Warnings - Daikin MicroTech III Operation Manuals

Warnings

Over Economizing
A warning alarm indicating the unit is economizing when it
should not be will be generated whenever the outdoor air
dampers are stuck open while operating in the Econo or
Cooling operating state . The dampers are considered stuck
open when either of the following abnormal situations occurs:
• The damper command value is less than the calibrated
damper end switch closed value continuously for 180
seconds yet the outside air damper end switch input
remains open .
• The damper end switch input does not change from
closed to open with 30 seconds of the damper command
value dropping (and remaining) below the calibrated
damper end switch open value (less the calibrated
maximum switch differential) .
The over economizing warning will also be generated if
the Econo Status is Enabled when the OAT is greater than
the Max OAT Limit setting (default 75F) . Exception: This
case is ignored when the economizer enable decision is
being controlled by a network input or when the economizer
changeover method (EconChgovr) is set for OAT/RAT dry bulb
comparison (OAT/RAT) .
The alarm will automatically clear when the conditions causing
the alarm are no longer present .
NOTE: The damper end switch open (PosSwOpen%),
Minimum switch differential (MinSwDiff), damper end
switch closed (PosSwClose%) and maximum switch
differential (MaxSwDiff) values are determined during
the OAD damper end switch calibration process .
Under Economizing
A warning alarm indicating the unit is not economizing when it
should be will be generated whenever the outdoor air dampers
are stuck closed while operating in the Econo or Cooling state .
The dampers are considered stuck closed when either of the
following abnormal situations occurs:
• The damper command value is greater than the
calibrated damper end switch open value continuously for
180 seconds yet the outside air damper end switch input
remains open .
• The damper end switch input does not change from
closed to open with 30 seconds of the damper command
value rising above the calibrated damper end switch
closed value (plus the calibrated minimum switch
differential)
The under economizing alarm will also be generated if the
Econo Status is not Enabled when the OAT is less than
the Min OAT Limit setting (default 70F) . Exception: This
case is ignored when the economizer enable decision is
being controlled by a network input or when the economizer
changeover method (EconChgovr) is set for OAT/RAT dry bulb
comparison (OAT/RAT) .
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The under economizing alarm will also be generated when the
OAT sensor is unreliable or the RAT sensor is unreliable while
the OAT is below the Min OAT Limit setting (default 70F) and
the economizer changeover method (EconChgovr) is set for
OAT/RAT dry bulb comparison (OAT/RAT) .
The alarm will automatically clear when the conditions causing
the alarm are no longer present .
NOTE: The damper end switch open (PosSwOpen%),
Minimum switch differential (MinSwDiff), damper end
switch closed (PosSwClose%) and maximum switch
differential (MaxSwDiff) values are determined during
the OAD damper end switch calibration process .
Excess OA
A warning alarm indicating the unit is delivering excessive
outdoor air will be generated whenever the outdoor air
dampers are stuck open . The outdoor dampers are considered
stuck open when either of the following abnormal situations
occurs:
• The damper command value is less than the calibrated
damper end switch closed value continuously for 180
seconds yet the outside air damper end switch input
remains open .
• The damper end switch input does not change from
closed to open with 30 seconds of the damper command
value dropping (and remaining) below the calibrated
damper end switch open value (less the calibrated
maximum switch differential) .
The excess outdoor air warning will also be generated while
operating in the Econo or Cooling state when the Econo
Status is Enabled and the OAT is greater than the Max OAT
Limit setting (default 75F) . Exception: This case is ignored
when the economizer enable decision is being controlled by
a network input or when the economizer changeover method
(EconChgovr) is set for OAT/RAT dry bulb comparison (OAT/
RAT) .
The alarm will automatically clear when the conditions causing
the alarm are no longer present .
NOTE: The damper end switch open (PosSwOpen%),
Minimum switch differential (MinSwDiff), damper end
switch closed (PosSwClose%) and maximum switch
differential (MaxSwDiff) values are determined during
the OAD damper end switch calibration process .
The alarm will automatically clear when the conditions causing
the alarm are no longer valid .
79 OM 920-6 • MICROTECH UNIT CONTROLLER
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