Product Specifications

Moisture Resistant Temperature Control

The 37T series of 3/4” (19mm) bimetal disc thermostats from Therm-O-Disc® offers proven reliability in a moisture resistant sealed design. The snap action of the bimetal disc provides high-speed contact separation resulting in excellent life cycle characteristics at electrical loads up to 10 amps at 120VAC and 5 amps at 250VAC. The sealed design provides moisture resistance for moisture prone environments. A wide variety of terminal, lead wire and mounting configurations are available to provide maximum design flexibility. The 37T is the most popular and widely applied thermostat in refrigeration applications such as defrost termination and ice cube maker control. It is also applied in a range of heat pump and air conditioning applications.


Features and Benefits:

• Sealed construction provides moisture resistance for moisture prone environments.

• High-speed contact separation ensures long contact life.

• A wide variety of mounting configurations, lead wires and terminations provide maximum design flexibility.

• All materials have been selected to pass the refrigeration industry’s odor and taste tests.

• The use of statistical process control techniques in all phases of the manufacturing process results in consistently high quality levels.

• Controls are 100% operation checked and dielectric tested.

Switch Actions and Typical Applications:

Automatic Reset SPST – In this design, the switch can be built to either open or close its electrical contacts on temperature rise. Once the temperature in the application has returned to the specified reset temperature, the contacts automatically return to their original state. Open on rise contact design is typically used for refrigeration defrost termination and ice cube maker control. Type 37TF includes an internal resistor wired in parallel with the contacts which serves as an aid to factory circuit testing where the contacts are open at room temperature.

Automatic Reset SPDT - This design is the same as the SPST with the addition of an auxiliary contact which makes a circuit upon the opening of the main contacts and breaks the circuit when the main contacts reset. In this design, any combination of electrical ratings shown in the rating table may be switched from one circuit to the other.

Mounting Configurations:

No Mounting Bracket – The 37T may be specified without a mounting bracket. The 37T is available with a polyethylene cap or a phenolic centerpost which may be used for a customer’s bracket. The phenolic centerpost may be customized to meet unique requirements.

Surface Mounting – The surface mounting configuration positions the sensing element firmly against the surface to be monitored.

Clip-in Mounting – Clip-in mounting brackets hold the sensing element firmly against the surface where the thickness of the surface is from .03” (0.8mm) to .06” (1.5mm).

Tube Mounting – Several different tube mountings are available. These brackets firmly attach the 37T to tubes ranging from 1/4” (6.4mm) to 7/8” (22.2mm) in diameter.

Lead Wire and Terminal Configurations:

Standard Lead Wire – The standard leads for the 37T controls are 12” (305mm) #18 AWG, 16/30 standard copper wire with 1/32” (0.8mm) thick 105°C PVC odorless insulation stripped 1/2” (13mm).

Non Standard Lead Wire – Leads longer than 12” (305mm) are available for all 37T controls at added cost. The standard lead wire can also be supplied with tracer or with 1/16” (1.6mm) insulation. In addition, #16 AWG wire can be supplied with either 1/32” (0.8mm) or 1/6” (1.6mm) thick insulation. The maximum wire size available is #14 AWG with 1/32” (0.8mm) insulation.