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Fig. 2 -- Interior of T25. Note
high temperature stop and
convenient wiring terminals.
Elimination of anticipators
makes every thermostat a
"stock" control, which may be
used on single or two-stage
heating and/or cooling over a
wide range of current loads, at
voltages up to 277 V.A.C.
Thermostats are available with
concealed adjustments. All
thermostats have Allen-head
cover screws to discourage
unauthorized tampering.
T25 thermostats have a
concealed high temperature
stop with adjustments in 2°F
(1.1°C) increments between
68°F (20°C) and 80°F (27°C).
This feature prevents
unauthorized people from setting
the thermostat for temperatures
above a pre-determined
maximum.
Operating Temperature
Differential
The operating temperature
differential of any room
thermostat depends on: the
current flowing through the
thermostat (amperage load); the
velocity of air over the
thermostat; the rate of
temperature change to which the
thermostat is subjected; and,
whether the thermostat is
operating heating or cooling
equipment.
Graphs (Fig. 4, 5) show the
operating temperature
differentials of these thermostats
under various electrical load
conditions.
2 T25 Product Bulletin
Fig. 3 -- T25 with concealed
adjustment.
Fig. 4 -- Heating operating
differential for T25.
Fig. 5 -- Cooling operating
differential for T25.
The air velocity was 25 feet per
minute, (.1 m/sec) and the rate
of temperature change was 6°F
(3.3°C) per hour. Higher air
velocities and/or lower rates of
temperature change result in
lower operating differentials.
(See Figs. 4 and 5.)
Optional Constructions
Celsius Dial and Thermometer
Supplied, when specified, at no
extra charge. Thermostat range
of 5 to 30°C. Thermometer
scale 10 to 30°C.
Brand Nameplates
Available on quantity orders.
Check with Customer Service.
Thermostat Guards
Plastic, wire or cast aluminum
guards are available at extra
cost. See GRD Series in the
Johnson Controls Product
Catalog .
Ordering Information
To order, specify:
1.
T25A for thermostat with
knob adjustment.
2.
Specify optional
construction details, as
required:
a.
Concealed dial and
adjustment model.
b.
Celsius dial and
thermometer.
c.
Brand named.
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