Finish Thompson UC (S/N 125040 and lower) - Manual (Page 9)

9
figure 6
RECOMMENDED
NOT
RECOMMENDED
figure 7
5. The suction line should not have any high spots. This can create air pockets. The suction piping
should be level or slope slightly upward to the pump (see figure 6)
6. The NPSH available to the pump must be greater than the NPSH required. Filters, strainers, and any other fittings in
the suction line will lower the NPSH available and should be calculated into the application.
7. A check valve and a control valve (if used) or isolation valve should be installed on the discharge line. The control
valve is used for regulating system flow. An isolation valve is used to make the pump accessible for maintenance.
It is recommended that the control or isolation valve be closed prior to stopping or starting the pump. The check
valve is installed to protect the pump against water hammer damage. These recommendations are particularly
important when the static discharge head is high.
8. It is advisable to install a flush system in the piping to allow the pump to be flushed before the pump is removed
from service.
9. When connecting piping to the pump suction
and discharge flanges, if lock washers are
used, install under the head of the bolt.
See figure 7.
Piping
1. The pump should be installed as near to the suction source as possible.
2. It is recommended that pipes are supported as close as possible to the pump and all flanges line up. This will
minimize any pipe strain.
3. The suction side of the pump should be as straight and short as possible to minimize pipe friction or a length at
least ten times the inlet diameter should follow any elbows.
4. The suction or inlet line should be at least as large as the suction inlet port or one pipe size larger so that it does not
affect the NPSHa. Do not reduce the suction line size.