Hach-Lange SD900 Basic User Manual - Manual (Page 16)

Calculate the pump cycle time
The pump must stay off for a minimum time period between sample cycles so that the power supply
does not overheat.
1. Calculate the total amount of time that the pump will run continuously during a sample cycle.
Include all stages: pre-purge, intake rinse, sample, sample retries and post-purge.
2. Find the minimum amount of time that the pump must stay off between sample cycles from
Figure 10 .
3. Make sure that the pacing or time interval in the sampler program lets the pump stay off between
sample cycles for the minimum amount of time.
Figure 10 Pump on and off times at 50 °C (122 ºF)
1 Time (in minutes) that the pump must stay off 3 Example: if the pump is on continuously for
5 minutes, the pump must stay off for 15 minutes.
2 Time (in minutes) that the pump is on continuously
Set the power to on
Push the power button to set the power to on or off. Make sure that the power supply (AC power or
battery power) is correctly installed.
User interface and navigation
The controller keypad is shown in Figure 11 . Use the MENU key to set up sampling programs,
configure the controller settings or complete the diagnostic tests. Use the arrows, ENTER and BACK
keys to scroll through the menu, make selections and enter values. Look for arrows on the bottom or
side of the display screen to know when more options are available.
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