SANDPIPER ST40 - Manual (Page 8)

st15dl4sm-rev0614 Models ST1½, ST40 Page 6
For installations involving the use of rigid piping, short flexible sections of hose are
recommended between the pump and piping. This will reduce piping strains and
vibration.
FILLING THE DRIVER CHAMBERS WITH LIQUID
THE DRIVER CHAMBERS WILL BE FILLED WITH DISTILLED WATER AT THE
FACTORY. IF THE INNER CHAMBER IS CAST IRON, THE UNIT IS FILLED WITH
ETHYLENE GLYCOL.
If you prefer to substitute another liquid, to prevent system contamination consult the
factory first to determine compatibility of the substitute with pump construction.
Follow the steps listed below to replace the liquid in the pump after disassembly or
liquid loss:
1. Disconnect air supply from pump before starting any work. Remove the fill and drain
plugs (¼ NPT) (.0635 cm) from the driver chambers. After the chambers are completely
drained of all liquid, replace the drain plugs and tighten them securely. NOTE: Use thread
sealant on plug threads.
2. Remove the two large (1 NPT) (2.54 cm) pipe plugs (one on each side) located in
the rear of the innermost air chambers.
3. Determine which side of the pump is on the discharge stroke and which side is on
the suction stroke by checking the positions of the diaphragm assemblies. The cast inner
diaphragm plate closest to the pump intermediate housing, or centerline, is the chamber
in the suction stroke position. The opposite chamber, with cast inner diaphragm plate
away from unit centerline, is in the discharge stroke position. NOTE: The diaphragm
assemblies (cast inner diaphragm plates) are visible through the two tapped holes in
the inner chambers from which the two large pipe plugs were removed.
4. Fill the driver chamber on the suction side of the pump with 1.20 liters or 40 to 41
fluid oz. by volume accuracy to 1 oz. (28.41 ml) with the driver liquid chosen for use.
The driver liquid chambers must be filled with the correct amount of the driver liquid as
too little or too much liquid can cause premature diaphragm failure and erratic pumping.
5. After filling, the liquid will not come all the way to the top of the filling hole. Use a
screwdriver or similar tool to apply leverage on the inner diaphragm plate (diaphragm
assembly) forcing the driver diaphragm on the side you have just filled partially through
its discharge stroke until the liquid level in the chamber you are filling comes to the top of
the fill hole. This displaces any air in the chamber. CAUTION: Do not pry on or damage
the elastomer diaphragm while performing this step of the filling instructions.
6. Re-plug the fill hole and tighten securely. NOTE: Use thread sealant on plug threads
and tighten only until snug.
7. Using a screwdriver or similar tool apply leverage on the inner diaphragm plate
(diaphragm assembly), on the side just filled, forcing the pump to “shift” or reverse
diaphragm positions.
8. Follow steps (4) thru (6) to fill the opposite driver chamber.
9. Re-install the two large pipe plugs in the rear of the pump inner air chambers.
NOTE: Use thread sealant on plug threads.
Revised Filling Procedure:
For pumps with air valve 031-098-000
Insert the safety clip (210-008-330, item 61) on one side of the main air valve body
and cycle the pump at 5 to 10 psi. As you face the pump, the side with the pin should
be the first driver fluid reservoir to be filled. The driver diaphragm will be on a suction
stroke. Pour the correct amount of liquid into the reservoir. The fluid level will not come
completely to the top. Loosely install the pipe plug, with pipe dope, PTFE tape or o-ring
(depending on pump model) placed on the threads. Release all air pressure to the pump
and remove the safety clip. The diaphragm will relax and will come to center. Watch the
loose pipe plug closely as air escapes and the driver fluid level rises. Insert the safety
clip on the opposite side and add a small amount of air pressure. When you see liquid
weeping out between the loose pipe plug and fill hole, tighten the pipe plug. Repeat the
procedure for the unfilled chamber.
If you have a problem getting the driver fluid to come to the top, a blunt instrument
can be inserted into the chamber port of the pump and pressure can manually be applied
to the pumping diaphragm to cause the liquid to come to the top. Do this carefully.
A needle valve for precision stroking control is recommended at the air inlet for this
procedure. Please be aware that air left in the chambers will result in faulty operation of
the pump and will cause premature pumping diaphragm failure.