Hard Water and Your Tankless Water Heater

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All water heaters are susceptible to the same problem – the buildup of calcium and other hard water compounds that are released from water during the heating process. Although we may not want to admit we have the problem with our water you need only look to those unsightly white deposits that accumulate in showers, on faucets and on your cookware. These compounds, typically a form a calcium carbonate, are dissolved in potable water and are invisible, while other compounds are held in suspension and may not be visible to the naked eye. When water evaporates the dissolved and suspended solid compounds remain and this is what leads to buildup in our showers and deposits on our fixtures.

Whether your water comes from a tap or from well filtered well water the problem remains. The only process that effectively removes these compounds is reverse osmosis. In many areas, including the Southern States in particular, potable water is extremely hard. The “hardness” of the water is related to the existence of dissolved calcium or magnesium compounds. Hard water in most homes is addressed by using water softening devices that use salt to remove the calcium or magnesium ion from the water. When this ion is replaced with a sodium ion the water becomes “soft” and less susceptible to causing buildup in pipes and on fixtures. Despite using a water softener or water filtration.

When potable water is flash heated by your tankless water heater these compounds are released from the water and these solid compounds make their way into your homes plumbing system, or remain in the tankless heat exchanger. Overtime these deposits accumulate in the plumbing system of your home and inside your tankless heaters heat exchanger. As these solids continue to build up they coat the interior of the heat exchanger (or the immersion electric heating elements in the case of an electric tankless heater) and over time the thickness of the material acts as a blanket that actually inhibits the efficient transfer of heat. As a result your tankless water heater becomes increasingly inefficient and costly to operate. In severe cases, tankless heaters that have flow restricted compounds may become entirely clogged resulting in reduced and then blocked water flow within the heater.

While water softeners reduce this hard water build up they have their own drawbacks. Water softeners typically use salt and the softening process adds sodium ions to water. The sodium in the water typically causes premature rusting and corrosion of tank and tankless water heaters.

So what should a homeowner do? Clean and clean often. Most tankless water heaters have a procedure for flushing or chemically cleaning the heat exchanger. If properly installed, your tankless heater will have been installed with isolation valves (such as those available from the Webstone Valve Company: (www.webstonevalves.com) to allow the heater to be disconnected from the water supply and distribution lines of your home. Some tankless water heaters come factory ready for easy cleaning – such as SKYE’s FORTIS tankless heater (www.tankless.com) that incorporates a built in flush valve for easy cleaning. Once isolated from your homes plumbing system, most manufacturers recommend filling the heater with household vinegar or C.L.R® , and then allowing heater to clean itself through a chemical reaction between the build up and the chemical. After 20 -30 minutes the heater should be drained and well flushed to remove any chemical residue or loose deposits. This cleaning process should be done at least once per year, and in areas with particularly hard water, it may be necessary to perform this cleaning two or more times per year.

Always be sure to follow your manufacturer’s written instructions for detailed instructions on how to service your tankless water heater. If you want to speak to someone in the know, give your local plumber a call or call a Skye international customer service technician at 1-877-888-7593.

Next week – how a water softener works in your home.

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