ECM Overview and Setup
UNT-SVX07E-EN
85
Manual Fan Speed Switch (FSS)
The adapter allows direct customer interfacing through
the use of terminal strips. Standard interfacing includes:
•
Fan speeds (H, M, L)
•
Variable speed (2–10V) inputs
The standard adapter board eliminates many separate
wiring harnesses in the panel and allows simple, mistake-
proofed single-plug interfacing of:
•
VelociTach motor control board
•
Transformers
•
Motors
•
Valves
•
Dampers
•
Electric heat control
•
Fan speed switches
The manual fan mode switch is available for fan-coil units
that do not have Trane factory-mounted control packages.
This four-position switch (off, high, medium, low) allows
manual fan mode selection and is available wall mounted.
The wall-mounted option is low-voltage using a factory-
wired transformer. A courtesy 10 Vdc supply is provided
for use with an external potentiometer or rheostat. The
10 Vdc supply supports up to 10 mA draw.
TB3 (right five positions) is normally used to provide 24V
hookup to a wall mounted fan speed switch, and to accept
the returns from the switch for High, Medium, and Low
requests.
TB4 (left three positions) is normally used to control the
system with a 0–10 Vdc output from a thermostat/
controller, or a fan control rheostat/potentiometer.
The terminal block functional assignments and polarity
are shown for reference only, and the schematics that ship
with each unit should be consulted before wiring. Wiring
assignments are configured for each unit.
Figure 75.
Standard adapter board field connections
1.
VSP 10V
2.
VSP 0–10V
3.
VSP DC COM
1.
24 Vac Y (hot) (TB3)
2.
24 Vac Y (gnd) (TB3)
3.
High
4.
Medium
5.
Low
Customer low-voltage
interface for fan speeds,
variable fan speed, and
24 Vac supply
3 2 1 5 4 3 2 1
