T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
3 60-2485—8
Standard Models
T874 THERMOSTATS
Models:
See Table 3.
Electrical Rating:
24 to 30 Vac.
Switching:
Coiled bimetal elements operate mercur
switches.
Temperature Adjustment:
Heatin
and coolin
settin
levers, with separate scales located on top of thermostat
base. Common lever for heatin
and coolin
on T874R;
one coolin
lever on T874E,V; and one heatin
lever on
T874F,Q.
Dimensions:
See Fi
. 1.
Temperature:
Scale Ran
e: 42° to 88°F
6° to 31°C
stan-
dard; optional ran
es available.
Thermometer Range:
42° to 88°F
6 to 31°C
Changeover Differential:
4°F
2°C
minimum between heat-
in
and coolin
5°F [3°C] on T874W
. Levers can be set
apart for
reater separation.
Interstage Differential:
Standard Models: Mechanical differential is 1°F
0.6°C
between heatin
or coolin
sta
es; operatin
differential is
approximatel
1.9°F
1°C
between sta
es in heatin
or
coolin
.
Special Models: See Table 3.
Finish:
Bei
e or Premier White
®
finish.
Mounting Means:
T874 Multista
e Thermostat mounts on
Q674 Subbase. Subbase mounts horizontall
on wall or
outlet box. Mounts on vertical outlet box with optional
193121A Adapter Plate Assembl
.
Fig. 1. T874 Thermostat and Q674 Subbase dimensions in in. (mm).
Optional Specifications (T874 Only):
Temperature scale ran
es are 40° to 75°F
4° to 24°C
heat-
in
and 75° to 90°F
24° to 32°C
coolin
with stop; 44° to
68°F
7° to 20°C
heatin
, 80° to 86°F
27° to 30°C
cool-
in
; 6° to 29°C
43° to 85°F
Celsius scale; 3° to 22°C
38°
to 72°F
and 26° to 32°C
78° to 90°F
coolin
with stop.
Nonad
ustable factor
-added stop limits heatin
setpoint to
72°F
22°C
maximum and coolin
setpoint to 78°F
26°C
minimum.
OEM customer personalization.
Lockin
cover and lockin
lever
see Thermostat Accesso-
ries
.
Thermostat cover without thermometer.
Ad
ustable lockin
temperature stops.
Volta
e heat anticipation for first or second sta
e heat or both.
See Table 3.
Fast c
clin
on heatin
sta
e
s
for electric heat applications.
C815A Outdoor Thermistor for improved performance on
specified models.
Thermostat Accessories:
Lockin
Cover and Lockin
Lever Assembl
: Part no.
194559R with thermometer; 194559S without thermome-
ter. See Fi
. 2. Includes cover, screws, and Allen wrench
for lockin
cover. The screws must be used to assure
proper operation.
Ad
ustable Lever Stop: Part no. 4074ECK; includes lever stop
and screws.
Universal Versa
uard™ Thermostat Guard: Includes wall-
plate, rin
base,
uard cover, tumbler lock, two ke
s and
optional Hone
well lo
o insert. Double-wall construction
provides extra measure of tamper-resistance. Tamper-
resistant lock; ke
cannot be removed without bein
in
locked position. Vents in
uard base allow airflow for opti-
mum thermostat performance. See form 68-0104 for more
information.
— TG511A1000: Clear cover.
— TG511B1008: Opa
ue cover.
— TG511D1004: Painted steel
off-white
cover. See
Fi
. 2.
M5849
FAN
AUTO ON
OFF
EM. HT. HEAT AUTO COOL
(38)
(87)
SUBBASE
THERMOSTAT MOUNTED
ON SUBBASE
SIDE
50 60 70 80
50 60 70 80
50 60 70 80
HEAT COOL
FAN
AUTO ON
OFF
EM. HT. HEAT AUTO COOL
(89)
FRONT
2-3/16 (56)
1-7/8 (48)
3-1/2
5-1/8 (130)
1-1/2
3-9/32 (83)
3-7/16
3/8 (10)
5-5/8 (143)
