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T4398A,B PRECISION ELECTRIC HEATING THERMOSTAT

5

69-1604

OPERATION AND CHECKOUT

After the thermostat is installed and wired, check out normal 
operation as follows:

1.

Turn setting dial fully clockwise until the switch clicks 
and the electric heater starts to heat.

2.

Turn the dial fully counterclockwise; the power circuit 

breaks and the electric heater starts to cool.

3.

The T4398 is a more accurate thermostat, allowing 

users to be more comfortable at lower setpoint settings 

(saving energy and lowering heating costs). To deter-
mine final setting:

a. Begin with setting the dial indicator at 68°F (20°C).

b. After two operating hours, if not comfortable, adjust 

setpoint to raise or lower the temperature, adjusting 

temperature only a few degrees each time.

Calibration

IMPORTANT

Do not assume the thermostat is out of calibration 

until it is installed and allowed to operate for several 
hours.

The T4398 is accurately calibrated at the factory under 
controlled conditions. The snap switch turns on heat when the 

setpoint is raised to room temperature. 

The vapor-filled diaphragm sensor is affected by barometric 

pressure and altitude. Deviations up to 1°F (±1/2°C) are within 

normal operation. The control point drops 2°F every 1000 ft 
(1°C/300m) above sea level. See Fig. 5 and 6.

Fig. 5. T4398 altitude correction in (ft). 

Fig. 6. T4398 altitude correction in (m).

To calibrate (see Fig. 7):

1.

Remove cover and place it in a location that allows it to 
sense the room temperature. 

NOTE: Allow several minutes for the thermometer to stop 

being affected by the heat from your hand.

2.

Rotate the setpoint knob counterclockwise until you 
hear the switch click.

3.

Hold the setpoint knob firmly and rotate the setpoint 

scale ring counterclockwise until 12 o’clock on the ring 
is aligned with the thermometer cover.

4.

The heat from your hand will affect the diaphragm sen-

sor so wait five minutes and verify the calibration.

10

8

6

0

1000

F

2000

ELEVATION IN FEET

SEA

LEVEL

3000

4000

5000

6000

4

2

0

LOS ANGELES

ATLANTA

LAS VEGAS

DENVER

M20353

101

99

95

93

89

0.4

KPa

ELEVATION

CITIES WITH

TEMPERATURE

CORRECTIONS

(  C CORRECTIONS

TO BE ADDED)

INCREASING

B

A

R

OMETRIC PRESSURE

ELEVATION IN METERS

1.2 2.0 2.8 3.6 4.4 5.2 6.0

M20354

(SEA LEVEL)

WINNIPEG

CALGARY

0   

240M

574M

677M

1079M

(FOR EXAMPLE, A 
CORRECTION OF
APPROXIMATELY 3.5  C 
WOULD BE INDICATED 
FOR INSTALLATION
IN CALGARY.)

REGINA

EDMONTON

Summary of Contents for T4398A

Page 1: ...lement provides high temperature sensitivity with minimum droop Canadian Standards Association CSA Performance Certified up to 20A CSA Certified UL Listed up to 5 kW at 277 Vac Long life industrial grade Micro Switch mechanism Rugged engineered plastic mounting base with captive mounting screw Color coded flyleads compatible with aluminum wire for quick installation Replaces any standard wall moun...

Page 2: ...nd thermal non adjust able Switch Type Enclosed industrial grade Micro Switch snap switch T4398A Single line break single pole single throw T4398B Double pole single throw with double line break double pole single throw in Off position Wiring Connections Six inch 150 mm stranded copper leadwires suitable for con necting to aluminum wiring if approved special service CO ALR connectors are used Elec...

Page 3: ...n old line voltage thermostat Carefully remove the old thermostat to avoid damaging the wiring insulation Check the old insulation for cracks chips or fraying and apply approved electrical tape where necessary to ensure adequate insulation NOTE Make line voltage wiring connections directly to the leadwires installed on the thermostat using wire con nectors approved for the number and size of condu...

Page 4: ...R 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...

Page 5: ...r is affected by barometric pressure and altitude Deviations up to 1 F 1 2 C are within normal operation The control point drops 2 F every 1000 ft 1 C 300m above sea level See Fig 5 and 6 Fig 5 T4398 altitude correction in ft Fig 6 T4398 altitude correction in m To calibrate see Fig 7 1 Remove cover and place it in a location that allows it to sense the room temperature NOTE Allow several minutes ...

Page 6: ...lock cover drive Allen screw into thermostat base until screw body clears cover Fig 8 Installing locking cover To install the range stops select models Fig 9 1 Set thermostat to desired setpoint and remove the cover 2 Install plastic dowels supplied into minimum and or maximum range stop holes on the back of the cover 3 Reinstall the cover and check range stop operation Fig 9 Installing range stop...

Page 7: ... the diaphragm changes into liquid The diaphragm collapse to a fraction its original thickness turning on the heat regardless of setpoint This feature guarantees minimum yet reliable operation of heaters in spaces near freezing NOTE To prevent heat from turning on below 40 F 4 C turn off the circuit at the breaker panel or install a T4398B ...

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