The Vernet cooling fan thermocontact, with an M22x150 thread, activates the fan when the temperature reaches 82 °C and then shuts it off when the temperature drops back to 68 °C at the thermocontact.
These temperatures are fixed and cannot be adjusted. The 14 °C difference between the activation and deactivation points—known as hysteresis—keeps the fan running as the temperature drops to 68 °C. This limits repeated cycling around the activation temperature.
Selecting the Proper Temperatures for the Engine
Each engine has an optimal operating temperature range defined by its manufacturer. The choice of thermocontact must meet the engine’s requirements and be consistent with the thermostat, the radiator, and the location of the thermocontact within the cooling system. An earlier fan activation is not necessarily beneficial.
The temperatures of 82 °C at activation and 68 °C at deactivation correspond to the temperature at the thermocontact. They do not, on their own, define the engine’s optimal temperature and should not be confused with the thermostat’s opening temperature, which regulates cooling fluid flow.
Mounting Tips for the Vernet Thermocontact
Use an adapter on the cooling hose with an M22x150 thread, matched to the hose’s inner diameter, or use an available location with the same thread on the cooling system. The thermocontact element of the Vernet thermoswitch must be in contact with the cooling fluid. Check the available space, the connections, and the seal of the mounting.
Installation with a relay: The thermocontact must be connected to the control circuit of a relay, not to the power circuit. It controls the relay coil, while the relay’s power contacts supply power to the fan. Do not power the fan motor directly through the thermocontact.
Use a relay, a protective fuse, and cables with a cross-section suitable for the fan’s consumption, taking its starting current into account. Follow the wiring diagrams for the relay and the vehicle.
Technical Specifications of the Vernet M22x150 thermocontact
- Brand: Calorstat by Vernet.
- Manufacturer part number: TS6993.
- Product type: cooling fan thermocontact.
- Trigger temperature: 82 °C.
- Shut-off temperature: 68 °C.
- Temperature settings: fixed temperatures, not adjustable.
- Switching hysteresis: 14 °C.
- Thread: M22x150, with a nominal diameter of 22 mm and a pitch of 1.5 mm.
- Mounting: on a hose adapter or any available mounting location with an M22x150 threaded hole.
- Electrical connection: relay control circuit; direct power supply to the fan is prohibited.
Key features of the Vernet thermocontact
- Automatic fan start and stop based on temperature.
- Separate activation and shutdown temperatures to limit frequent switching.
- Fixed calibration requiring no temperature adjustment.
