Bennett 111103, Operation, Service & Parts Manual

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Bennett T140 Operation, Service, & Parts Manual Troubleshooting
18
VAPOR LOCK
Vapor lock is a problem that results from ambient temperatures, vapor pressure of the product, and the installation. It is not a characteristic of a
pump.
REASONS FOR VAPOR LO CK

The Atmospheric Pressure, of 14.7 PSI (Seal Level) presses on the liquid in the tank
as shown in Figure 18 .

Vapor Pressure (the amount of pressure required to keep the product in a liquid
form at 60

F) of today’s product is approximately 10 PSI. See Figure 19 .

The difference between Atmospheric Pressure and Vapor Pressure is known as the
Working Pressure . The Working Pressure is all that the pump can create without
the product turning to vapor. To figure the Working Pressure take Atmospheric
Pressure minus the Vapor Pressure (i.e. Calculation: Atmospheric Pressure – Vapor
Pressure = Working Pressure) Refer to
Figure 20 .
Example: 14.7 - 10.0 = 4.7 PSI
Figure 18
Figure 19
Figure 20
10 PSI required to keep product
in liquid form
60°F
_
14.7 PSI Atmospheric Pressure
4.7 PSI Working Pressure
10.0 PSI Vapor Pressure at 60°F
_____
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