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to the active space temperature setpoint. If there is no RAT
Sensor, the control will shut down all outputs. If the detected
sensor failure is a short circuit, the error can be declared only if
the short persists for several minutes, in order to distinguish a
sensor failure from a short caused by somebody pushing on
Unoccupied Override button.
VAV operation: If the space temperature sensor fails, the
control will continue normal function, only SAT reset from space
temperature will be disabled.
BUILDING PRESSURE SENSOR
If this sensor fails, the Power Exhaust control will default to
operate as a two position Power Exhaust. The Power Exhaust
Fan will be controlled as a fixed speed, ON/OFF Power exhaust
fan, controlled from position of the Economizer damper. If the
unit is equipped with a Modulating Exhaust Air Damper, this
damper will be closed.
DUCT STATIC PRESSURE SENSOR
If this sensor fails, all outputs are turned off and the unit is shut
down.
IAQ SENSOR
If the IAQ sensor fails, Demand Ventilation mode is de-activated.
SYSTEM ERRORS
HEATING SAT FAILURE
In Heating mode and all stages of heating energized, the SAT
must drive above the Supply Air Alarm Setpoint for Heating
within ten minutes or this SAT failure error will be activated. The
error will be written to the Error History Buffer. In networked
application, the error flag will be readable by the network.
COOLING SAT FAILURE
In Cooling mode and all stages of compression are energized, the
SAT must drive below the Supply Air Alarm Setpoint for Cooling
within ten minutes or this SAT failure error will be activated. The
error will be written to the Error History Buffer. In networked
application, the error flag will be readable by the network.
Subject to change without notice. Printed in U.S.A.
Copyright © 2008 by Johnson Controls, Inc. All rights reserved.
SUPPLY FAN FAILURE
The conditions under which this failure is declared, and the
follow-up actions of the control when this error occurs are
described in a paragraph on Air Proving Switch Operation
earlier in this document. The error will be written to the Error
History Buffer. In networked application, the error flag will be
readable by the network.
COMPRESSOR SAFETY CHAIN TRIP
The conditions under which this failure is declared, and the
follow-up actions of the control when this error occurs are
described in a paragraph on Compressor Status Monitoring
earlier in this document. The error will be written to the Error
History Buffer. In networked application, the error flag will be
readable by the network.
DIRTY FILTER ALARM
The conditions under which this failure is declared, and the
follow-up actions of the control when this error occurs are
described in a paragraph on Dirty Filter Switch (DFS) option
earlier in this document. The error will be written to the Error
History Buffer. In networked application, the error flag will be
readable by the network.
HIGH DUCT STATIC ALARM
The conditions under which this failure is declared, and the
follow-up actions of the control when this error occurs are
described in a paragraph on Duct Static High Limit Setpoint
option earlier in this document. The error will be written to the
Error History Buffer. In networked application, the error flag will
be readable by the network.
HOT WATER COIL FREEZE ALARM
The conditions under which this failure is declared, and the
follow-up actions of the control when this error occurs are
described in a paragraph on FSI (Hot Water Freeze Protection)
option earlier in this document. The error will be written to the
Error History Buffer. In networked application, the error flag will
be readable by the network.
Johnson Controls Unitary Products
5005 York Drive
Norman, OK 73069
351579-YTS-B-0608
Supersedes: 351579-YTS-A-0208
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