At the push of a button, the Metlund Hot Water D''MAND System circulates the ambient temperature water in the hot water pipes (water that is normally lost down the drain) back to the water heater.
This occurs up to 80% faster than just letting the water run down the drain—the usua l scenario. Depending on the plumbing layout, the route and time can vary. The Metlund D''MAND System moves the water so rapidly, that hot water arrives at the fixtures before the heat is lost through the pipe.
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As the ambient temperature water in the cold water line travels towards the hot water heater, the D''MAND System fills the hot water line with hot water. When the hot water reaches the D''MAND System, a thermal sensor (thermistor) senses a temperature rise and quickly closes the zone valve while it shuts the pump off. The sophisticated electronic circuitry that does this is attached to the high-performance pump housing.
This results in getting hot water to the fixtures four to five times quicker (on average), greater convenience in not having to wait, a savings in water and energy, and a reduction in sewage costs. As a by-product of these savings, a cumulative result is the improvement of air quality.
The Metlund D''MAND System can utilize the cold water line as a return line or use a dedicated return line. By using the existing cold water line, it is easy to retrofit existing homes or businesses. Special plumbing is not needed, and since the System will not allow for hot water to cross over to the cold water line, all the cold water fixtures still have cold water.
Activating the System
Every model of the D'MAND System can be activated by one or more methods.
A small doorbell-type button connects to the electronic controller by a 12-volt, 18-gauge standard bell wire. These buttons may be placed at one or all locations where there is a demand for hot water. This type of activation is commonly used on new home construction or remodeling of existing homes.
Wireless Remote Control
A small receiver is connected to the master controller. Small remote control buttons can be placed at any location in the home. Working on radio frequencies, a signal can be transmitted up to 100'' through walls. This method of activation is most common on existing homes where the wiring for the D'MAND button (mentioned above) is difficult to install.
Low voltage breakers can be placed on doors to allow for automatic activation when a door opens or closes. This is most commonly used for public restrooms in restaurants, factories, hospitals, etc.
Motion Sensors are adaptable to both new homes and existing homes. On new homes, they are hard-wired by low voltage wires to specific locations that require hot water use. For existing homes, wireless motion sensors are available that will send signals up to 100 feet to activate the D'MAND System. Motion Sensors are designed not to allow activation of a subject under 4 feet high or 40 pounds of weight.