Honeywell T834C User manual

Honeywell
T834B; T834C; T834J
Heating-Cooling Thermostats
INSTALLATION INST UCTIONS
APPLICATION
The T834B,C,J Heating-Cooling Thermostats provide 24
to 30 Va ontrol in heating- ooling systems. An spdt
mer ury swit h makes R to W on a temperature fall for
heating, and R to Y on a temperature rise for ooling.
Integral swit hes ontrol HeAt-OFF-COOL or COOL-OFF
system operation and AUTO-ON or ON-AUTO fan
operation (fan swit h on T834C,J only). In heat pump and
some ele tri heat systems, fan operation is ontrolled by
the thermostat during heating. Che k the ele tri heat
manufa turer spe ifi ations for fan ontrol requirements. If
fan ontrol from the thermostat is ne essary in an ele tri
heat appli ation, use the T834C Thermostat model (dual
fuel) with optional fan ontrol. Jumper terminals 1 and 2 to
ontrol fan operation from the thermostat during heating.
TERMINALS 1 AND 2 FOR AUTOMATIC FAN CONTROL IN HEATING
AND COOLING.
A IN GAS-AND OIL-FIRED APPLICATIONS, JUMPER TERMINALS 1
AND Y FOR AUTOMATIC FAN CONTROL IN COOLING. M8675
Fig. 1. Jumpering terminals for fan control.
® ECYCLING NOTICE
This ontrol ontains mer ury in a sealed tube.
Do not pla e ontrol in the trash at the end of
its useful life.
If this ontrol is repla ing a ontrol that ontains
mer ury in a sealed tube, do not pla e your old
ontrol in the trash.
Conta t your lo al waste management authority
for instru tions regarding re y ling and the proper
disposal of this ontrol, or of an old ontrol
ontaining mer ury in a sealed tube.
INSTALLATION
When Installing this Product...
1. Read these instru tions arefully. Failure to follow
them ould damage the produ t or ause a hazard
ous ondition.
2. Che k the ratings given in the instru tions and on
the produ t to make sure the produ t is suitable for
your appli ation.
3. Installer must be a trained, experien ed servi e
te hni ian.
4. After installation is omplete, he k out produ t
operation as provided in these instru tions.
A CAUTION
Damage to Heating/Cooling System Possible.
Be careful when handling wires during
installation.
Dis onne t power at furna e or at main breaker/
fuse before starting installation.
Location
Lo ate the thermostat about 5 ft (1.5m) above the floor on
an inside wall in an area with good air ir ulation at
average temperature.
Do not mount the thermostat where it may be affe ted by:
— drafts or dead spots behind doors or in orners.
— hot or old air from du ts.
— radiant heat from the sun, firepla es, or applian es.
®U.S. Registered Trademark
Copyright © 1999 Honeywell In . All Rights Reserved 69-0444-10

T834B; T834C; T834J HEATING-COOLING THERMOSTATS
Wiring and Mounting
Dis onne t power supply before beginning installation to
prevent ele tri al sho k or equipment damage.
All wiring must omply with lo al odes and ordinan es.
The T834 may be mounted dire tly on a wall or verti al
outlet box. Use Honeywell part no. 193121A Mounting
Plate Assembly (ordered separately) to mount on horizon
tal outlet box or over marks left by old thermostat. If
mounting plate assembly is used, review instru tions
provided with assembly before wiring and mounting
thermostat.
To wire and mount thermostat:
1. In repla ement appli ations, he k the existing
thermostat wires for ra ked or frayed insulation.
Repla e any wires in poor ondition. If the wire is
plastered into the wall, make a hole next to the
wires and loosen the wires so they an be
pushed ba k into the wall later.
2. In new installations, run wiring (if ne essary) to the
thermostat lo ation.
3. Conne t the wires to the terminals on the ba k of
the thermostat. See Fig. 3 through 12 for
internal s hemati and typi al hookup diagrams.
If ontrol of fan operation from the thermostat is
required in a entral ele tri heat appli ation,
jumper terminals 1 and 2. See Fig. 1.
4. Remove thermostat over by pulling outward on
bottom edge of the over until it snaps free of the
thermostat base. See Fig. 2. Carefully remove
and dis ard the foam plasti shipping insert that
prote ts the swit h and bimetal assembly during
shipping.
5. Set the adjustable heat anti ipator indi ator to
mat h the urrent draw of the primary heating
ontrol (see Heat Anti ipator Setting se tion).
6. Push ex ess wire ba k through the hole and plug
any opening with insulation to prevent drafts that
may affe t thermostat performan e.
7. Loosely fasten the thermostat to the wall or outlet
box with a s rew through the top mounting hole.
Adjust the thermostat so that it is approximately
level and start the se ond s rew through the
bottom mounting hole. Do not tighten.
8. Level the thermostat exa tly using a spirit level or
plumb line. Tighten the mounting s rews.
IMPORTANT
An incorrectl leveled thermostat will cause the
temperature control to deviate from setpoint.
9. Repla e the thermostat over.
FAN
SWITCH
A
AFAN SWITCH AVAILABLE ON T834C ONLY. M8676
Fig. 2. Internal view of T834.
FAN SWITCH
> ANTICIPATOR
k ______
ON
AUTO
C1
FALL
)
H1
ANTICIPATOR *
»WITCH
COOL HEAT
/ !
OFF OFF
—
HEAT COOL
A
R
FAN RELAY
<D— H v T - M
a
HEAT RELAY
— K v 4 -
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
L1
(HOT)
L2
A
H1
Fig. 3. Internal sche atic and typical hookup diagra for T834C in standard heating-cooling syste .
69-0444— 10 2

T834B; T834C; T834J HEATING-COOLING THERMOSTATS
A IN ELECTRIC HEAT APPLICATION, JUMPER 1 AND 2 FOR AUTO FAN IN HEATING. M2035A
Fig. 4. Internal sche atic and typical hookup for T834C dual fuel odel
in a gas- or oil-fired, or central electric heat syste .
JUMPER W-Y FOR SINGLE-STAGE HEAT PUMP.
Fig. 6. Internal sche atic and typical hookup for T834C gas or oil-fired syste s and single-stage
heat pu p or central electric heat.
3 69-0444— 10

T834B; T834C; T834J HEATING-COOLING THERMOSTATS
H1
Fig. 8. Internal sche atic and typical hookup for T834C with ter inal for defrost relay in heat pu p syste .
FAN
69-0444— 10 4

T834B; T834C; T834J HEATING-COOLING THERMOSTATS
Fig. 10. Internal sche atic and typical hookup for T834B in standard heating-cooling syste
with no fan switching.
H1
A
Fig. 11. Internal sche atic and typical hookup for T834B in heating-cooling syste with zone valve.
Fig. 12. Internal sche atic and typical hookup for T834J cooling only syste .
5 69-0444— 10

T834B; T834C; T834J HEATING-COOLING THERMOSTATS
SETTINGS AND ADJUSTMENT
System and Fan Switching
T834B
The T834B features a SYSTEM swit h for ontrol of the
heating- ooling system.
The SYSTEM swit h ontrols system operation as follows:
HEAT: Heating system only operates.
OFF: Both heating and ooling ontrol systems are
dis onne ted.
COOL: Cooling system only operates.
The fan operates in response to the plenum fan ontrol in
heating; fan operates with ooling equipment in ooling.
T834C
The T834C features SYSTEM and FAN swit hes for
ontrol of the heating- ooling and fan systems.
The SYSTEM swit h ontrols system operation as follows:
HEAT: Heating system only operates.
OFF: Both heating and ooling ontrol systems are
dis onne ted.
COOL: Cooling system only operates.
The FAN swit h ontrols fan operation as follows:
AUTO: for onventional (gas, oil or entral ele tri heat)
systems, the fan operates in response to the plenum
fan ontrol in heating; fan operates in response to
the thermostat in ooling. For heat pump systems,
the fan operates in response to the thermostat in
both heating and ooling.
ON: The fan runs ontinuously.
T834J
The T834J features SYSTEM and FAN swit hes for
ontrol of the ooling and fan systems.
The SYSTEM swit h ontrols system operation as follows:
OFF: Cooling ontrol system is dis onne ted.
COOL: Cooling system operates.
The FAN swit h ontrols fan operation as follows:
AUTO: Fan operates in response to the thermostat in
ooling.
ON: Fan runs ontinuously.
NOTE: Some ele tri heat systems require ontrol of fan
operation from the thermostat. These systems
require a thermostat with ontrol of fan operation
in response to a all for heating or ooling.
To swit h positions, use thumb and index finger to slide
lever to desired position. Swit h lever must stop dire tly
over desired fun tion indi ator mark for proper ir uit
operation.
Temperature Setting
Push the temperature setting lever to the desired ontrol
point on the temperature s ale. The same lever ontrols
both heating and ooling. On models with temperature
range stops, temperature setting lever an be moved only
between the two temperature range stops.
HEAT ANTICIPATO SETTING
IMPORTANT
The T834 Thermostat has an adjustable heat
anticipator and will operate properl ONLY IF
THE ANTICIPATOR IS ADJUSTED TO MATCH
THE CURRENT DRAW OF THE PRIMARY
CONTROL. Use this thermostat onl on s stems
with current draws that fall within the range of the
heat anticipator. Do not use this device on
Powerpile® (millivolt) S stems.
Conventional Systems
A urrent rating is usually stamped on the nameplate of
the primary ontrol. Set the adjustable heat anti ipator
indi ator to mat h the value given on the nameplate.
If the urrent rating is not available, pro eed as follows to
determine the rating:
1. Turn off power.
2. Wire thermostat, ex ept for onne tion to
W terminal, but do not mount it on the wall.
3. Conne t ammeter between W wire and
W terminal on the thermostat.
4. Prepare the system for operation.
5. Turn on power.
6. Turn system swit h to heat.
7. In rease thermostat setpoint as ne essary to get
system operating.
8. With the system operating through the ammeter,
wait one minute, then read the ammeter.
9. Turn the system swit h to OFF, and turn off
power.
10. Adjust the heat anti ipator to mat h the reading
on the ammeter.
11. Dis onne t the ammeter, re onne t the W wire,
and mount the thermostat. Continue with system
he kout.
NOTE: The heat anti ipator may require further adjust
ment for best performan e. To lengthen burner-
on time, move the indi ator in the dire tion of the
longer arrows but not more than one-half s ale
marking at a time. To shorten burner-on time,
move indi ator in opposite dire tion.
Heat Pump Systems
(for about 3 cycles per hour)
Using B Terminal
Set adjustable anti ipator to 130 per ent of ombined
urrent draw of ompressor and fan relays.
Using O Terminal
Set adjustable anti ipator to maximum s ale setting. Limit
ombined load urrent of ompressor and fan relays to
0.8 amp, be ause ooling anti ipator provides anti ipation
during heat y le in these hookups.
69-0444— 10 6

T834B; T834C; T834J HEATING-COOLING THERMOSTATS
Electric Systems (with auto fan in heat)
Set adjustable anti ipator to ombined urrent draw of
heating and fan relays.
Other Systems (without auto fan in heat)
Set adjustable anti ipator to urrent draw of heat relay
or valve.
CHECKOUT
A CAUTION
Da age To Heat Anticipator Possible.
Shorting across ter inals of syste controls
ay cause da age to the heat anticipator.
Do not he k operation by shorting a ross
terminals of systems ontrols.
IMPORTANT
To assure accurate temperature control, do not
touch or breathe on bimetal or thermometer.
Heating
With system swit h set at HEAT and fan swit h, if appli
able, at AUTO, move the temperature setting lever about
10°F (6°C) above room temperature.
Conventional (gas, oil or entral ele tri heat) systems:
heating should start and fan should start after a
short delay.
Heat pump systems: both heating and fan should start.
Move temperature setting lever 10°F (6°C) below room
temperature.
Conventional systems: heating should shut off and fan
should shut off after a short delay.
Heat pump systems: heating and fan should shut off.
NOTE: Some ele tri heat systems require ontrol of fan
operation from the thermostat. These systems
require a thermostat with ontrol of fan operation
in response to a all for heating or ooling.
Cooling
A CAUTION
Da age to Co pressor Possible.
Operating at too low of an outdoor te perature
ay cause co pressor da age.
Do not operate ooling if outdoor temperature is
below 50°F (10°C). Refer to manufa turer re om
mendations.
NOTE: To prevent ompressor short y ling, a minimum
off-timer may be in luded to provide a five-minute
time delay before a tivating the ompressor after
the thermostat last turned off the ompressor, or
after the system first re eived power. This delay
prote ts the ompressor.
With the system swit h set at COOL and fan swit h, if
appli able, at AUTO, move the temperature setting lever
about 10°F (6°C) below room temperature. Cooling and
fan should start (see NOTE above). Move the temperature
setting lever about 10°F (6°C) above room temperature.
Cooling and fan should shut off.
Fan
T834B
Fan operates with the ooling equipment in ooling; fan
operates in response to the plenum fan ontrol in heating.
T834C
With the system swit h set at OFF, and the fan swit h at
ON, the fan should run ontinuously. Move the fan swit h
to AUTO. In onventional systems, fan operation is
ontrolled by the thermostat in ooling and by the plenum
fan ontrol in heating. In heat pump systems, fan operation
is ontrolled by the thermostat in both heating and ooling.
T834J
With the system swit h set at OFF, and the fan swit h
at ON, the fan should run ontinuously. Move the fan
swit h to AUTO. The fan operation is ontrolled by the
thermostat.
7 69-0444— 10

T834B; T834C; T834J HEATING-COOLING THERMOSTATS
ECALIB ATION
These thermostats are alibrated at the fa tory and should
not need re alibration. If the thermostat seems out of
adjustment, first he k for a urate leveling. To he k
alibration, pro eed as follows:
1. Move the temperature setting lever to the left
(low) end of the temperature s ale. Pla e system
swit h at OFF. Wait at least five minutes.
2. Remove the thermostat over. Move the setting
lever until the swit h just makes onta t. The
mer ury in the swit h will roll to the left end of
the tube.
3. Repla e over and wait five minutes for the over
and the thermostat to lose the heat it has gained
from your hands. If the thermometer pointer and
the setting lever indi ator read approximately the
same, no re alibration is needed.
3. Move the setting lever to a low setting. Wait at
least five minutes for temperature to stabilize.
4. Slowly move the setting lever until it reads the
same as the thermometer.
5. Remove over. Holding the setting lever so it
does not move, reinsert wren h and arefully turn
ounter lo kwise \ until the mer ury rolls to
the left end of the tube but no farther.
6. Re he k alibration. Set thermostat system
swit h for desired operation and repla e over.
COIL SHOWN WITHOUT
HEAT ANTICIPATOR
If re alibration appears ne essary, pro eed as follows:
1. Pla e the temperature setting lever at the same
setting as the thermometer. Remove over.
2. Insert Honeywell part no. 104994A Calibration
Wren h (order separately) onto the hex nut under
the oil. See Fig. 13. Holding the setting lever so
it does not move, turn the wren h lo kwise
until the mer ury rolls to the right end of the tube.
Remove wren h and repla e over.
To ensure a urate temperature ontrol, do not
tou h or breathe on bimetal or thermometer.
Æ 2
CALIBRATION
WRENCH M2044A
Fig. 13. Recalibration procedure.
Honeywell
Automation and Control Solutions
Honeywell International Inc. Honeywell Li ited—Honeywell Li itée
1985 Douglas Drive North 35 Dyna ic Drive
Golden Valley, MN 55422 Scarborough, Ontario M1V 4Z9
69-0444—10 G.H. Rev. 5-99 ® Printed in U.S.A. on re y led
paper ontaining at least 10%
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