Product Overview

A
pplication Overview
IMPORTANT: All A99B Series Sensors are
designed for use only with
operating controls. Where an
operating control failure would
result in personal injury and/or
loss of property, it is the
responsibility of the installer to
add devices (safety, limit controls)
or systems (alarm, supervisory)
that protect against, or warn of,
control failure.
The A99B temperature sensor line offers an
economical solution for a wide variety of
temperature sensing needs in refrigeration and
HVAC applications. Typical temperature sensing
applications and environments include:
• freezers
• display cases
• walk-in coolers
• reach-in coolers
• defrost termination temperature sensing
• condenser fan cycling
• space and return air temperature sensing
• outdoor air sensing
• process cooling and heating
S
ensor Temperature Averaging
Multiple sensors may be wired in a series parallel
arrangement to provide an average temperature
reading in an area when one sensor cannot provide
a representative temperature reading. This can be
accomplished with 4, 9, 16, etc., (2
2
, 3
2
, 4
2
, etc.)
sensors.
In a series parallel arrangement, there must always
be the same number of parallel-connected sensors
as there are series connected sensors.
In Figures 2-4, each parallel leg is represented as a
column of sensors and each series leg as a row of
sensors.
To Controller
Sensor
Sensor
Sensor
Sensor
Figure 2: 4-Sensor Averaging Wiring
To Controller
SensorSensorSensor
Sensor Sensor Sensor
SensorSensorSensor
Figure 3: 9-Sensor Averaging Wiring
To Controller
Se
n
so
r
Sensor
Sensor
Sensor
Se
n
so
r
Sensor
Sensor
Sensor
Se
n
so
r
Sensor
Sensor
Sensor
Se
n
so
r
Sensor
Sensor
Sensor
Figure 4: 16-Sensor Averaging Wiring
2 A99B Series Temperature Sensors Product/Technical Bulletin