Air-Fuel Ratio (AFR) Sensor

Your tankless water heater continuously monitors combustion to maintain the ideal air-to-fuel ratio. By automatically adjusting fan speed, it ensures optimal performance, reduces emissions, and improves overall efficiency.

Venting

Indoor condensing models monitor exhaust temperatures to ensure safe PVC venting. If temperatures approach unsafe levels, the thermistor and hi-limit switch adjust combustion or shut the unit down entirely. to protect the venting material.

Hi-Limit Switch

The hi-limit switch prevents water temperatures from exceeding safe limits. Inlet and outlet thermistors monitor the temperature, and if it surpasses 185°F or 194°F (depending on the model), the switch disengages the gas valves, safely shutting down the heater.

Freeze Protection

Every tankless water heater includes built-in freeze protection. Standard electric heaters and, in some models, a brief burner cycle help keep the heat exchanger from dropping below safe temperatures. For added protection in colder climates, we recommend indoor installation to avoid direct exposure to freezing conditions.

Overheat Cut-Off Fuse

To prevent overheating, each tankless unit includes an overheat cut-off fuse. This safety device shuts off the gas valve if a breach in the heat exchanger wall or a failed gasket causes the wire to sever, helping protect your system from potential damage.