Heat Pump Thermostat
The T8411R Heat Pump Thermostat provides 24V
control of two-stage heating and one-stage cooling heat
pump system with manual changeover from heat to cool.
First stage heating and cooling cycle rates are fixed at
3 cph. Second stage heating cycle rate is selectable at
3, 4, 5, 6, 9 or 12 cph. Temperature indication can be set
for °F or °C.
The T8411R Heat Pump Thermostat is powered directly
from the system transformer. Batteries are not required
because setpoints are held permanently by non-volatile
memory.
The T8411R includes a thermostat, wallplate (for wiring
and mounting thermostat), and owner’s guide. A 7 3/8 in.
x 5 3/4 in. (188mm x146 mm) decorator cover plate (for
covering wall marks) is available separately. Order
Honeywell part no. 209649A (taupe color).
MERCURY NOTICE
If this control is replacing a control that contains
mercury in a sealed tube, do not place your old
control in the trash.
Contact your local waste management authority
for instructions regarding recycling and the
proper disposal of an old control containing
mercury in a sealed tube.
INSTALLATION
When Installing this Product…
1. Read these instructions carefully. Failure to follow
them could damage the product or cause a hazardous condition.
2. Check the ratings given in the instructions and on
the product to make sure the product is suitable for
your application.
3. Installer must be a trained, experienced service
technician.
4. After installation is complete, check out product
operation as provided in these instructions.
T8411R Electronic
INSTALLATION INSTRUCTIONS
CAUTION
Electrical Shock or Equipment Damage
Hazard.
Can shock individuals or short equipment
circuitry.
Disconnect power supply before installation.
Location
Install the thermostat about 5 ft (1.5m) above the floor in
an area with good air circulation at average temperature.
See Fig. 1. Do not install the thermostat where it can be
affected by:
— drafts or dead spots behind doors and in corners.
— hot or cold air from ducts.
— radiant heat from the sun or appliances.
— concealed pipes and chimneys.
— unheated (uncooled) areas such as an outside wall
behind the thermostat.
This thermostat is a precision instrument and was
carefully adjusted at the factory. Handle it carefully.
Mounting Wallplate to Wall
IMPORTANT
Level only for appearance. The thermostat functions normally even when not level.
Mount wallplate, T8411R and the screws provided (see
Fig. 2) as follows:
1. Place the wallplate at the desired location on the
wall.
2. Use a pencil to mark the mounting holes.
3. Remove the wallplate from the wall and drill two
3/16 in. holes in the wall (if drywall) or two 7/32 in.
holes for firmer material such as plaster or wood.
4. Gently tap the anchors (provided) into the holes
until flush with the wall.
5. Position the wallplate over the holes.
6. Pull the thermostat wire through the wallplate
entrance hole.
7. Fasten the wallplate to the wall using the anchors
and screws provided.
® U.S. Registered Trademark
Copyright © 2002 Honeywell • •All Rights Reserved
69- 1486- 1
T8411R ELECTRONIC HEAT PUMP THERMOSTAT
NO
NO
Fig. 1. Typical location of thermostat.
WALL
MOUNTING
SCREWS (2)
1
WHEN USING WALL ANCHORS, DRILL 3/16 INCH
HOLES FOR DRYWALL, 7/32 INCH HOLES FOR
PLASTER OR WOOD.
WALL
ANCHORS (2)
1
WALLPLATE
M12202A
Fig. 2. Mounting wallplate to wall.
Wiring
IMPORTANT
Use an 18-gauge maximum wire for wiring the
T8411R Thermostat.
All wiring must comply with local electrical codes and
ordinances.
CAUTION
Electrical Shock or Equipment Damage
Hazard.
Can shock individuals or short equipment
circuitry.
Disconnect power supply before installation.
YES
5 FEET
[1.5 METERS]
The shape of the terminals permits insertion of straight or
wraparound wiring connections; either method is
acceptable. See Fig. 3.
TERMINAL
SCREW
NO
M11338
FOR STRAIGHT INSERTION
STRIP 5/16 IN. (8 MM)
FOR WRAPAROUND
STRIP 7/16 IN. (11 MM)
G
L
C
R
W2
E
W1
B
Y
NOT ALL MODELS HAVE BOTH O AND B TERMINALS.
1
Fig. 3. Wiring connections.
NOTE: To ensure proper mounting of thermostat,
restrict all wiring to the shaded area. See Fig. 4.
1
O
M11334A
69-1486-1 2
T8411R ELECTRONIC HEAT PUMP THERMOSTAT
KEEP WIRING IN
SHADED AREA
G
C
R
W1
Y
MOUNTING
SCREW HOLE
1
WIRING ENTRANCE
HOLE
NOT ALL MODELS HAVE BOTH O AND B TERMINALS.
L
W2
E
B
1
O
MOUNTING
SCREW HOLE
M11331A
Refer to Fig. 5 for typical wiring hookups. A letter code is
located near each terminal for identification.
1. Loosen the terminal screws on the wallplate and
connect the system wires. See Fig. 5.
2. Securely tighten each terminal screw.
3. Push the excess wire back into the hole.
4. Plug the hole with nonflammable insulation to pre-
vent drafts from affecting the thermostat.
Mounting Thermostat to Wallplate
1. Engage the tabs at the top of the thermostat and
wallplate.
2. Swing down the thermostat and press the lower
edge of the thermostat onto the wallplate to latch.
See Fig. 6.
Fig. 4. Restrict wiring to shaded area.
THERMISTOR
SENSOR
THERMOSTAT
LOGIC
POWER
SUPPLY
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
1
2
REMOVE JUMPER, WHEN SUPPLIED, FOR SYSTEMS WITH SEPARATE HEATING COMPRESSOR CONTACTOR (W1 SEPARATE FROM Y).
3
NOT ALL MODELS HAVE BOTH O AND B TERMINALS.
STAGE 2 RELAY
STAGE 1 RELAY
FAN SWITCH
ON
AUTO
SYSTEM
SWITCH
EM. HT.
HEAT
OFF
COOL
R
W2
L
B
3
O
Y
2
W1
E
G
C
Fig. 5. T8411R two-stage heat and one-stage cool wiring diagram with manual changeover.
3 69-1486-1
AUXILARY
HEAT RELAY
CHANGEOVER
VALVE HEAT
COMPRESSOR
CONTACTOR
COMPRESSOR
CONTACTOR
HEAT
EMERGENCY
HEAT RELAY
RELAY
CHANGEOVER
VALVE COOL
FAN RELAY
M11333A
L1
(HOT)
L2
1
T8411R ELECTRONIC HEAT PUMP THERMOSTAT
Em Ht Aux Ht
Set Room
F
A
N
A
u
to
O
n
C
ool O
A
ENGAGE TABS AT TOP OF THERMOSTAT
WITH SLOTS ON MOUNTING PLATE.
E
m
H
t A
u
x H
t
S
e
t R
o
o
m
F
A
N
A
uto
O
n
DASHED LINES INDICATE TABS
ON BACK OF THERMOSTAT
S
YSTEM
ff H
eat Em
H
t
Cool Off Heat Em Ht
S
Y
S
T
E
M
FAN Switch
Fan switch settings are:
On: The fan runs continuously. Use for improved air
circulation and air quality.
Auto: Normal setting for most homes. The fan starts
and stops with the equipment.
Slide the FAN switch in the bottom left corner of the
thermostat to select the desired fan setting.
SYSTEM Switch
System switch settings control thermostat operation as
follows:
Cool: The thermostat controls the cooling system.
Off: Both heating and cooling are off.
Heat: The thermostat controls the heating system.
Em Ht: Thermostat cycles auxiliary heat (W2) and
emergency heat relay (E) as needed to maintain
setpoint. Terminal L is energized continuously.
Fault heat relay is on continuously. Cooling system
is off. Compressor is de-energized.
Slide the SYSTEM switch in the bottom right corner of
the thermostat to select the desired system setting.
TEMPERATURE DISPLAY
INCREASE SETTING
DECREASE SETTING
Em Ht Aux Ht
Set Room
PRESS LOWER EDGE OF
B
CASE TO LATCH.
M18541
Fig. 6. Mounting thermostat wallplate.
OPERATION
Setting FAN and SYSTEM Switches
Fan and system settings are controlled manually by
using the switches located at the bottom of the
thermostat case. See Fig. 7.
69-1486-1 4
FAN
Auto On
SYSTEM
C
o
SYSTEM SWITCH
o
l O
ff H
e
a
t E
m
H
t
M18542
FAN SWITCH
Fig. 7. Digital display and system
switches (FAN and SYSTEM).
Em Ht and Aux Ht Indications
The ▲ indicator points to either Emergency Heat (Em Ht)
or Auxiliary Heat (Aux Ht) when these modes are active.
Em Ht: The ▲ indicator points to Em Ht when the
SYSTEM switch is set at Em Ht.
Aux Ht: The ▲ indicator points to Aux Ht when the
auxiliary backup heat is needed to help handle
the heating load.
INDICATOR
Set
Em Ht
Room
M18425
T8411R ELECTRONIC HEAT PUMP THERMOSTAT
Set Temperature Setpoint
NOTE: Temperature setpoint range is 40° to 99°F (4° to
39°C).
The temperature setpoint and the room temperature are
shown separately on the digital display. The ▼ indicator
points to Set when the temperature setpoint is displayed
and to Room when the room temperature is displayed
.
INDICATOR
ROOM TEMPERATURE
Room
Set
SETPOINT TEMPERATURE
To set temperature setpoint:
1. Select Heat or Cool by sliding the SYSTEM switch
in the lower right corner of the thermostat to the
desired mode. See Fig. 7.
2. To display the temperature setpoint on the digital
display, press either the ▲ or ▼ key once. The
temperature setpoint is displayed for approximately five seconds as the indicator points to Set
and flashes.
M14680
3. To increase the temperature setpoint press the ▲
key. Each press changes the setpoint one degree;
press and hold to change the setpoint several
degrees.
M14681
4. To decrease the temperature setpoint press the ▼
key. Each press changes the setpoint one degree;
press and hold to change the setpoint several
degrees.
M14679
2. Press the ▲▼ keys simultaneously for more than
one second to light all segments on display and to
enter installer setup mode. When the keys are
released, a two-digit software revision code is displayed.
M18426
OPTIONAL SYSTEM CHECKOUT
When the heat or cool outputs are turned on, the fiveminute off-timer safety feature is bypassed.
When in steps 2 and 3 only, the
turn heat or cool outputs on and off. Change the
SYSTEM switch setting to test heat or cool outputs. No
action takes place If the system switch is in the Off
position.
The following examples of system settings show a two
digit software code on the display. The code shown is
only an example; codes may vary.
System setting at Heat:
To turn heat on, press the ▼ key.
▼
key can be used to
M18431
To turn auxiliary heat on, press the ▼ key.
Aux Ht
To turn auxiliary heat off, press the ▼ key a third time.
M18432
M18433
To turn heat off, press the ▼ key a fourth time.
M14682
Setting °F/°C Indication and Heat Cycle Rate
NOTE: To save changes to the °F/°C indication and the
heat cycle rate, all seven steps must be completed.
In installer setup mode, steps 2 through 5, each
press of the ▲ key momentarily displays 01 and
each press of the ▼ key momentarily displays
02. When the keys are released, these two-digit
codes are no longer displayed.
To set the °F/°C indication and heat cycle rate:
1. If the temperature is displayed in °F, set the temperature setpoint to 52°F. If the room temperature
is displayed in °C, set the temperature setpoint to
11° C.
M14683
M18434
System setting at Cool:
To turn cool on, press the ▼ key.
M18435
To turn cool off, press the ▼ key.
M18434
3. Press the ▲ key. Factory information is displayed.
A typical example is shown, but information displayed varies by model. This information is for factory use only.
4. Press the ▲ key again to display °C or °F.
M14688
5 69-1486-1
T8411R ELECTRONIC HEAT PUMP THERMOSTAT
5. Press the ▼ key to change the °C or °F indication.
M14689
NOTE: Stage-one heat and cool cycle rates are fixed at
3 cph. Only stage-two heat cycle rates are
selectable.
6. Press the ▲ key to display the heat cycle rate of 3,
4, 5, 6, 9 or 12. If the desired cycle is displayed,
see Table 1, press the ▲ key to exit the installer
setup mode. To change the heat cycle rate, press
the ▼ key to scroll between 3, 4, 5, 6, 9 and 12.
Stop scrolling when the desired rate is displayed.
M14690
Table 1. Heat Cycle Rates.
System Cycle Per Hour
Hydronic heat, condensing gas
a
furnace
3
Gas or oil forced air 6
Electric heat 9
Special applications
a
High efficiency furnace.
b
Refer to equipment manufacturer’s instructions.
7. Press the ▲ key to display cooling algorithm con-
figuration default.
b
4, 5, 12
or
M18421
8. Press the ▲ key again to change cooling algorithm
to C1 or C3.
C1 = Standard cooling algorithm.
C3 = Aggressive cooling algorithm (can cause
9. Press the ▲ key again. Current configuration (CC)
overshooting).
is displayed. A typical example is shown, but CC
varies by model. (This information is for factory use
only.)
10. Press the ▲ key to save all changes, exit installer
setup mode and return to normal operation.
NOTE: After exiting installer setup mode, change the
setpoint to the desired room temperature.
CHECKOUT
Heating
1. Slide the SYSTEM switch to Heat and the FAN
switch to Auto.
2. Press and hold the ▲ key to raise the temperature
setting several degrees above the room temperature. After approximately five minutes, the heating
equipment should start.
3. Press the ▼ key to lower the temperature setting
below the room temperature. Heating equipment
should stop.
Cooling
CAUTION
Equipment Damage Hazard.
Operating at too low of an outdoor
temperature may cause compressor damage.
Do not operate cooling if outdoor temperature is
below 50°F (10°C). Refer to manufacturer ’s
recommendations.
• For compressor protection, allow the
compressor to remain off for five minutes
before restarting.
1. Slide the SYSTEM switch to Cool and the FAN
switch to Auto.
2. Press the ▼ key to lower the temperature setting
several degrees below the room temperature. After
approximately five minutes, the cooling equipment
and fan should start.
3. Press the ▲ key to raise the temperature setting
above the room temperature. Cooling system
should shut down.
Fan
1. Slide the SYSTEM switch to Off and the FAN
switch to On. The fan should run continuously.
2. Slide the FAN switch to Auto. The system turns the
fan on and off with the equipment.
Make certain all equipment responds properly to the
thermostat.
M18420
Automation and Control Solutions
Honeywell Honeywell Limited-Honeywell Limitée
1985 Douglas Drive North 35 Dynamic Drive
Golden Valley, MN 55422 Scarborough, Ontario
69-1486-1 G.H. Rev. 2-02 Printed in Mexico www.honeywell.com/yourhome
M1V 4Z9
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