How Do Continuous Flow Water Heaters Work?

February 13, 2019

Like most water heating systems, copper pipes are working industriously under the hood of this appliance. But they’re not just transporting the hot liquid, nor are they storing the water. No, in continuous flow water heaters, copper pipes function as the central heating elements within the heater housing. They receive cold water, just like any other appliance in this class. From here, though, the operational mechanics alter significantly.

A Hot Copper-Tubed Heart

In place of a standard dip tube and a group of water-transporting copper tubes, plus that all-important storage tank and elements, the design is condensed down to a much more efficient water heating configuration. The thermal energy is delivered straight to the copper tubes, which curve and corkscrew around a system heat exchanger. A compact burner unit is located below this heat exchanger assembly. It lays inactive until a hot water tap is turned. And that’s the secret to its success, an electronically ignited burner, one that’s not ceaselessly warming a storage tank.

An Electronically Ignited Fire

Without a pilot light or an inefficient appliance thermostat, the microprocessor controlled ignition delivers high-tolerance temperature control. The heat is controllable to plus or minus a single degree Celsius, in other words. Now, having framed the basic building blocks, let’s go deeper. That heat exchanger doesn’t operate by itself, there are feedback-tuned components that converse digitally with the microprocessor managed burner. For example, there’s a water mixing valve and flow sensor located inline. They’re positioned way back at the cold water inlet tube. For the hot water outlet, a temperature sensor safely controls the thermal characteristics of the outgoing stream, so a bather is always protected from scalds.

Opting For an Electrically Powered Counterpart

Gas-fueled models are more efficient than their electrically powered counterparts. Generally speaking, the fan and gas burner configuration operates superbly when paired with an ignition and fuel regulating assembly. However, especially when gas isn’t available, an electric appliance may be the only workable option. In this case, the burner/fan module is replaced by a number of elements, which are designed to instantly heat those same cold water-carrying copper tubes. Heat exchanger technology still applies here, but the required quantity of electrical energy may make the option less desirable, particularly when used in a region that uses high electrical energy tariffs.

Short-circuiting old design approaches, the storage tank is dropped from the appliance blueprint. On continuous flow water heaters, it’s the heat exchanger, ignition microprocessor and tightly arrayed package of copper tubes that sits at the heart of the design, not an inefficient, energy-sapping storage tank.

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