Bryant T874 Thermostat User Manual


 
PRODUCT DATA
60- 248
5
-
8
® U.S. Re
g
istered Trademark
Cop
y
ri
g
ht © 2001 Hone
y
well • All Ri
g
hts Reserved
T874 Multistage Thermostats
and Q674 Subbases
APPLICATION
These thermostats and subbases provide low volta
g
e control
of multista
g
e heatin
g
and coolin
g
s
y
stems, includin
g
heat
pump s
y
stems.
FEATURES
T874 Thermostat has silent, dust-free mercury
switches operated by coiled bimetal elements.
Heat anticipator(s) are adjustable or fixed cooling
anticipator(s) are fixed.
Individual heat and cool levers and scales (most
models) for temperature setting located on top of
thermostat case.
Cover thermometer on most T874 Multistage
Thermostat models.
Locking cover and locking lever screws available for
T874 Multistage Thermostats.
Versaguard™ Thermostat Guard or custom key lock
thermostat guards available for T874 Multistage
Thermostats.
T874 Thermostat requires a Q674 Subbase.
Q674 Subbase provides system and fan switching,
wiring terminals and mounting base for T874
Multistage Thermostat.
Adapter plate available for mounting Q674 on wall or
horizontal outlet box.
Light-emitting diodes (LEDs) located on subbase for
easy reference.
Up to three stages each of heating and cooling control
possible.
Models with setpoint restrictions and locking cover
with no thermometer available for Department of
Defense (DoD) and other special applications.
Outdoor reset used on some models to improve
thermal performance.
Contents
Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Understanding Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Cross Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96