Model MSA3 Page 2 msa3dl7sm-REV0317
AIR VALVE LUBRICATION
The Sandpiper pump’s pilot valve and main air valve assemblies are designed
to operate WITHOUT lubrication. This is the preferred mode of operation.
There may be instances of personal preference, or poor quality air supplies when
lubrication of the compressed air supply is required. The pump air system will
operate with properly lubricated compressed air supplies. Proper lubrication of
the compressed air supply would entail the use of an air line lubricator (available
from Warren Rupp) set to deliver one drop of 10 weight, non-detergent oil for every
20 SCFM of air the pump consumed at its point of operation. Consult the pump’s
published Performance Curve to determine this.
It is important to remember to inspect the sleeve and spool set routinely. It
should move back and forth freely. This is most important when the air supply is
lubricated. If a lubricator is used, oil accumulation will, over time, collect any debris
from the compressed air. This can prevent the pump from operating properly.
Water in the compressed air supply can create problems such as icing or
freezing of the exhaust air causing the pump to cycle erratically, or stop operating.
This can be addressed by using a point of use air dryer (available from Warren
Rupp) to supplement a plant’s air drying equipment. This device will remove excess
water from the compressed air supply and alleviate the icing or freezing problem.
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 or 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 1" suction/discharge or larger and METAL center sections
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 four hex head capscrews (each end) on the end caps of 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 abrasions. 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 equivalent, 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, gasket and bumper on the valve body. Using the arbor press or
bench vise that was used in disassembly, press the sleeve back into the valve
body. You may have to clean the surfaces of the valve body where the end caps
mount. Material may remain from the old gasket. Old material not cleaned from this
area may cause air leakage after reassembly. Take care that the bumper stays in
place allowing the sleeve to press in all the way. Reinstall the spool, the opposite
end cap, gasket and bumper on the valve body. After inspecting and cleaning the
gasket surfaces on the valve body and intermediate, reinstall the valve body on
the pump using new gaskets. Tighten the four hex head capscrews evenly and in
