Thrush PC2G - Manual (Page 4)

between the check valve and the pump, or the priming can be done with a bucket and funnel. It
is important to completely fill the suction pipe and pump casing with liquid.
When the pump is started, the vacuum created by pumping the priming fluid combined with
atmospheric pressure in the liquid well forces liquid into the suction piping, thus opening the valve
and keeping it open until the pump is shut down. When the pump is shut down, the liquid being
pumped reverses its flow causing the valve to close. The liquid is now trapped in the suction
piping and pump casing, thus maintaining a prime on the pump.
VACUUM PRIMING
Vacuum priming consists of removing air from the pump casing and suction piping and drawing
liquid into them by means of a vacuum-creating device. The types of vacuum equipment range
from a simple hand pump to a complex central priming system. The specific priming
requirements will govern what type of vacuum primer to use.
STARTING THE PUMP
The discharge gate valve should be partially closed when the pump is started in order to avoid
possible water hammer and initial power draw. As soon as the pump is up to operating speed,
the discharge gate valve should be opened to the desired position. The motor should turn
clockwise when viewed from the motor end and counter-clockwise when viewed from the casing
end.
Figure 2
MAINTENANCE
It is doubtful that a THRUSH pump will ever require complete disassembly. Generally, only
certain components need be disassembled to accomplish inspection or repair.
DISASSEMBLY
Since the THRUSH PC/E-300 & PC2G is of back pull out design, it is unnecessary to disconnect
the piping or casing for service. All service and maintenance can be performed by disconnecting
the coupling and removing the power frame assembly from the casing.
1. Close suction and discharge valves.
2. Break electrical connections to prevent drive unit from being energized during
disassembly.
3. Unscrew two of the pipe plugs (29) from top and bottom of the casing (28).