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Adjusting the High Pressure Bypass Setting
Chiller with positive displacement or turbine pumps incorporate an automatic safety to maintain outlet pressure
below a valve-regulated pressure. This valve is adjustable and is located inside the Chiller housing.
WARNING: There are exposed fan blades inside the Chiller housing. Exercise extreme care when accessing
or adjusting any interior components.
WARNING: Hazardous voltages are present.
To access the high-pressure bypass valve, remove the two screws at the upper left and right corners of the
Chiller’s rear panel, slide the top panel back about 2-3 inches, and lift off. The regulator valve is located in the left
rear corner of the unit.
The high-pressure bypass is adjusted as follows:
1. Set the low flow rate alarm value to zero (see Setting Operational Parameters, Minimum Flow Rate). This
will prevent the unit from activating the flow alarm while you are adjusting the maximum pressure setting.
2. Completely block the Chiller’s outlet flow. This should cause the outlet pressure to rise.
3. Set the Pressure/Flow Rate display to read either PSI or kPa.
4. Rotate the handle on the pressure valve until the desired maximum pressure setting is shown on the
Pressure/Flow Rate display.
5. Reset the flow alarm value to the previous setting.
6. Return the Pressure/Flow Rate display to the previous setting.
7. Replace the top panel of the Chiller, being sure to secure the bayonet-style prongs on the front of the panel
in the openings at the front of the unit. Reinsert the two screws that secure the top panel to the rear panel of
the unit.
Enabling / Disabling the Local Lockout
This feature is used to prevent unauthorized or accidental changes to set point and other operational values.
When enabled, the values for the following functions can be displayed, but not changed:
• Temperature unit
• Temperature set point
• Ambient tracking offset
• Pressure / flow rate units
To enable the local lockout, press and hold the Select/Set Knob until LLO is displayed (approximately 5 seconds).
Once enabled, LLO will appear momentarily when the Select/Set Knob is pressed to display the set point.
To disable the local lockout, press and hold the Select/Set knob until CAn appears momentarily as local lockout
status changes from enabled (LLO) to disabled (approximately 5 seconds).
CAUTION: The Local Lockout feature does not prevent set point changes entered via the RS232 interface.
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