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UM-15093500-AA1
3 Installation
The BASstat 421C-BW2 is intended for surface-mount installation on an interior wall, away from
direct sunlight or direct air movement. The display (top half) can be removed from its base by
loosening the small Philips screw at the bottom of the display. Once the display is removed from
the base, the base can be mounted onto the wall with appropriate fasteners. If a single-gang
electrical junction box is to be used, the top and bottom mounting holes will align with the screw
holes in the junction box.
3.1
Terminal Block Pin Assignments
Two terminal blocks are provided for all field connections. The remote sensor input (RS) is at
terminals 13 and 14. The remote occupancy (ESI) input is a dry contact closure input located at
terminals 14 and 15.
Number
Mark
Comment
Number
Mark
Comment
1
R
24 VAC high-side
10
AO1
Cooling Device
2
C
24 VAC common
11
COM
3
12
AO2
Heating Device
4
13
RS
Remote Sensor Input
5
14
COM
Sensor Common
6
15
ESI
Energy Saving Input
7
16
8
G
Fan
17
9
18
3.2
Limited Power Source
The BASstat is intended to be powered by a Class 2 compliant power source and only accepts
24VAC with no more than 5VA of power consumption. It should be powered by a Class 2 power
source complying with the requirements of the National Electric Code (NEC) article 725. The
transformer or power supply complying with the Class 2 rating must carry a corresponding
listing from a regulatory agency such as Underwriters Laboratories (UL).