Programming instructions

Programming Power Block settings
43
Temperature alarms and alarm biasing
Select Ventilation gives you the ability to set low and high temperature alarms.
 There is a low temperature alarm condition when low alarm is enabled and the temperature is
lower than the low set point
 There is a high temperature alarm condition when high alarm is enabled and the temperature is
higher than the high set point.
Alarm biasing gives you the ability to add a buffer for the high alarm to help prevent the alarm from
sounding on very hot days.
Alarm biasing requires the ability to monitor outdoor temperatures. Monitoring
outdoor temperatures requires an outdoor temperature probe. For more
information, read the Monitoring outdoor temperatures section of the
OMNI Select
user manual.
How alarm biasing works for PBx Power Blocks
For PBx Power Blocks, you set the bias offset and the high alarm maximum. Select Ventilation adds the
bias offset to the outdoor temperature to create a new setting called the biased high alarm. The biased
high alarm becomes the new temperature limit, up until the high alarm maximum. When the
ambient temperature is higher than the biased high alarm, there is an alarm condition.
In the following example, the high alarm temperature is 75°F, the bias offset is 5°F, and the high alarm
maximum is 85 °F.
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Temperature (ºF)
Time of day (hh)
Outdoor High alarm Biased high alarm Maximum high alarm Ambient
Alarm condition past the maximum
Biasing starts Biasing ends
Alarm condition past the bias