Submittal Sheet

AT120A-E; AT140A-E; AT150A,B,D-F; AT160B; AT175A-D,F TRANSFORMERS
© 2021 Resideo Technologies, Inc. All rights reserved.
This product is manufactured by Resideo Technologies, Inc. and its affiliates.
www.resideo.com
Resideo Technologies, Inc.
1985 Douglas Drive North, Golden Valley, MN 55422
1-800-468-1502
68-0054—06 M.S. Rev. 03-21 | Printed in United States
CHECKOUT
CAUTION
Do not short transformer secondary terminals.
Overload current protection inherent on AT120,
AT140, and AT150. 3.5 Amp fuse available on AT160B
and AT175A-D.
Voltage Check
After installation is complete, turn on power supply and
perform a voltage check.
1. Place the controlled equipment in operation and
observe through one complete cycle.
2. Using a voltmeter, verify proper primary and secondary
voltages.
3. If voltage readings are incorrect, ensure primary volt-
age connections are made properly (refer to Fig. 18).
4. Measure voltage again.
a. If proper primary voltage is measured and second-
ary voltage is significantly less than the voltage
shown on the regulation curves, transformer wind-
ing is damaged. Replace transformer and repeat
checkout procedures.
b. If primary voltage is 0V, make sure power supply is
connected properly or repair if necessary. Repeat
checkout procedures.
5. Do not put the system into operation unless correct
primary and secondary voltages are measured.
Circuit Breaker (AT150F, AT175F
Models only)
Overloading the AT150F or AT175F Transformer results in
tripping the circuit breaker. If the secondary side of the
transformer is short circuited, the circuit breaker trips in less
than one minute. Reset the circuit breaker by pressing the
reset button on the top of the transformer. It can take up to
one hour for the transformer to cool, allowing it to reset. If the
circuit breaker continues to trip, thoroughly check the system
for short circuits and the current draw.