Bühler TSM series unit with two temperature contacts, at 55 °C (NO) and 80 °C (NC), 250 mm stem and G1/2 thread.
Bühler TSM series unit screwed into the tank, with brass (MS) body, G1/2 thread, 250 mm stem and M3 connector (3 pins + earth). In the Bühler product overview, the TSM series is listed among the bi-metal temperature switches.
The code gives two temperature contacts: TM55NO, normally open, which closes at 55 °C, and TM80NC, normally closed, which opens at 80 °C. On a power unit, the first can, for example, switch on the cooler and the second raise an alarm or stop the pump.
The TSM-2 data sheet is in the attachments. Check the stem length: it must stay immersed in the oil even at minimum level.
Source: Bühler Fluidcontrol Quick Product Overview technical catalogue; Bühler Nivotemp NT M, NT MD data sheet, DE100211, 01/2022.
Data sheet
Specific References
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