T498A,B
Electric Heat Thermostats
PRODUCT DATA
FEATURES
•
CSA Performance Certifled at 16A.
•
CSA Certified, Underwriters Laboratories Inc. Listed
up to 5 kW at 277 Vac.
•
•
Long life, industrial-grade Micro Switch™ mechanism.
Rugged, engineering plastic mounting base with
captive mounting screws.
•
Replaces any standard wall-mounted electric heat
thermostat.
•
•
•
•
Classic beige styling.
Range: 40°F to 80°F (5°C to 25°C).
Locking cover and range stops are optional.
Energy efficient and economical.
GENERAL
The T498A,B Electric Heat Thermostats provide line voltage
control of electric heating equipment. A snap action switch
makes heating circuit on temperature fall.
Contents
General ...............................................................................1
Features ..............................................................................1
Specifications ...................................................................... 2
Ordering Information ........................................................... 2
Installation ...........................................................................3
Setting and Checkout .......................................................... 4
Security Features ................................................................ 4
Calibration ...........................................................................5
Copyright © 1996 Honeywell Inc.
•
•
All Rights Reserved
95C-10686-3
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T498A,B ELECTRIC HEAT THERMOSTATS
1-1/4
(33)
ᕡ Leave the cover on the thermostat while making
connections.
ᕢ Push the leadwires into the outlet box and insert the
thermostat into the box for mounting by pushing against
the cover.
1-1/32
(26)
5/8 (16)
ᕣ Remove the thermostat cover by grasping the top and
bottom edges and pulling outward.
ᕤ Turn the dial so that the setpoint indicator is at the
12 o’clock position. This will prevent accidental damage
to the dial stop during mounting.
ᕥ Using a screwdriver, secure the thermostat to the outlet
box by tightening the two mounting screws. Handle the
thermostat with care; excessive pressure can damage
the control knob or sensing element.
OFF
3-9/32
(83)
2-3/32
(53)
4-17/32
(116)
1/2 (13)
M6089A
CAUTION
15/16
(24)
2-29/32 (72)
1. Disconnect power supply before making wiring
connections to prevent electrical shock or
equipment damage.
Fig. 1. Nominal dimensions in in. (mm).
2. All wiring must comply with applicable codes and
ordinances.
RECYCLING NOTICE
3
Thermostats are designed to be used with a
separate limit control in the appliance.
If this control is replacing a control that contains
mercury in a sealed tube, do not place your old
control in the trash.
ᕦ Using wire connectors approved for No. 12 wires, make
line voltage wiring connections directly to the leadwires
installed on the thermostat.
Contact your local waste management authority for
instructions regarding recycling and the proper
disposal of any control containing mercury in a
sealed tube.
CAUTION
If connecting with aluminum conductors, use approved
CO/ALR solderless wire connectors to avoid fire
hazard.
INSTALLATION
L2
2
T498A
1
WARNING
ELECTRICAL SHOCK HAZARD.
3
L1
L1
HIGH VOLTAGE CONTROL.
(HOT)
This thermostat is a line voltage (120 to 277 volt)
control. Do not install this thermostat if you are not
completely familiar and competent with electrical
wiring. If improperly handled, there can be risk of 120
to 277 volt electric shock hazard that can cause
serious injury or death.
T1
4
ELECTRIC
HEATER
Location
Install a vertical outlet box that is used to mount the T498, four
to five feet (1.5m) above the floor on an inside wall where the
thermostat will be subjected to average room temperature.
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
1
2
USE SPECIAL SERVICE CO/ALR SOLDERLESS CONNECTORS
WHEN CONNECTING ALUMINUM CONDUCTORS OR A FIRE
HAZARD MAY RESULT.
Mount the thermostat away from concealed warm or cold water
pipes, warm air ducts, light switches and dimmers, refrigerators
or drafts from hallways, fireplaces, stairways or fans.
3
4
BREAKS AND REMAKES BELOW -31°F(-35°C); NORMALLY
THERMALLY ACTIVATED. BREAKS ON A TEMPERATURE RISE;
MAKES ON A TEMPERATURE FALL.
Mounting and Wiring
USE A SEPARATE LIMIT CONTROL IN THE HEATING APPLIANCE.
M6091A
When replacing an old line voltage electric heating
thermostat, remove the old thermostat carefully to avoid
damaging the insulation on the wiring.
Fig. 2.Typical hookup for T498A Thermostat.
Check the old insulation for cracks, nicks, or fraying and apply
approved electrical tape where necessary to achieve adequate
insulation, or replace the wires using approved methods.
3
95C-10686—3
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T498A,B ELECTRIC HEAT THERMOSTATS
L2
2
T498B
1
6
3
L1
L2
T2
L1
(HOT)
RED WIRE
5
T1
6
0
0
5
4
7
0
0
4
ELECTRIC
HEATER
OFF
8
0
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
1
2
USE SPECIAL SERVICE CO/ALR SOLDERLESS CONNECTORS
WHEN CONNECTING ALUMINUM CONDUCTORS OR A FIRE
HAZARD MAY RESULT.
°F
BREAKS AND REMAKES BELOW -31°F(-35°C); NORMALLY
THERMALLY ACTIVATED. BREAKS ON A TEMPERATURE RISE;
MAKES ON A TEMPERATURE FALL.
3
50 60 70 80 90
4
5
6
USE A SEPARATE LIMIT CONTROL IN THE HEATING APPLIANCE.
BREAKS AT POSITIVE OFF ONLY; NOT THERMALLY ACTIVATED.
DO NOT CONNECT GROUNDED CONDUCTORS (NEUTRAL) ON
120V OR 277V CIRCUITS. INSULATE AND TAPE, OR CUT OFF
RED WIRES IF UNUSED.
M6092A
M7236
Fig. 3.Typical hookup for T498B Thermostat.
Fig. 4. Locking cover installation.
SETTING AND CHECKOUT
IMPORTANT
Range Stops
Make sure all wiring connections are tight.
ᕡ Set the thermostat to the desired setpoint. Remove the
cover.
After the thermostat has been installed and wired, simulate
normal operation as follows.
ᕡ Turn the setting dial completely clockwise. The electric
heater should start to heat.
ᕢ Turn the dial completely counterclockwise. The power
circuit should be broken and the electric heater should
start to cool.
ᕢ Install the plastic dowels (included) into the minimum
and/or maximum range stop holes on the inside back of
the cover. See Fig. 5.
ᕣ Replace the cover. Check the operation of the range
stops.
ᕣ To determine the final setting, move the dial indicator to
the 70°F (21°C) position on the scale. If the setting is
not satisfactory after a minimum of two hours of
thermostat operation, turn the dial indicator to raise or
lower the temperature. Move the indicator only a few
degrees each time an adjustment is necessary.
RANGE STOP
HOLES
SECURITY FEATURES
Locking Cover
ᕡ Remove cover by swinging up from the bottom edge of
the thermostat.
ᕢ Insert the Tinnerman Speed Nut® (included) into the
slot on the lower back of thermostat base. See Fig. 4.
ᕣ Insert the Allen screw into the Speed Nut until the
screw head is flush with the lower edge of the
thermostat base.
ᕤ Replace the thermostat cover and lock by removing the
Allen screw until screw body protrudes through the
cover hole.
M7238
ᕥ To unlock the cover, insert the Allen screw into the
thermostat base until the screw body clears the cover.
Fig. 5. Range stop installation.
95C-10686—3
4
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T498A,B ELECTRIC HEAT THERMOSTATS
CALIBRATION
The T498 Thermostats are calibrated at the factory using
precise instruments under closely controlled conditions.
Recalibration should not be necessary. Allow the thermostat
to operate for several hours before checking calibration.
Temperature deviations of 2°F (1°C) are normal. If the
thermostat is mounted in a suitable location and still appears
out of calibration, check calibration using the procedures that
follow.
6
0
0
5
7
0
8
0
Check Calibration
ᕡ Remove the thermostat cover and set it aside for
several minutes. Radiant heat from your hands will
affect the thermometer reading.
ᕢ Turn the setting dial clockwise until the switch makes
(clicking sound) and the heating equipment and fan
start.
°F
50 60 70 80 90
ᕣ No recalibration is necessary if the thermostat switch
makes with the thermostat setting at the same
temperature as indicated on the thermostat cover
thermometer.
ᕤ If the thermostat setting differs from the thermometer,
record the temperature difference and recalibrate as
instructed in the Recalibration Procedure section.
APPLY NEW INSERT DECAL
M7237
Fig. 6.Thermostat recalibration.
Recalibration Procedure
ᕡ Note the temperature difference between the
thermostat setting and the thermometer.
ᕢ Turn the setting dial clockwise until the switch makes
(clicking sound).
ᕣ Remove the adhesive backing of the indicator decal
provided.
ᕤ Carefully align the indicator mark on the decal with the
correct temperature setting number on the cover. See
Fig. 6.
ᕥ Using finger pressure, secure the realigned decal on
the center of the knob.
ᕦ Wait five minutes and recheck the calibration.
5
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7
95C-10686—3
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Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Honeywell Limited-Honeywell Limitée
35 Dynamic Drive
Golden Valley, Minnesota 55422
Scarborough, Ontario M1V 4Z9
95C-10686—3 C.H. Rev. 4-96
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