - Standard (300 series stainless steel)
B - Ceramic
y Viton® is registered trademarks the DuPont Company y
y ARO® is a registered trademark of Ingersoll-Rand y
y Loctite® is a registered trademark of Henkel Loctite Corporation y