Installation and Operation Manual
SA-07-11-87, Rev A
15
January 2019
Controlling the Pump During Startup
To ensure control of the pump during start up,
follow the start-up procedures for your desired
configuration.
Single Operation
Start the pump with the suction valve open while
throttling the discharge valve. This will ensure
that the pump will reach the design flow
operating point.
If the process fluid is near its vapor pressure,
open the supply vessel seal cavity vent so that
the pump can fill with liquid.
Parallel Operation
To prevent back-flow, place check valves in the
discharge piping of each pump.
Note: Sundyne recommends installing
separate bypass loops around each
pump for additional operational
flexibility.
1. Start the first unit as described in the
Single Operation instructions.
2. Start the second unit with the bypass
orifice/valve set to maintain the flow
above minimum flow.
3. Open the discharge valve on the second
unit so that the design flow of both units
is maintained.
Note: Do not operate the pumps at their peak
head capability.
Sundyne recommends that separate flow
controls be used on each pump to provide a
lower minimum flow range than is achieved by
pressure control.
Figure 6. Bypass System Example for Parallel Pump Operation
BYPASS
ORIFICES
FROM
SUPPLY
TO
SUPPLY
THROTTLE
CONTROL
VALVE
TRIM
VALVES
CHECK
VALVES
(
Or BYPASS
VALVES
)
