A tankless water heater is a very small but very powerful and extremely efficient electric water heating system. The tankless water heater, whose technology has earned 5 U.S. Patents and many more foreign patents, is much more than just a water heater.
There are two high limit switches located near the top of chambers 1 and 3 in line across with thermistors TH1 and TH3. There are two brown wires connected to each high limit switch.
Figure: High limit switch, reset button shown in the middle between the two spade connectors.
Remove the two brown wires with needle nose pliers and use the same tools and procedure above that are described for TH1 through TH4 thermistor replacement. Again, only tighten the high limit switch to 14 in.-lbs. (same tightening torque as the thermistors)
