Outdoor Disconnect; Install And Adjust Stop Brackets; Range Limiting And Lever Locking Methods - Honeywell T874 Product Data

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
Standard Terminal
Designation
Y
a Other terminal designations can be used that are not listed on this table. Refer to the hookup drawing and internal schematic
for exact connections.
W3 controls the auxiliary heat like W2, and allows adding additional stages of auxiliary heat with outdoor thermostats while
b
maintaining the proper second stage anticipation.

Outdoor Disconnect

The National Electrical Code requires the installation of a
disconnect switch within sight of the outdoor unit of an air
conditioner or heat pump. The switch is for the safety of any
technician working on the unit. The technician can assure that
the unit remains unpowered.

Install and Adjust Stop Brackets

The stop brackets should be installed only if there is a need to
restrict the adjustable range of the heating and cooling
temperature setpoint levers. If adjustable lever stops are
desired, order 4074ECK Envelope Assembly, which contains
two adjustable lever stop brackets, one brass insert, one
HEAT
LEVER
ADJUSTABLE
LEVER STOP
BRACKETS
6. Insert the mounting screw into the two slots in the stop
brackets and attach to the brass insert. Tighten the
screw to pull the brass insert into the back of the ther-
60-2485—8
Table 5. Terminal Designations
Alternate Designations or
Customer Specials
T
R1, R2
RS
M
HOLES FOR INSULATED
LOCKING LEVER SCREWS
COOL
HOLE WITH
LEVER
BRASS INSERT
BRACKET
TABS
MOUNTING
SCREW
BRACKET
SLOTS
ADJUSTABLE STOPS
Fig. 9. Range limiting and lever locking methods.
a
Typical Connection
External temperature readout, T relay
LO and HI speed fan relays
Cooling contactor
Compressor contactor
mounting screw and two locking 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 by pulling the bottom
edge of the cover upward until it snaps free of the
mounting 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 finger.
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
Fig. 9.
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
mostat.
7. Loosen the mounting screw enough to free the stop
brackets for adjustment.
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M7626