Product Specifications

Time Delay Relays and Sequencers

The Therm-O-Disc type 12S, 14S and 15S series time delay relays and sequencers are field proven devices for controlling the operation of heating elements and/or fans in electric furnaces and heat pumps. These controls combine a solid state positive temperature coefficient (PTC) heater with bimetal actuated contacts to provide time-delayed electrical switching. A wide variety of bimetal disc and PTC combinations are available to provide a broad range of timings. The 12S is a single-timing device while the 14S uses two bimetal discs to achieve two independent timings. The 15S consists of one, two or three 12S and/or 14S controls mounted on a common plate.

Features and Benefits:

• Available with auto-reset SPST, DPST and SPDT switch configurations.

• PTC heater for stable operation over a wide range of temperatures and voltages.

• Snap-action bimetal disc for high-speed contact separation.

• Standard operating ambients between -40°F (-40°C) and 150°F (65.6°C).

• Available with a wide variety of terminals and mounting plates.

• Welded construction for integrity of current carrying components.

Switch Actions and Configurations:

•Automatic Reset SPST – This 12S or 14S configuration can be built to either open or close a set of contacts on temperature rise within a specified time range.

•Automatic Reset DPST – This 12S configuration utilizes one bimetal disc to simultaneously open or close two independent sets of contacts on temperature rise within a specified time range.

•Automatic Reset SPDT – This 12S configuration is the same as the SPST except with the addition of an auxiliary contact that makes and breaks circuit in opposition to the main contacts.