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For example: if the Deviation HI value is set for 10 degrees Fahrenheit and the
SP temperature is set for 50 degrees Fahrenheit, the alarm will trigger at 60
degrees Fahrenheit. If the SP temperature value is changed to 55 degrees
Fahrenheit, the deviation HI will not trigger the alarm until it reaches 65 degrees
Fahrenheit. If the Control Action is set for COOL and the alarm condition exists
when the RUN key is pressed, the alarm will not be activated. The PV tempera-
ture must first fall below the alarm setpoint to enable the high alarm. This allows
for normal system startup without activating the alarm.
Select DEVIATION - HI by pressing the MENU key. The following screen will
appear (refer to Figure 25). Set the Deviation HI temperatures by using the
arrow keys. Once the alarm value is set, press the MENU key to advance to
one of the other alarm variables.
Deviation HILO
1. Deviation HILO allows the operator to set the alarm to actuate below and
above the SP temperature. Refer to Figure 26.
DEVIATION ALARM
HI XXXXX °F
FIGURE 25. DEVIATION HI SETTINGS SCREEN
ALARM MODE
DEVIATION HILO
FIGURE 26. DEVIATION HILO SCREEN
For example: if the SP temperature is set at 50 degrees Fahrenheit and
the operator sets the Deviation HILO value at 10 degrees Fahrenheit, the
alarm will sound below 40 degrees Fahrenheit and above 60 degrees
Fahrenheit. To allow for normal system startup, the alarm may not be
activated under certain conditions. Refer to the DEVIATION HI and DE-
VIATION LO sections for additional information on alarm activation.
