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18
PI Operation Manual
5.1 PRIMING
The most common method used for warming a pump, or maintaining a standby pump in a warm
condition, is the use of a warming line and orifice, thus circulating the hot pumpage through the
idle pump.
It is recommended that the pump be warmed at the rate of 100 °F (55 °C) rise
per hour for normal warming, or 268 °F (149 °C) rise per hour for emergency warming.
It is recommended that the idle pump temperature be maintained within 36 °F
(20 °C) of the system operating temperature.
Circulation can be easily accomplished by guiding a small amount of flow from the discharge
side of the system beyond the check valve via a multiple breakdown orifice into the bottom of the
pump case. The hot liquid will then pass through the case and out the suction and return to some
low pressure point in the system. In many cases, the pump drain line is used for the warming
connection.
Note: Many variations are possible and one that is compatible with the customer’s particular
installation should be considered.
5.2 STARTUP
Every time before the pump is started up the safety devices must be mounted and fastened.
In order to avoid risks of injury or damage, all pump units must be equipped with emergency-
stop devices.
For operation of electrical drives, control systems and their cable routes, the safety
instructions issued by their manufacturers must be observed.
5. SECTION FIVE - OPERATION
