It's an eEMAX whole house unit. It has 4 coils of which some or all are supposed to come on depending on how much water is being used. Price wise it was in the middle of the pack. I have another eEMAX in my workshop. It is a single point of use unit that doesn't work either. On that one they tested the water flow rate and determined that it wasn't enough to trigger the unit. It needs 1.5 GPM and the faucet is less than that.
Speaking of which, is water pressure concurrent with GPM flow rate? In other words does increasing the pressure increase your GPM?