Instruction Manual

1. WHAT CAUSES THE DDP-20 TO START?
The DDP-20 has the built-in pressure switch and internal ow switch.
Each of these can turn the pump on depending on water consumption.
The pump will start when:
- The pressure is BELOW the pressure switch activation point. OR
- The ow rate is greater than 0.7 GPM.
2. WHAT CAUSES THE DDP-20 TO STOP?
The ow switch is designed to automatically stop the DDP-20 when ow drops to below 0.7 GPM.
The DDP-20 is programmed to stop after 8 seconds. In addition, the DDP-20 will be turned o in the event of
dry-run or over temperature alarm.
3. WHAT IS THE PURPOSE OF THE BUILT-IN PRESSURE TANK?
The pressure tank comes from the factory pressurized at approximately 20 psi (with the pump pressure at
zero). It is designed to minimize motor startup due to small ow demand or minor leak of the pipeline.
4. HOW IS THE DRY-RUN CONDITION DETERMINED AND THE PROTECTION
PROVIDED?
The dry-run is dened when the motor is running AND the ow rate is less than 0.3 GPM AND when pressure
is less than the pressure switch setting.
The protection is provided:
• When the pump is run dry 2 minutes, it will automatically shut o for 10 minutes and then attempts to
restart.
• When all 3 attempts are failed, the pump will rest for 1 hour and then attempts to restart.
• This protection mode will be repeated until the water supply is back to normal.
In case the pump is cycling (on-and-o repeatedly) due to small ow (less than 0.3GPM), air pocket in the
system, air loss in the pressure tank or leak in the pipeline, the protection is provided:
• The pump will run for 8 seconds and stop for about 3 seconds.
• When the cycling mode repeats for 15 times consecutively, the pump will rest for 1 hour.
• Then it will start over the protection mode until the problem is corrected.
Note: The pump can be reset anytime by removing the power plug.
5. WHAT IS THE MAXIMUM INLET PRESSURE ALLOWED IN THE DDP-20?
• The maximum internal system pressure allowed for DDP-20 is 120 psi.
• The maximum inlet pressure when added to the DDP-20 pressure must not exceed 120 psi.
For example with a 40 psi inlet pressure supplied to the pump, internal system pressures can reach
approximately 107 psi (67 + 40 psi). Additionally, if inlet pressures exceed the built-in pressure switch
activation point (20 psi factory default), the pressure switch will be unable to function, and the ability to turn
the DDP-20 on at low ow rates will be lost. In this situation, only the ow switch will be able to turn the DDP-
20 on at ow rates above 0.7 gpm.
Built in the U.S.A.
9
FREQUENTLY ASKED QUESTIONS
FREQUENTLY ASKED QUESTIONS