SANDPIPER MP05D - Manual (Page 17)

520-168 thru 171-000 3/03 Models MP05D, MP08D, MP12D and MP14D Design Level 1 Page 5
suction is indicated by a high vacuum reading when a vacuum gauge is installed in
the suction line.
C. Check valves may not be seating properly. To check, remove the suction line
and cover the suction port with your hand. If the unit does not pull a good suction
(vacuum), the check valves should be inspected for proper seating.
D. Static suction lift may be too high. Priming can be improved by elevating the
suction and discharge lines higher than the check valves and pouring liquid into the
unit through the suction inlet. When priming at high suction lifts or with long suction
lines operate the pump at maximum cycle rate.
3. Low performance
A. Capacity is reduced as the discharge pressure increases, as indicated on the
performance curve. Performance capability varies with available inlet air supply.
Check air pressure at the pump inlet when the pump is operating to make certain
that adequate air supply is maintained. Low flow rate as discharge pressure in-
creases can also be a sign of too little or no driver liquid in the spill containment
chamber.
B. Check the vacuum at the pump suction. Capacity is reduced as vacuum
increases. Reduced flow rate due to starved suction will be evident when the cycle
rate can be varied without change in capacity. This condition will be more prevalent
when pumping viscous liquids. When pumping thick, heavy materials the suction
line must be kept as large in diameter and as short as possible, to keep suction loss
minimal.
C. Low flow rate and slow, cycling rate indicate restricted flow through the dis-
charge line. Low flow rate and fast cycling rate indicate restriction in the suction line
or air leakage into suction.
D. Unstable cycling indicates improper check valve seating on one chamber.
This condition is confirmed when unstable cycling repeats consistently on alternate
exhausts. Cycling that is not consistently unstable may indicate partial exhaust
restriction due to freezing and thawing of exhaust air.
CHECK VALVE SERVICING:
Need for inspection or service is usually indicated by poor priming, unstable
cycling, reduced performance or the pump’s cycling but not pumping.
DIAPHRAGM SERVICING:
1. Driver Diaphragms:
Drain the driver diaphragm chamber by removing the boss plug on the underside
of the driver chamber and/or pipe plug at the leak detection tee. Remove bolts
securing the two manifolds to the chambers. Remove eight bolts securing the dia-
phragm chamber. This permits inspection of the pumping diaphragm and the driver
diaphragm. Loosen the plate which secures the diaphragm and plate to the rod by
keeping the diaphragm engaged with the inner diaphragm chamber by inserting two
or three capscrews through the bolt holes so that the diaphragm cannot rotate when
loosening. The diaphragm plates, diaphragm and bumper will now come off the
assembly. Repeat all actions if the other diaphragm needs to be inspected or re-
placed.
NOTE: See “Filling of Spill Containment Chamber with Liquid” for the correct
procedure to recharge the pump for operation.
Procedures for reassembling the diaphragms are the reverse of the above. The
driver diaphragms must be installed with their natural bulge to the outside, toward the
outer diaphragm plate. Install the inner plate with the flat face against the diaphragm.
After all components are in position in a vise and hand, tight, tighten with a wrench.
Initial Torque requirements
MP05D ......................................... no torque required
MP08D ......................................... 40 ft. lbs. (54.23 Newton meters)
MP12D ......................................... 40 ft. lbs. (54.23 Newton meters)
MP14D ......................................... 50 ft. lbs. (67.79 Newton meters)
After both diaphragm assemblies have been assembled, thread one assembly
into the shaft (hold the shaft near the middle in a vise with soft jaws, to protect the
CAUTION
Do not use a wrench on the diaphragm
rod. Flaws on the surface may damage
bearings and seals.