Contemporary Controls BASstat BAST-221C-BW2 User Manual page 17

Heat or Ventilation@Heat when the thermostat is in Heat mode (automatic), and Cool or
Ventilation@Cool when the thermostat is in Cool mode (automatic).
Dual Stage Heat and Cool with Manual Changeover – In this control type the thermostat will
wait for a command from user or BACnet supervisor to switch between Cool and Heat modes.
The user will be presented with a choice of Heat or Ventilation@Heat when the thermostat is in
Heat mode, and Cool or Ventilation@Cool when the thermostat is in Cool mode. The user can
choose to switch between Cool and Heat modes using the MODE button.
BACnet controlled – In this control scheme, the built-in thermostat algorithm can be bypassed,
and the thermostat can be controlled over the BACnet network with commands from the
supervisor device. The logic executing in the supervisor (such as Niagara or Sedona logic) can
control the thermostat over the BACnet network. To put the thermostat in BACnet network
control mode, use the Lock [AV18] object bit 9: Control DOs by thermostat algorithm "0"
(default) or BACnet supervisor "1" (add decimal=512).
Cool Only (nullified/disabled in firmware), and Heat Only (nullified/disabled in firmware) control
types are listed in the BACnet object and Engineering Menu object but are not available for
use.
Fan Output in Heat Mode
By default, the BASstat thermostat will not provide Fan output signal when in Heat Mode since
most HVAC comfort systems such as RTU systems provide their own fan control signal based
on a delay after a call for heating. This can be configured from Engineering Menu item (F-Ht)
or BACnet object [BV15] Fan Output For Heating. The default value is "0". To enable fan
control signal output for heating coming from the BASstat, set this value to "1".
Algorithm
• A PID adaptive control algorithm is applied to minimize overshoot, in addition to
proportional band (Stage Width) and derivative (Differential) calculation.
• When the thermostat is active (either the heating or cooling stage is on), a
"Working (
• Stage 1 operation will show the icon (
UM-15090500-AA1
)" icon will be shown on the LCD.
). Stage 2 operation will display ( ).
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