No Safety Issues For Tankless Water Heater
None of the safety issues of tank water heater applies to tankless water heaters. Their burners come on only when hot water is needed, they don’t have a permanent pilot.
The gas burner is electronically ignited and if installed outside it constantly monitors the outside temperature and activates its anti freeze circuitry preventing a pipe freeze when needed. Its electronics also monitors incoming water pressure, flow and regulates outgoing hot water pressure and flow. The highly efficient burner and heat exchanger achieve high efficiency and save energy.
Incoming gas volume and pressure is also monitored and in case of a malfunction the unit shuts itself off and provides diagnostic information. Takagi TK 3 is closely related to Noritz 751 and is also able to supply an entire house with hot water. Another saving aspect of tankless hot water heater is that since you never run out of hot water there is no need to mix the hot water with cold water and therefore the water temperature can be set lower.
For example the tank water heater is typically set to 160 to 180 degree F even though the water temperature used for shower is roughly 105 degree F. This is done to not use so much of the hot water in the storage tank and make the hot water last longer by mixing it with cold water at point of use. With tankless water heaters there is no need for this, there is endless hot water and therefore the temperature can be set to 110 degree F and there is no need to mix as much cold water.
That saves energy too because the water is not heated to the higher temperature. Any time cold water is mixed to the hot water that reduces the efficiency indirectly. Tankless water heaters are green products and help reduce the carbon footprint.