520-069-000 8/00
Model EB½-A Type 2 Page 3
addressed by using a point of use air dryer (available from Warren Rupp) to supple-
ment a plant’s air drying equipment. This device will remove excess water from the
compressed air supply and alleviate the icing or freezing problem.
ESADS: Externally Serviceable Air Distribution System
Please refer to the exploded view drawing and parts list in the Service Manual
supplied with your pump. If you need replacement of additional copies, contact your
local Warren Rupp Distributor, or the Warren Rupp factory Literature Department at
the number shown below. To receive the correct manual, you must specify the
MODEL and TYPE information found on the name plate of the pump.
Models with suction/discharge less than 1"
The main air valve sleeve and spool set is located in the valve body mounted on
the pump with four hex head capscrews. The valve body assembly is removed from
the pump by removing these four hex head capscrews.
With the valve body assembly off the pump, access to the sleeve and spool set is
made by removing a retaining ring (each end) securing the end cap on the valve body
assembly. With the end caps removed, slide the spool back and forth in the sleeve.
The spool is closely sized to the sleeve and must move freely to allow for proper
pump operation. An accumulation of oil, dirt or other contaminants from the pump’s
air supply, or from a failed diaphragm, may prevent the spool from moving freely.
This can cause the spool to stick in a position that prevents the pump from operating.
If this is the case, the sleeve and spool set should be removed from the valve body for
cleaning and further inspection.
Remove the spool from the sleeve. Using an arbor press or bench vise (with an
improvised mandrel), press the sleeve from the valve body. Take care not to damage
the sleeve. At this point, inspect the o-rings on the sleeve for nicks, tears or abra-
sions. Damage of this sort could happen during assembly or servicing. A sheared or
cut o-ring can allow the pump’s compressed air supply to leak or bypass within the air
valve assembly, causing the pump to leak compressed air from the pump air exhaust
or not cycle properly. This is most noticeable at pump dead head or high discharge
pressure conditions. Replace any of these o-rings as required or set up a routine,
preventive maintenance schedule to do so on a regular basis. This practice should
include cleaning the spool and sleeve components with a safety solvent or equiva-
lent, inspecting for signs of wear or damage, and replacing worn components.
To re-install the sleeve and spool set, lightly lubricate the o-rings on the sleeve
with an o-ring assembly lubricant or lightweight oil (such as 10 wt. air line lubricant).
Press the set into the valve body easily, without shearing the o-rings. Re-install one
end cap, and retaining ring on the valve body. Using the arbor press or bench vise
that was used in disassembly, press the sleeve back into the valve body. Re-install
the spool, keeping the counter-bored end toward you, and install the spring, opposite
end cap, and retaining ring on the valve body. After inspecting and cleaning the
gasket surfaces in the valve body and intermediate, re-install the valve body on the
pump using new gaskets. Tighten the four hex head capscrews evenly and in an
alternating cross pattern, at 70 in./lbs. (7.9 Newton meters).
PILOT VALVE
The pilot valve spool (item 9C on main parts list) contains 6 o-rings (item 9D). This
spool moves through the sleeve (item 9B). Check condition of o-rings for cuts or
gouges before re-assembly. Apply a light coating of grease to the o-rings when
inserting into the sleeve. Insert spool in to sleeve from chamfered side. The o-ring on
the end should be installed after the spool is in place (install last). Make sure the
sleeve is locked into the intermediate bracket (item 16) with retainer ring (item 9E).
TROUBLESHOOTING
1. Pump will not cycle
A. Check to make sure the unit has enough pressure to operate and that the air inlet
valve is open.
B. Check the discharge line to insure that the discharge line is neither closed nor
blocked.
C. If the spool in the air distribution valve is not shifting, check the main spool. It must
slide freely.
D. Excessive air leakage in the pump can prevent cycling. This condition will be
evident. Air leakage into the discharge line indicates a ruptured diaphragm. Air
leakage from the exhaust port indicates leakage in the air distribution valve. See
Diaphragm and diaphragm plate.
Disassembling the pilot valve.
Pilot valve with o-rings.
DANGER
Before doing any maintenance on the
pump, be certain all pressure is
completely vented from the pump,
suction, discharge, piping, and all other
openings and connections. Be certain
the air supply is locked out or made non-
operational, so that it cannot be started
while work is being done on the pump.
Be certain that approved eye protection
and protective clothing are worn all
times in the vicinity of the pump. Failure
to follow these recommendations may
result in serious injury or death.
