Honeywell RTH7400D User manual

OWNER’S GUIDE
Patents Pending
® U.S. Registered Trademark
© 2004 Honeywell International Inc.
All Rights Reserved 69-1726-1
RTH7400D
Programmable Thermostat
The RTH7400D Thermostat provides electronic control of 24 Vac
heating and cooling systems or 750 mV heating systems.
For assistance with your Honeywell product, please visit
www.honeywell.com/yourhome or call Honeywell Customer Care
toll free at 1-800-468-1502.
Read and Save these Instructions

69-1726—1 2
Contents
Prepare for Installation ............................................................ 3
Follow Important Instructions .................................................. 5
Remove Old Thermostat ......................................................... 6
Follow Special Instructions...................................................... 7
Label Old Thermostat Wires ................................................... 10
Mount New Wallplate to Wall .................................................. 11
Connect Wires to New Wallplate............................................. 15
Install Batteries........................................................................ 23
Attach New Thermostat to Wallplate ....................................... 24
Configure Installer Setup......................................................... 26
Customer Assistance .............................................................. 62
Limited One-Year Warranty ..................................................... 63

3 69-1726—1
Step 1. Prepare for Installation
1. Check that the following items are included:
If any of the items shown above are missing, call
Honeywell Customer Care at 1-800-468-1502
before returning the thermostat to the store.
CAUTION
TURN OFF POWER to system at the furnace, or at the fuse/circuit
breaker panel before you begin.
Match the letter of
y
our old thermostat wire with the terminal of th
e
correspondin
g
letter on
y
our new thermostat or base
.
Ó
N
e
ll.
co
m
/
y
ou
rh
o
m
e
B
G
R
V
/
V
R
X
B
G
R
V
/
V
R
H
Y2
H
R
C
W
C
L
RH
W1
X2
E
O
T
W2
F
P
U
W3
Y1
F
P
U
W3
Y1
WALLPLATE
THERMOSTAT
M2227
8
MOUNTING SCREWS (2)
AND WALL ANCHORS (2)
OWNER'S GUIDE
CAUTION CARD
WIRE LABELS
M
on
R
ead
a
n
d
sa
v
e
th
ese
in
s
tr
uc
ti
o
n
s
OWNER'S GUIDE
fusibles-interru
p
tor
t
é

69-1726—1 4
Step 1. Prepare for Installation (Cont)
2. Check that you have everything required for the
installation:
• Two AA alkaline batteries
• No. 2 Phillips screwdriver and standard pocket
screwdriver
•Drill
• Drill bit—use 3/16 in. for drywall; use 7/32 in. for
plaster
• Level (optional)
• Hammer
•Pencil
• Electrical tape

5 69-1726—1
Step 2. Follow Important Instructions
1. Do not connect the wires to the new thermostat
based on wire color because damage can occur to
the heating and/or cooling system.
These Installation Instructions explain later how to
use the enclosed wire labels to correctly mark the
wires connected to your old thermostat.
M22034
Y
G
RC
W
OLD THERMOSTAT
RED
WHITE
YELLOW
ORANGE
GREEN
!
DO NOT WIRE
NEW THERMOSTAT
BASED ON
WIRE COLOR.
R

69-1726—1 6
Step 3. Remove Old Thermostat
1. Turn off power at the heating and/or cooling system
or fuse/circuit breaker panel.
2. Remove the cover from the old thermostat.
3. Remove the old thermostat from the wall or wall-
plate. Do not remove the wires.
MERCURY NOTICE
If you are replacing a thermostat that contains mercury
in a sealed tube, do not place your old thermostat in the
trash.
Contact your local waste management authority for
instructions regarding recycling and the proper disposal
of an old thermostat containing mercury in a sealed
tube.
Y
G
C
R
W
OLD THERMOSTAT
.
1
8
.2
.25 .3
.9
.7
.5
.4
L
O
N
G
E
R
THERMOSTAT
COVER
WALLPLATE
M22036

7 69-1726—1
Step 4. Follow Special Instructions
1. If you have two C and/or C1 wires connected to
your old thermostat, do not connect them to your
new thermostat.
2. Disconnect the C and/or C1 wires. Make sure they
do not touch each other or any other wires.
3. Wrap the bare end of each C and/or C1 wire with
electrical tape.
Y
C
C
R
W
OLD THERMOSTAT
WIRE HOLE
M22201
DO NOT CONNECT TO NEW
THERMOSTAT
WIRE
SCREW
TERMINAL
LETTER
DESIGNATION
G

69-1726—1 8
Step 4. Follow Special Instructions (Cont)
4. If you have only one C and/or C1 wire connected to
your old thermostat, connect this wire to C on the
new thermostat.
Y
C
R
W
OLD THERMOSTAT
WIRE HOLE
M22223
CONNECT TO THE "C" ON THE
NEW THERMOSTAT
WIRE
SCREW
TERMINAL
LETTER
DESIGNATION
G

9 69-1726—1
Step 4. Follow Special Instructions (Cont)
5. If you find any wires not connected to your old
thermostat, do not connect them to your new
thermostat.
6. Wrap the end of the wires that are not connected
with electrical tape.
Y
G
RC
R
OLD THERMOSTAT
WIRE HOLE
WIRES NOT CONNECTED –
DO NOT CONNECT TO
NEW THERMOSTAT M22040
WIRE
SCREW TERMINAL
LETTER DESIGNATION
W

69-1726—1 10
Step 5. Label Old Thermostat Wires
1. As you disconnect each wire, use the enclosed wire
labels to wrap a wire label around each wire that
matches the letter designation. Do not allow the
wires to fall into the wall opening after the wires are
disconnected.
2. Remove any remaining part of the old thermostat
from the wall.
When connecting the wires to the new
thermostat, refer to the wire labels. Do not
connect wires to your new thermostat based on
the color of the wire.
Y
G
R
C
R
OLD THERMOSTAT
WIRE HOLE
M22039
WIRE
SCREW
TERMINAL
LETTER
DESIGNATION
WIRE LABEL
W
W
G
Y
R
RC