Johnson Controls T25 User Manual

Application
T25 thermostats are for line or
low voltage service requiring
accurate control of two operating
functions. Choice of functions
include:
• control of two stages of
heating, such as two-rate
unit heaters or duct furnaces,
commercial heat pumps, etc.
• control of two-stages of
cooling, such as two-stage
compressors, dual
compressor units, etc.
• automatic changeover
control of heating and
cooling on three and four
pipe fan coil installations and
similar applications;
automatic changeover from
heating to cooling for unit
operation
Specifications
© 1982 Johnson Controls, Inc.
Code No. LIT-125640
T25 Type Two-Stage Room Thermostat
Low or Line Voltage--Also for Automatic
Changeover of Heating and Cooling
All Series T25 thermostats 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 or
systems that protect against,
or warn of, a control failure.
Typical uses are for compressor
control, fan coils, etc. Two
SPDT switches permit
independent control circuits.
Each switch may be wired to
make or break the control circuit
on rise in temperature. A
removable jumper across the
"common" terminals is supplied
as standard.
Features
• Contact units are
dependable, dusttight, field
proven Pennswitches.
• A sensitive liquid charged
element and an efficient
lever mechanism provides
close operating differential
without anticipators.
Master Catalog 125
Room Thermostats Section T
Product Bulletin T25
Issue Date 1182
Fig. 1 -- T25 Two-Stage
Thermostat.
• A bimetal thermometer is
standard.
• A semi-concealed high
temperature stop, which can
be set in the field, is built-in
feature of the thermostat.
•
Attractive style matches
other Johnson Controls
thermostats and humidistats.
General Description
T25 thermostats have pleasing,
contemporary styling that is
adaptable to any decor. The
thermometer is a dependable
easy reading, bimetal pointer
type.
The liquid charged sensing
element is formed to achieve
maximum sensitivity to
surrounding air temperature
changes. (See Fig. 2.) Coupled
with a highly efficient diaphragm
and lever mechanism, the
element actuates totally
enclosed Pennswitch contact
units to provide a low operating
differential and dependable
switching action without the
necessity of either heating or
cooling anticipators.
1