T4398A,B HIGH PERFORMANCE ELECTRIC HEAT THERMOSTATS
68-0147—2 4
WALL
MOUNTING
SCREWS (2)
M5797
OUTLET
BOX
THERMOSTAT
BASE
8
0
7
5
7
0
6
5
6
0
5
5
5
0
SETTING DIAL
INDICATOR
M5791B
L1
(HOT)
L2
L1
T1
1
2
4
3
SOLDERLESS
CONNECTORS
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
USE SPECIAL SERVICE CO/ALR SOLDERLESS CONNECTORS
WHEN CONNECTING ALUMINUM CONDUCTORS OR A FIRE
HAZARD MAY RESULT.
USE A SEPARATE LIMIT CONTROL IN THE HEATING APPLIANCE.
BREAKS AND REMAKES BELOW -31°F (-35°C); NORMALLY
THERMAL ACTIVATED. BREAKS ON TEMPERATURE RISE;
MAKES ON TEMPERATURE FALL.
1
2
3
4
T4398A
ELECTRIC
HEATER
Fig. 2. Typical wiring connections for T4398A.
Fig. 3. Typical wiring connections for T4398B.
M5792B
L1
(HOT)
L2
L1
T1
1
2
4
SOLDERLESS
CONNECTORS
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
USE SPECIAL SERVICE CO/ALR SOLDERLESS CONNECTORS
WHEN CONNECTING ALUMINUM CONDUCTORS OR A FIRE
HAZARD MAY RESULT.
BREAKS AT POSITIVE OFF AND REMAKES UNDER –31°F (–35°C);
NORMALLY THERMALLY ACTIVATED. BREAKS ON TEMPERATURE
RISE; MAKES ON TEMPERATURE FALL.
USE A SEPARATE LIMIT CONTROL IN THE HEATING APPLIANCE.
BREAKS AT POSITIVE OFF ONLY; NOT THERMALLY ACTIVATED.
DO NOT CONNECT GROUNDED CONDUCTOR (NEUTRAL) ON
120 OR 227V CIRCUITS. INSULATE AND TAPE OR CUT OFF
RED WIRES IF UNUSED.
1
2
3
4
5
6
5
L2
T2
3
ELECTRIC
HEATER
RED
WIRE
6
T4398B
Fig. 4. Mounting thermostat to outlet box.

New Applications

Disconnect power supply to prevent electrical shock or
equipment damage. All wiring must comply with local
electrical codes and ordinances.
Run line voltage wiring to the thermostat location.
Do not remove T4398 Thermostat Cover. Using wire
connectors approved for No. 12 wires, make line
voltage connections directly to leadwires on thermostat.
See Figs. 2 and 3 for typical wiring connections.
Prebend and push solid wires into the outlet box.
Remove the thermostat cover by grasping the top and
bottom edges and pulling outward away from the base.
Turn the setting dial so indicator is at the 12 o’clock
position to prevent damaging the sensing element when
mounting the thermostat.
Mount the thermostat on the outlet box as shown in
Fig. 4. Secure the thermostat by tightening the two
mounting screws.
SETTINGS AND ADJUSTMENTS

Calibration

The T4398 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. The
T4398 Thermostat vapor-filled dual diaphragm sensing
element is affected by barometric pressure and altitude.
Temperature deviations of 1°F (0.5°C) are normal. If the
thermostat is mounted in a suitable location (as instructed in
the Location section) and still appears out of calibration,
check calibration as follows.

Check Calibration

Remove the thermostat cover and set it aside for
several minutes because radiant heat from your hands
will affect the thermometer reading.
Turn the setting dial clockwise until the switch makes
(click sound). The heating equipment and fan start.
No recalibration is necessary if the thermostat switch
makes with the thermostat setting at the same
temperature as indicated on the thermostat cover
thermometer.