Honeywell TRADELINE T8400C User manual

T8400C
ElectronicThermostat
The T8400C provides single-stage, non-programmable
temperature control for 24V heating-cooling systems with
manual changeover from heat to cool. Heating cycle rate
is selectable at t, 3, 4, 5, 6, 9, or 12 cph Cooling cycle
rate is fixed at 3 cph Temperature indication can be set
for °F
or °C
The T8400C Thermostat is powered through the heating/
cooling system controls. Batteries are not required
because setpoints are held permanently by non-volatile
memory
T8400C models include a thermostat, wallplate and
owner's guide
MERCURYNOTICE
If this control is replacing a control that contains
mercury in a sealed tube, do not place your old
controt 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 hazard-
ous 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
CAUTION
Electrical Shock or Equipment Damage
Hazard,
Can shock individuals or short equipment
circuitry.
Disconnect power supply before installation
Location
_nstall the thermostat about 5 ft (15m) 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 co{d 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 func-
tions norFnally even when not level
NOTE: T8400C models include a thermostat and wall-
plate
Mount wallplate, T8400C. and the screws provided (see
Fig 2) as follows:
1. Place the wallplate at the desired location on
the wall
2. Pull the thermostat wire through the wallplate
entrance hole
3. Select the two mounting holes that best fit the
application
4. Fasten the wallpiate to the wall using the anchors
and screws provided
5. After widng the waHplate, plug the hole to prevent
drafts from affecting the thermostat; see Widng
section
Copyright (© 2002 •@.All Rights Reserved IIIIIIIIIIIIIIIIIIIIII 69-1485-1

T8400C ELECTRONIC THERMOSTAT
1
5_£ET
[1,5METERS]
!
J
Ji
/
/
Fig. 1, Typical location of thermostat.
_ DR_LL 3/_6 INCH HOLgS 0g DRYWALL/OR 7/32 (PLASTER OR WOOD)
WHEN USING WALL ANCHORS M1_88
Fig. 2. Mounting wallplate to wall.
Wiring
IMPORTANT
Use an 18-gauge maximum wire for wiring the
T840gC Thermostats
AII wiring must comply with local electrical codes and
ordinances Disconnect the power supply to prevent
electrical shock or equipment damage
NOTE: To ensure proper mounting of thermostat,
restrict aft wiring to the shaded area on the left
side of the terminals See Fig. 3
The shape of the terminals permits insertion of straight or
wraparound wiring connections; either method is
acceptable See Fig 4.
The T84000 Thermostat is powered through the heating/
cooling system controls and is adaptable to most 4-wire,
18 to 30 Vac heating-cooling systems Refer to Fig 5 and
6 for typical wiring hookups.
- KEEPW_R_NGIN
SHADEDAREAf-- ALTERNATEMOUNT_NG
/SCREW_€gLE
SCREW
HOLE
MOUNTING
SCREWHOLE
_""_L W_I_]NG ENTRANCE HOLE
MOUNTING Ml1023
SCRBWHOlE
Fig. 3. Restrict wiring to shaded area,
69-1485-1 2

STR_P5/16_N.(eMM)
Fig. 4. Wiring connections.
T8400C
_ POWERSt_PpLy_PROWOED_SCONNECTMEANSAND
OVERLOAD_OTECT_ONASREQUIRED_ M109_
Fig. 5. T8400C heat-cool wiring diagram in single
transformer system with gas heat/electric cooling.
Te400C
Z_ POWERSt_PpLy_PROWDED_SCONNECTMEAN_ANO
OVERLOADPROTECTK)NASREQU_RED_ M10_7
Fig. 6. T8400C beat-cool wiring diagram in
og heating/electric cooling system. Oil
primary has its own transformer.
T8400C ELECTRONIC 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 _ower
edge of the thermostat onto the wallplate to latch.
See Fig 7.
DASHEDL_NES_NOICA_TABS
A ENGAGETA£SATTOP
OFT_4ERMOSTATW_TH
SLOTSONWALLPLATE
M18416 B PRESSLOWEREDGEOF
CASETO£AT¢_4
Fig= 7. Mounting thermostat wallplate.
OPERATION
Setting FAN and SYSTEM Switches
Fan and system settfngs are controfled manuafly by
using the switches located at the bottom of the
thermostat case See Fig 8
FAN Switch
Fan switch settings are:
On: The fan runs continuously Use for improved air
circulation and air quality
Auto: Norma_ setting for most homes In cooling, the
fan starts and stops with the cooling equipment. In
heating, the fan is controlled directly by the heating
equipment and may start a few mfnutes after the
heating equipment turns on (on most systems)
When using an electric heat thermostat, the fan
starts and stops wdh the heating equipment
Slide the 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
Slide the switch in the bottom right corner of the
thermostat to select the desired system setting
3 69-1485-1

T8400C ELECTRONIC THERMOSTAT
FTEMPERATUREDISPLAY
jr _NCREASE
SETtiNG
DECREASE
SETtiNG
'_- FAN_Wb_CH
Fig. 8. Digital display and system
switches (FAN and SYSTEM).
Set Temperature Setpoint
NOTE: Temperature setpoint range is 40 ° to 99°F (5 to
37°C)
The temperature setpoJnt 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
To set temperature setpoJnt:
1, Select Heat or Cool by sliding the SYSTEM switch
in the _ower right corner of the thermostat to the
desired mode See Fig 8.
2, To display the temperature setpoint on the digital
display, press either the •or • key once. The
temperature setpoint is displayed for approxi-
mately 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
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 com-
pleted
To set the °F/°C indication and heat cycle rate:
1. If the temperature is displayed in °E set the tem-
perature setpoint to 52°F If the room temperature
is displayed in °C, set the temperature setpoint to
11C
M14_3
OPTIONALSYSTEMCHECKOUT
When in steps 2and 3 onlj4 the •key can be used to
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 systet'n switch is in the Off
losiflon
Examples: System setting at HEAT: if heat is on. the •
key turns it off; if heat is off. • turns it on
System setting at COOL: If cool is on, • key
turns itoff; if cool is off, • turns it on
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 dis-
played.
M148_
NOTE: In installer setup mode only, each press of the
• key momentarily displays 01. Each press of
the • key momentarily displays 02 When the
keys are released, these two-digit codes are no
longer displayed.
69-1485-1 4

3, Press the • key. Factory information is displayed
A typical example is shown, but information dis-
played varies by mode_ This information is for fac-
tory use only
M14_7
4. Press the • key again to display C or F
M14_8
5. Press the • key to change the C or °F indication
M14_9
6. Press the • key to display the heat cycle rate of 1,
3, 4, 5, 6, 9, or f 2 ffthe desired cycle is displayed,
press the • key to exit the installer setup mode To
change the heat cycle rate, press the • key to
scroll between 1, 3, 4, 5, 6, 9, or 12. Stop scrolling
when the desired rate is displayed See Table 1 for
the cycle rate options and the corresponding sys-
tem equipment
M14690
7, Press the • key to display cooling algorithm con-
figuration default
M1_19
8. Press the • key again to change cooling algorithm
to Cl or C3.
Cl = Standard cooling algorithm
C3 = Aggressive cooling algorithm (can cause
overshooting).
g. Press the • key again. Current configuration (CC)
is displayed. A typical example is shown, but CC
varies by model (This information is for factory use
only)
M1_20
Table 1, Heating Cycle Rates.
System
Steam, gravity
Hydronic heat, condensing gas
furnace a
Gas or oil forced air
Electric heat
Special applications b
aHigh efficiency furnace
bRefer to equipment manufacturer's instructions
Cycles Per Hour
1
3
6
9
4,5,12
T8400C ELECTRONIC THERMOSTAT
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 tempera-
ture After approximately ten seconds, the heating
equipment should start. In conventional systems.
the system turns on the fan through the use of a
time delay relay or through a limit control When
using an electric heat thermostat, the fan starts
immediately
3. Press the • key to lower the temperature setting
below the room temperature Heating equipment
should stop
Cooling
zLCAUTION
Low Temperature Hazard.
Operating at too low of an outdoor
temperature may cause compressor damage.
Do not operate cooling if outdoor temperature is
below 5O°F (10 C). Refer to manufacturer's
recommendations. To avoid possible compressor
damage, allow the compressor to remain off for
five minutes before restarting
1. Slide the SYSTEM switch to Cool and the FAN
switch to Auto
g. Press the • key to lower the temperature setting
several degrees below the room temperature After
approximately five minutes, the cooling equipment
should start The fan starts and stops with the cool-
ing equipment
3. Press the • key to raise the temperature setting
above the room temperature Cooling system
should shut down.
NOTE: To bypass the 5 minute delay, see the Optional
System Checkout section
Fan
1. Slide the SYSTEM switch to Off and the FAN
switch to On. The fan should run continuously
g. Slide the FAN switch to Auto in heating, the fan is
controlled directly by the heating equipment and
may start a few minutes after the heating equip-
ment turns on (on most systems) When using an
electric heat thermostat, the fan starts and stops
with the heating equipment In cooling, the fan
starts and stops with the cooling equipment
Make certain all equipment responds properly to the
thermostat
5 69-1485-1

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