Larson Electronics EXP-TSTAT-125.250-60.250F-0.25-V1-15L User manual

EXP-TSTAT-125.250-60.250F-0.25-V1-15L
Explosion Proof Thermostat
Instruction Manual
Thank you for your purchase of the Larson Electronics EXP-TSTAT explosion proof thermostat.
WARNING
TO AVOID THE RISK OFFIRE, EXPLOSION OR ELECTRIC SHOCK, THIS PRODUCT SHOULD BE INSTALLED,
INSPECTED AND MAINTAINED BY A QUALIFIED ELECTRICIAN ONLY, IN ACCORDANCE WITH ALL
APPLICABLE ELECTRICAL CODES.
TO AVOID ELECTRIC SHOCK:
•BE CERTAIN ELECTRICAL POWER IS OFF BEFORE AND DURING INSTALLATION AND MAINTENANCE.
•PRODUCT MUST BE CONNECTEDTOA WIRING SYSTEM WITHAN EQUIPMENT-GROUNDING
CONDUCTOR.
TO AVOID EXPLOSION:
•MAKE SURE THE SUPPLY VOLTAGE IS WITHIN THE VOLTAGE RATING.
•ENSURE THE MARKED T RATING IS LESS THAN THE IGNITION TEMPERATURE OF THE HAZARDOUS
ATMOSPHERE.
•DO NOT OPERATE IN AMBIENT TEMPERATURES ABOVE THOSE INDICATED ON THE PRODUCT
NAMEPLATE.
•DO NOT OPERATE IF THE LENS, CORD, SEALS, HOUSING, RECEPTACLES, ETC. IS CRACKED OR
DAMAGED. IF SO, DISCONTINUE USE AND CONTACT MANUFACTURER FOR REPLACEMENT PARTS.
•ALL FASTENERS SHOULD BE PROPERLY SEATED.
The Larson Electronics EXP-TSTAT-125.250-60.250F-0.25-V1-15L Explosion Proof Thermostat is designed for
temperature applications in industrial facilities where flammable gases, vapors or dust are or may be present. This 30-amp
device operates on 120-250V AC and comes with an adjustable point knob system, which features a DPST switch. The unit
is equipped with a fifteen-foot cable.
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GENERAL
NOTICE: Type EXP-TSTAT controls are designed for
temperature control service only. Because they do not fail safe,
they should not be used for temperature limiting duty.
WARNING: Users should install adequate back-up
controls and safety devices with their electric
heating equipment. Where the consequences of
failure may be severe, back-up controls are essen-
tial. Although the safety of the installation is the
responsibility of the user, Larson Electronics will
be glad to make equipment recommendations.
Principle of Operation — Control action of these thermostats is
provided through the principle of liquid volume change. With a
variation in temperature, the liquid in the sensing bulb expands or
contracts, causing a bellows to actuate the switching mechanism.
Housing — The control housing and cover assembly is of heavy-
duty cast aluminum.
Control Range — The following temperature ranges are available:
Fahrenheit
0° to 100° 200° to 550°
60° to 250° 300° to 700°
Process Temperature Differential — is variation in controlled
process temperature between maximum, when thermostat turns
OFF and minimum, when thermostat turns ON. This spread in
temperature may be minimized by —
1. Making sure control is mounted to vertical surface. (See Step
1, MOUNTING section.)
2. Avoiding excess heating capacity (oversized heaters).
3. Locating control sensing bulb in optimum position between
heat source and work.
In general, it is difficult to predict the actual operating dif-
ferential of a given process. Temperature differential may be as
low as 4°F for low range controls to as high as 17°F for high-
er range controls since the differential is a percentage function
of the dial range.
Packing Glands — If a sealed or leak-proof connection is required
at the point where the capillary enters the oven, tank, pipe or simi-
lar equipment, an appropriate packing gland is available as an
optional part.

EXP-TSTAT-125.250-60.250F-0.25-V1-15L
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17
2 / "
32
Length
(Refer to Specifications —
Table A)
2"
Ca
O.D.
pillar
Typ.
y
21
2 / "
32
3
4 / "
32
9
2 / "
32
Dial
Stop
Post
Connect Load
Here
Shaft Shown
In "Off" Position
(Without Calibrated Cap)
Connect Power
Supply Here
11 16
/ " Calibration Cap
White Nylon
Universal Coupler
Set Screw Lock
Figure 1
61/2”
81/4”
41/4”4”

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EXP-TSTAT-125.250-60.250F-0.25-V1-15L
MOUNTING
Note: Do not mount thermostat where it will be subject to vibra-
tion, shock, grease, dust, lint or corrosive vapors. Do not mount
adjacent to a large magnetic contactor, as vibration and shock will
cause thermostat to interact erratically — resulting in chattering of
the contactor.
The air temperature in and around the thermostat enclosure
should be kept as near to normal room temperature as possible...
never above 150°F.
1. Thermostat must be mount-
ed in a vertical position only.
2. Use sheet metal or wood
screws through the two 5/16”
diameter mounting holes in
mounting lugs to mount
control (see Figure 2).
3. For controlling platen or die
temperatures, insert entire
sensing bulb into drilled holes
selected for snug slip fit.
The longer, more sensi-
tive Style 9 bulbs should be
used for controlling air tem-
peratures or pipe line heating.
4. NOTICE:
A. Bending or deforming
sensing bulb will alter
control calibration —
requiring recalibration after installation. See CALIBRA-
TION section. If necessary, Style 9 bulbs can be coiled
to 1” I.D. (see Figure 3).
B. Do not kink capillary tube. The resulting constrictions in
fluid flow can destroy control function or broaden temper-
ature differential. Minimum capillary tube bending diame-
ter is 1/2” I.D. (see Figure 4).
C. Any deformations of bulb or capillary that result in leakage
of fluid from control renders control inoperative.
D. Avoid passing control capillary tube through zones whose
temperature is in excess of controlled process temperature.
Erratic control or destruction of control function may result.
Mounting
Lugs
Capillary
Seal
Fitting
3"
3
7 / "
8
Figure 2
Figure 3
(Sensing Bulb)
Figure 4
(Capillary Tube)
Do Not
Bend or Kink
Crimped End
1/2”
Rod
1”
WIRING
WARNING: Hazard of Electric Shock. Disconnect all
power before wiring or servicing this control.
Failure to comply can result in electrical shock or
electrocution.
1. Electric wiring to heater must be installed in accordance with
National Electrical Codes and local codes. WARNING: Use
copper conductors only.
2. Entrance for wiring is provided by one 3/4” NPT hole in the top
of the housing. Wiring to control housing must be in rigid con-
duit also in accordance with National Electrical Codes (NEC)
for hazardous locations.
3. Set thermostat knob to OFF position and remove cover plate by
loosening and removing four (4) fastening screws (see Figure 5).
Figure 5

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EXP-TSTAT-125.250-60.250F-0.25-V1-15L
4. Remove white shaft coupler for safe-keeping while making
wiring connections (see Figure 6).
5. Connect wires according to wiring diagrams (Figures 7 thru 11).
Note: Electrical connections should be made with generous
loops of wire — approximately 6” per lead.
6. Replace white shaft coupler.
7. WARNING: It is possible to replace enclosure
cover with adjustment knob 180 rotational
degrees out of alignment resulting in large cali-
bration errors. To avoid this, carefully follow
these procedures.
A. Be sure that thermostat shaft is fully counter-clockwise (see
Figure 12). With thermostat knob held in the indicated OFF
position, carefully replace enclosure cover while feeling for
proper engagement of
shaft coupling.
B. With cover screws replaced
and moderately fastened,
check for full rotation of
dial knob. Note: Mild shaft
resistance should be
encountered. If satisfied,
that proper engagement of
shaft coupler is accom-
plished; finish tightening
cover screws.
8. Note: If load amperage or
voltage rating exceeds switch
rating, a contactor must be
used. Contactor and wiring to
be supplied by customer (see
WIRING
Dial
Stop
Post
Stop
Tab
Figure 12
Figure 6
1
2
3
4
1
2
3
4
Pilot
Light
Load
Line
Single Phase
Pilot Light
Load
Line
Single Phase
1
2
3
4
Pilot Light
Line
Load
Load
Two Circuit
1
2
3
4
1
2
3
4
Pilot
Light
Line
Three Phase
when Load
Does Not
Exceed
Rating of
Thermostat
}
Three Phase
and Single
Phase when
Load Exceeds
Rating of
Thermostat
Control
Voltage
Line
Load
Pilot
Light
Contactor
Figure 7 Figure 8 Figure 9
Figure 10 Figure 11

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EXP-TSTAT-125.250-60.250F-0.25-V1-15L
CALIBRATION
WARNING: Hazard of Electric Shock. Extreme care
should be exercised during calibration adjustments
because of shock hazard due to exposed electrical
terminals. Failure to comply can result in electrical
shock or electrocution.
These controls are factory calibrated to the range indicated on
the control adjustment knob.
If calibration is required, either one of two methods may be
followed.
1.
2.
If accurate measurement standards are not available, the ther-
mostat can readily be adjusted to a known temperature standard
such as boiling water (212°). See Figure 13.
With the aid of an accurate thermometer or other temperature
measuring device, recalibration may be performed within the
process as in Figure 14.
For either method, the following general calibration procedures
should be followed.
Figure 13
CALIBRATION
DANGER: Calibration will involve exposure of inter-
nal control terminals to ambient conditions during
some part of the recalibration procedure.
Combustible materials which cause hazardous
conditions must not be present during recalibra-
tion process — otherwise explosion may result.
1.
2.
Heat water bath or the equipment in which the control is
installed (tank, die, platen or machine) to the selected calibra-
tion temperature. The entire sensing bulb and at least one foot
of its capillary tube are to be exposed to calibrating tempera-
ture. With thermostat energized, allow process or bath to reach
setpoint. This is accomplished when thermostat begins cycling
action.
Compare adjustment knob cut off temperature indication
against actual temperature to which sensing bulb is exposed.
Figure 15 shows example of a control knob showing a control
indication of 250°F when true process temperature measured
230°F. In this example, the control knob must be rotated 20°
counterclockwise to bring the 230°F knob marking under the
index mark in order to recalibrate the control.
3. Without disturbing the shaft setting, loosen the thermostat
knob set-screw and re-align dial setting accordingly. Retighten
knob set-screw.
4. Recheck for thermostat operation as per steps 2 and 3 and make
further calibration adjustment if indicated.
5. Recheck of thermostat operation following final adjustment
completes the calibration procedure.
IMPORTANT: Under no circumstances must the temperature
range, and in particular, the maximum temperature setting of con-
trol be increased above maximum temperature indicated on control
nameplate. Such changes voids U.L. listing of the control.
Thermometer
Load (Tank, vat, die or platen)
Indicated Temp. True Temp
250
200
A
Figure 14
Figure 15

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EXP-TSTAT-125.250-60.250F-0.25-V1-15L
THERMOSTAT SUB ASSEMBLY REPLACEMENT
1. Before removing enclosure cover, turn thermostat knob to the
OFF position (counterclockwise). Place a piece of masking
tape over the knob to keep it in the OFF position.
2. Remove the enclosure cover by removing four fastening
screws (Figure 5).
3. Remove the white shaft coupler for safe-keeping.
4. Remove the thermostat mounting screws (2).
5. Loosen the capillary-seal retaining cap set screws and then
remove the retaining cap.
Note: Do not remove the entire capillary seal fitting from the
enclosure.
6. Remove the capillary seals and thermostat from the enclosure.
7. Remove the calibration cap (Figure 1) and insert pin from the
old thermostat. Rotate the position of the calibration cap, for
use in the next step.
8. With replacement thermostat in the OFF position (shaft complete-
ly counterclockwise), install insert pin and calibration cap. Install
calibration cap with same orientation as noted in step 7 above.
9. If excess capillary, on old thermostat, had been coiled in enclo-
sure, it may be necessary to coil an equal amount on replace-
ment thermostat per step 4D mounting instructions.
10. After proper capillary length is obtained on replacement ther-
mostat, insert capillary in the enclosure and thru the capillary
seal fitting.
11. Recheck for proper capillary length (external to enclosure) and
adjust if necessary.
12. Align spacer plate and replacement thermostat to mounting
holes in the bottom of enclosure using mounting screws (2 –
#10-32 x 3/8 Lg.) to secure thermostat to enclosure.
13. Slide the capillary seals into the capillary fitting making sure
the capillary is positioned in the center groove of the seals.
WARNING: If capillary is not located in the cen-
ter groove properly, damage to the capillary will
result, rendering the thermostat inoperable or
unreliable.
14. Replace capillary seal retaining cap and tighten set screws to
lock in position.
Note: Per the NEC, all threaded connections in a hazardous
environment must be tightened sufficiently to engage five full
threads.
15. Rewire replacement thermostat per appropriate wiring dia-
grams (Figures 7 thru 11).
16. Replace the white nylon coupling on the calibration cap and
enclosure cover per step 7 of the wiring section.
17. Replacement thermostat control should be monitored to insure
proper operation. If calibration is required, see the calibration
section for instructions.
THESE INSTRUCTIONS MAY NOT COVER ALL DETAILS OR VARIATIONS OF THIS PRODUCT FOR YOUR EQUIPMENT OR INSTALLATION REQUIREMENTS.
SHOULD FURTHER INFORMATION NOT COVERED BY THESE INSTRUCTIONS BE REQUIRED, PLEASE CONTACT LARSON ELECTRONICS BY EMAIL AT
SAL[email protected] OR BY PHONE AT 1-877-348-9680 FOR FURTHER ASSISTANCE.
PLEASE VISIT LARSONELECTRONICS.COM FOR WARRANTY AND RETURN INFORMATION.
USE AND CARE
Unauthorized modification may impair the function and/or safety of this device and could affect the life of the equipment.
Always check for damaged or worn out parts before using the device. Store it in a secure place out of the reach of
children when not in use.Inspect for good working condition prior to storage and before re-use.
REPLACEMENT PARTS
The EXP-TSTAT-125.250-60.250F-0.25-V1-15L is designed to provide years of reliable performance. Should the need
for replacement parts arise, please contact Larson Electronics.