Yes, it matters a great deal. The sensors supplied with controls in the U.S. historically have come in two different formats; lug and probe. Traditionally, the probe sensor has been designed for a thermocouple well in a storage tank leaving the lug sensor to be mounted on the collector. This is no longer the case. With the huge success that Steca has had penetrating the market with their 0301 control there is now a change that installers need to be aware of. The Steca 0301 control comes equipped with two sensors; a probe sensor for mounting on the collector and a lug sensor for mounting on the tank. That’s right, the probe sensor is designed to be mounted on the collector. Steca’s probe sensor is designed to handle temperatures up to 356 degrees F while the lug sensor is only designed for temperatures up to 221 degrees F. If you use the lug sensor on the collector you are asking for a service call back because of a premature sensor failure.
Probe sensor and lug sensor for Steca 0301 control. The probe sensor is designed to take the higher temperatures on the collector the lug sensor is not.