These selections provide the logic to control a Preheat coil. During startup, Preheat controls the CD-T to the OALT-SP (Low Limit Setpoint).
The selection options for Coils (Preheat) are:
Preheat
Preheat Lockout from Outdoor Air
Staged Heating
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Device Rotation
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No Flow Lockout: This option loads the flow switch for staged heating. The current loss of airflow sequencer provides the proper behavior.
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High Temperature Lockout: This option turns off staged heating when a High Temperature alarm occurs.
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Number of Stages
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One Stage
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Two Stages
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Three Stages
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Four Stages
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Five Stages
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Six Stages
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Seven Stages
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Eight Stages
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Hot Water or Steam
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Proportional Output
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Two Valves
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Face and Bypass Damper
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Proportional Actuator
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Incremental Actuator
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Incremental Output
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Face and Bypass Damper
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Proportional Actuator
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Incremental Actuator
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Two Position Output
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Face and Bypass Damper
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Proportional Actuator
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Incremental Actuator
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Entering Water Temperature
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Leaving Water Temperature
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Coil Pump
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Pressure/Flow Boost
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Low Temperature Circulation
- Both Pressure/Flow & Low Temp Circulation: This option combines the existing two sequences to start the pump either when the valve command exceeds zero or when the outdoor air temperature drops below the setpoint.
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Dual Pumps: This option adds a second coil pump to operate in a duty/standby configuration.
- Rotate to Balance Runtime: When you select this option with Dual Pumps, the application automatically shifts the lead to the pump with the lowest operating hours.
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Pump Status
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Loss of Status Strategy
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Automatic Restart
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Manual Restart
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Unit Reset Switch (BI)
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Alarm Management
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Lockout Switch
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Motor Overload Tripped
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Automatic Restart
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Manual Restart
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Unit Reset Switch (BI)
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Blocking Protection: This option provides monitoring of the command to a motor (typically a pump). If the command is off for an extended period of time (for example, 7 days), the motor starts for a short time (for example, 30 seconds). This feature prevents blocking (that is, it prevents the motor from seizing up).
- Shutdown AHU when pump is in Alarm: For applications with Preheat pumps, this option prevents the unit from starting if there is a fault in the preheat pump during cold weather.
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Face and Bypass Switchover
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Based on Outdoor Air Temperature
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Based on Network Input
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Shutdown Strategy
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Off
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Remain in Control
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Protect Coil Based on Outdoor Air Temperature
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Low OA Temperature - Leaving Water Control: This option adjusts the state table entries to force the application to control for Low OA temperature while in shutdown.
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User Defined Position
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Loss of Airflow Strategy
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Off
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Remain in Control
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Protect Coil Based on Outdoor Air Temperature
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Low OA Temperature - Leaving Water Control: This option turns on the coil pump if the outdoor air temperature is lower than the setpoint and the unit is off. The preheat valve is modulated to control the leaving water temperature.
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User Defined Position
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Unreliable Sensor Operation
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Off
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Hold
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Protect Coil Based on Outdoor Air Temperature
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User Defined Position
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The option for Two Proportional Valves is intended for two sequenced steam valves. This option does not support including Face & Bypass Damper or Circulation Pump controls.
The Face and Bypass Switchover option is applicable only when either a Proportional or Incremental valve actuator is selected with Face and Bypass Damper. This option specifies how to determine when the valve should be in control (with the Damper at full face) and when the damper should be in control (with the Valve fully open).
The Remain in Control Shutdown Strategy is available only when a proportional valve is selected (with either proportional or incremental actuator).
The Loss of Airflow Strategy options are available only when the Automatic Restart option for the Supply Fan Status Loss of Airflow Strategy is selected.