
8-2
Valco Cincinnati, Inc.
Section 8 - Troubleshooting
MS013 - DD-1 Pump Manual (built after 9/06)
Problem
Possible Cause
Possible Solution
3. Pump runs without
flow.
3a. Suction leakage
3b. Blocked suction line
3c. One or more check valves not
seating
3d. Diaphragm failure
3e. Pump is sucking in air
3a. Test and repair suction components.
3b. Check and clean suction strainer if
used. Check installation.
3c. Shut pump down and service check
valves.
3d. Replace diaphragm if necessary.
3e. Check all fittings. Use pipe sealant to
seal fittings.
4. Pump
speeds
up
noticeably without
a proportionate
increase in flow as
air pressure is
increased.
4a. The pump may be beginning to
cavitate due to excessive
restriction in suction lines or
insufficient suction-line
diameter.
4a. If suction line checks out for size and
tightness, cavitation can be stopped by
turning the regulator knob
counterclockwise to reduce air
pressure..