T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—810
Outdoor Disconnect
The National Electrical Code re
uires the installation of a
disconnect switch w
ithin
si
ht of the outdoor unit of an air
conditioner or heat pump. The switch is for the safet
of an
technician workin
on the unit. The technician can assure that
the unit
remains
unpowered.
Install and Adjust Stop Brackets
The stop brackets should be installed onl
if there is a need to
restrict the ad
ustable ran
e of the heatin
and coolin
temperature setpoint levers. If ad
ustable lever stops are
desired, order 4074ECK Envelope Assembl
, which contains
two ad
ustable lever stop brackets, one brass insert, one
mountin
screw and two lockin
screws with insulated heads.
When installed, the stop brackets limit the movement of the
T874 HEAT and COOL levers.
TO INSTALL:
1.
Remove the thermostat cover b
pullin
the bottom
ed
e of the cover upward until it snaps free of the
mountin
slots.
2.
Turn to the back of the T874 Thermostat. Locate the
hole for the brass insert in the plastic base below the
LED window.
3.
Push the brass insert into the hole with fin
er.
4.
Turn to the front of the T874 Thermostat.
5.
Place the two stop brackets in position with the tabs in
the slot between the HEAT and COOL levers. See
Fi
. 9.
Fig. 9. Range limiting and lever locking methods.
6.
Insert the mountin
screw into the two slots in the stop
brackets and attach to the brass insert. Ti
hten the
screw to pull the brass insert into the back of the ther-
mostat.
7.
Loosen the mountin
screw enou
h to free the stop
brackets for ad
ustment.
T External temperature readout, T rela
R1, R2 LO and HI speed fan rela
s
RS Coolin
contactor
Y M Compressor contactor
Table 5. Terminal Designations
a
Standard Terminal
Designation
Alternate Designations or
Customer Specials Typical Connection
a
Other terminal desi
nations can be used that are not listed on this table. Refer to the hookup drawin
and internal schematic
for exact connections.
b
W3 controls the auxiliar
heat like W2, and allows addin
additional sta
es of auxiliar
heat with outdoor thermostats while
maintainin
the proper second sta
e anticipation.
HEAT
LEVER
HOLES FOR INSULATED
LOCKING LEVER SCREWS
COOL
LEVER
HOLE WITH
BRASS INSERT
BRACKET
TABS
ADJUSTABLE
LEVER STOP
BRACKETS
BRACKET
SLOTS
MOUNTING
SCREW
ADJUSTABLE STOPS
ADJUSTABLE LOCKING LEVERS
NONADJUSTABLE STOPS
WITH LOCKING LEVER SCREWS
75°F (24°C) MAX. HEAT
75°F (24°C) MIN. COOL
NONADJUSTABLE D.O.D. STOPS
72°F (22°C) MAX. HEAT
78°F
26°C
MIN. COOL
M7626
