Thermostats, Switches and Indicators

A cooler fan that runs all the time wastes power and wears the motor out early. These are the parts that tell the fan when to run, and the parts that tell you when something needs attention. Most of it screws into a 1/2 inch BSP port in the rail or the tank.

Which control do I need

Decide how much control the machine actually needs.

• On and off at one temperature. A temperature switch does that on its own.
• Fan speed that follows the oil. A proportional sensor and a controller, because the sensor does nothing by itself. The fan starts at 45C and reaches full speed at 55C.
• A core that keeps blocking with chaff. The reversing controller spins the fan backwards to blow it out.

Fitting it and what else you need

The controllers suit LL04 and LL06, the TT07 to TT36 rail coolers and ASA0177 to ASA0367. Put the probe where it reads oil, not tank steel, or the fan chases a temperature the oil never sees. Torque it properly, 40 Nm on the ILLZTH switches and 50 Nm on ILLZTH7067K and the sensors. Pick the connector to suit the machine: AMP Superseal 1.5 at IP69K for washdown and mobile work, ISO 4400 at IP65 for a cabinet, Deutsch DT06-2S at IP67 for harness work. Size the fuse on inrush, and fit two controllers to a twin-fan cooler. Fans are under fan kits and cooler spares, and the coolers these suit are under air blast oil coolers.

Common questions

Can I run a sensor without a controller? No. A sensor is only a signal, and without a controller nothing switches. A temperature switch is the part that works alone.

Which setpoint should I pick? Set the fan to come on well before the oil is in trouble. A 60C or 70C switch is the usual choice, and 50C suits a system held cool.

My twin-fan cooler has one controller, is that a problem? Yes. Each fan needs its own controller, and the draw is double the single-fan figure.

Does a bypass valve replace a thermostat? No. A bypass protects the core from cold oil, and a thermostat decides when the fan runs. Most machines want both.