To maintain constant pressure and prevent frequent startup, a small-capacity pressure tank is needed in the sys-
tem (refer to the minimum capacity of pressure tank table below). The VARIOspeed
®
3R Duplex control panel may
use a pressure tank of a larger capacity than listed on the table below.
Minimum Capacity of Pressure Tank
Flow Rate (GPM)
Tank Size
(Total Capacity)
Less than 12.0
4 Gallons
More than 12.0
8 Gallons
More than 50.0
14 Gallons
Pre-Charge Pressure
1. Initial charge pressure should be set at 70% of the system pressure (Set pressure).
2. To maintain the optimum pressure control, check the air pressure in the tank regularly.
Set Pressure (PSI)
Initial Charging
Pressure (PSI)
50 (default)
35
55
39
60
42
65
46
A Pressure Relief Valve Must be Installed.
A pressure relief valve
MUST
be installed as close as possible to the pump discharge and plumbed to a drain able
to handle the full flow of the pump in the event of a malfunction.
WARNING!
Failure to use a pressure relief valve could result in burst pipes and flooding if a system failure should occur.
Pressure Tank/Pressure Relief Valve/Low Pressure
10 VARIO
speed
®
3R Duplex User Manual
