Thermotech 302 Series
Heat Detectors
Features
• Hermetically sealed and explosion-proof options
• Horizontal or vertical mounting ability
• Select models available for indoor and outdoor use
• Aluminum tubing with silver contact points
Description Technical Specifications
Each model is a normally open device designed especially for
Electrical Ratings
fire detection and alarm systems. These rate compensation type
detectors are available in either 135°F or 194°F ratings. All four Voltage Current
basic models are self-restoring, hermetically sealed, shock and 6-125VAC 5 Amps
corrosion resistant, and are tamper-proof.
6-25VAC 1 Amp
All models operate on the principles of a rate compensation 125VDC 0.5 Amps
detectors. The detector consists of a high expansion aluminum
tube which encases two insulation struts with opposing open Temperature Ratings
constant points. The high expansion sensing shell and the Device Temp Rating Max. Ceiling Temp
expansion struts have a different co-efficient of expansion. A
slow rate of temperature rise allows the heat to penetrate the 135°F 115°F
inner expansion struts. Therefore, the tubular shell and the 194°F 155°F
struts expand slowly until the total device has been heated to
its rated temperature level of 135°F or 194°F. At this point, Detectors are not directionally affected, can be mounted
the silver contact points close which initiates the alarm. When horizontally or vertically. Detectors have a smooth ceiling
subjected to a rapid temperature rise there is not as much time UL rating of 50’ x 50’ (2500 sq. Ft.) on 8 to 10 ft. ceilings.
for heat to penetrate the inner strut. The rapid lengthening of the Detectors, hub covers, or outlet boxes must never be installed
shell allows the struts to come together at a lower level which in direct sunlight. Refer to NFPA Standard 72 for spacing and
compensates for thermal lag inherent in conventional fixed other considerations.
temperature detectors. When the surrounding air temperatures
go below the rated temperature level, the shell contracts which
forces contacts to open, which automatically resets the detector.
Potter Electric Signal Company, LLC • St. Louis, MO • Phone: 800-325-3936 • www.pottersignal.com
8820047 REV A 1/19 page 1 OF 2
Thermotech 302 Series
Heat Detectors
Model Descriptions Ordering Information
Model 302
Model Ordering Part Description
For interior mounting in any atmosphere that is compatible
Number Number
with terminal screw type connections.
302-135 1430475 Heat Detector, 135 Deg.,
Model 302-ET Vertical Mt., Interior
Hermetically sealed for moisture proof or dust proof 302-194 1430476 Heat Detector, 194 Deg.,
installations. Requires no special back box. Has plastic Vertical Mt., Interior
hexagonal grip bushing with 1/2” conduit threads hub cover 302-ET-135 1430477 Heat Detector, 135
for any outlet box. Must be hand tightened only. For indoor Deg., Vertical Mt., Hex
and outdoor use. Protect from sunlight and adverse conditions Bushing, All-Weather
(may mount horizontal)
Model 302-EPM
302-ET-194 1430478 Heat Detector, 194
Explosion-proof for installation in hazardous locations.
Deg., Vertical Mt., Hex
Has hexagonal grip bushing with 1/2” conduit threads for
Bushing, All-Weather
attachment to threaded hub cover of series JL fixture fitting as
(may mount horizontal)
manufactured by Killark Electric Co., or equal. Must be hand
tightened only. For interior use. 302AW-135 1430479 Heat Detector, 135 Deg.,
Vertical Mt., All-Weather
Model 302-AW 302AW-194 1430480 Heat Detector, 194 Deg.,
Hermetically sealed for moisture proof or dust proof Vertical Mt., All-Weather
installations. Requires no special back box. For indoor and 302EPM-135 1430481 Heat Detector, 135 Deg.,
outdoor use. Protect from direct sunlight and adverse weather Explosion Proof
conditions
302EPM-194 1430482 Heat Detector, 194 Deg.,
Explosion Proof
AP-P 1430483 Decorative White
Plastic Adapter Plate for
mounting 302, 302ET and
• Installation must be performed by qualified personnel 302AW to any 3” outlet
and in accordance with all national and local codes and
ordinances. box or 4” octagon outlet
• Shock hazard. Disconnect power source before box
servicing. Serious injury or death could result.
• Read all instructions carefully and understand them
before starting installation. Save instructions for future
use. Failure to read and understand instructions could
result in improper operation of device resulting in
serious injury or death.
Potter Electric Signal Company, LLC • St. Louis, MO • Phone: 800-325-3936 • www.pottersignal.com
8820047 REV A 1/19 page 2 OF 2
