Honeywell T874 ユーザーズマニュアル

60-2485—8

10

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.

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 

mounting screw and two locking screws with insulated heads. 

When installed, the stop brackets limit the movement of the 

T874 HEAT and COOL levers.

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.

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-

mostat.

7. Loosen the mounting screw enough to free the stop 

brackets for adjustment.

T

External temperature readout, T relay

R1, R2

LO and HI speed fan relays

RS

Cooling contactor

Y

M

Compressor contactor

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.

b

W3 controls the auxiliary heat like W2, and allows adding additional stages of auxiliary heat with outdoor thermostats while 

maintaining the proper second stage 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