Find here all the sensors and spare parts compatible with your Balboa heater.
The brand uses its M7 technology on all heaters designed for GS, GL and BP boxes: two equal sensors are mounted at the opposite ends of the element to determine temperature, flow rate, dry running cases, etc. These two sensors replace failure-prone mechanical pressure/flow switch and act simultaneously as temperature and Hi-Limit sensors and compare the temperature of the incoming water with that of the outgoing water. This technology works regardless of the direction of water flow in the heater. Older control systems with pressure switches use conventional temperature and Hi-Limit sensors.