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Master Catalog 125
Temperature Controls Section A
Product Bulletin A70, A72
Issue Date 0996
© 1996 Johnson Controls, Inc.
1
Code No. LIT-125155
A70, A72 Series Temperature Controls
for Refrigeration and Heating
Application
The A70 single-pole and A72
two-pole controls are supplied in a
wide selection of ranges to meet
most application needs. See
“Temperature Ranges.”
Models may be supplied to open
a circuit on temperature increase
or close a circuit on temperature
increase as required. An A70
single-pole control may optionally
include a separate reverse-acting
auxiliary contact. Models are
available with a SPDT enclosed
Pennswitch.
All Series A70, A72 controls are
designed for use
only
as
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 systems) that
protect against, or warn of,
control failure.
Features
•
Long life contact structure with
high contact force right up to
break -- no bounce on make.
•
Make reset models are
“trip-free”.
•
Ranges available to cover
most applications.
•
Auxiliary contact can be used
to actuate an alarm circuit
when the main contact opens.
•
Two-pole construction
provides a number of
application advantages (see
“General Description”).
•
Heavy gauge “low profile”
stainless steel element cup to
protect against mechanical
damage.
Fig. 1 -- Single function
temperature control, Style 1.
General Description
The A70 controls provide
dependability and quality at
attractive prices. The A72 DPST
controls provide a number of
application advantages such as:
• Control of polyphase motors
without use of magnetic
starters where protection
against overloading and single
phasing is otherwise provided.
• Provides two separate control
circuits necessary for the
control of multiple systems.
• One set of contacts breaks the
“hot” line when wired as a two-
pole switch in single-phase
circuits.
• Permits control of two
separate load circuits.
• Automatic control of heavy
electrical loads.
• All A70, A72 controls have a
single calibrated scale which
shows directly both cut-in and
cutout settings. Adjustments
can be made readily without
removing the cover.
Specifications