I have infloor electric heating installed in our bathroom. The power is supplied by a dedicated 240V/1Ph. circuit that also feeds a couple of baseboard heaters in our bedroom. The infloor heating is controlled by an electronic wall mount thermostat that incorporates GFCI protection. The problem is that the thermostat (GFCI) trips off line whenever the bathroom exhaust fan is switched on or off. The fan is completely isolated from the heating power supply and runs on a separate 120V circuit. What gives? Any ideas?