Introduction - Contemporary Controls BASstat BAST-221C-BW2 User Manual

1 Introduction

The BAST-221C is a member of the BASstat BACnet Communicating Thermostat series. It
provides multi-stage heating and cooling control in an attractive wall-mounted enclosure with a
large LCD display. Intended for use with rooftop units (RTUs), the thermostat can control one or two
stages of heating and one or two stages of Direct Expansion (DX) cooling. The BASstat is BACnet
compliant and BTL listed to ensure seamless integration into BACnet networks. The BAST-221C-
BW2 communicates to a BACnet client over Wi-Fi and can be integrated into any 802.11 b/g/n Wi-
Fi network. A large, easy to read LCD display indicates setpoint, space temperature and current
mode of operation using graphical icons.
The BASstat has a built-in space temperature sensor with provision for remote wired 3kΩ NTC
thermistor sensor or temperature value can be sent by another communicating device over the
BACnet network. "221CH" thermostat models support relative humidity reading with a built-in
sensor which is shown on the display and as a BACnet object, as well as a calculated dew point
value as a BACnet object (no control action is taken based on humidity). Both models have five
relays – two for stage heating, two for stage cooling and one for fan. The BASstat is configurable
locally using the Engineering Menu or via a network connection to a BACnet client. Contemporary
Controls' free BACnet Discovery Tool (BDT): www.ccontrols.com/sd/bdt.htm can be used for initial
discovery and configuration of the thermostat over BACnet. Control algorithm parameters such as
deadband, proportional gain, integral rate, stage trip points and stage widths are all configurable.
This BASstat also features configurable short-cycle protection, maximum cycles per hour, fan
control and occupancy selection. All states and pending delays are indicated by graphical icons on
the thermostat display.
The numerous features available in the BASstat can be configured by the systems integrator to
meet user requirements in two different ways. One way is using a button sequence on the
thermostat in order to enter the Engineering Menu - which requires physical access to the
thermostat. Optionally, the buttons could be locked to limit user access to Engineering Menu after
installation is complete. The second method is configuring the thermostat over the BACnet network
using a BACnet client device or software such as Contemporary Controls' free BACnet Discovery
Tool (BDT). All features available are configurable using both methods.
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