Tankless water heaters can provide a virtually constant, uniform hot water temperature on demand, unlike their traditional, storage tank-based counterparts. Consumers can typically save up to 40 percent in annual energy costs versus tank-type water heaters. To enjoy the full benefits of tankless water heaters, the system must receive routine maintenance, as it’s a key component for a long service life and high performance.
Maintenance Service Checks
By conducting proper recommended maintenance, tankless units are expected to last far longer than tank-type units. While a conventional water heater typically requires replacement every seven to 10 years, the tankless model could last up to 20 years with recommended annual maintenance. Before servicing any tankless water heater unit, always shut off the electrical power supply, manual gas valve and water valves. Annual maintenance includes inspecting the venting system, combustion chamber, burner, pressure relief, water filter and condensate trap. Maintenance also includes descaling the heat exchanger yearly and cleaning the fin coils of the heat exchanger bi-annually (every two years). Examine the water heater and its components for wear or fatigue and immediately repair all faults to avoid damage to the system.
Know the Water Quality
Water quality can have an impact on appliance longevity and may void the manufacturer’s warranty, as well. For water analysis data call your local water department, or if on a well, have well water analyzed periodically. If the tankless water heater is operating in applications where the outlet temperature exceeds 140°F, a water softening system is strongly recommended. The higher the set temperature is on the appliance, the greater the risk for scale/mineral deposits.
Minimize Scale Buildup
In areas where the water supply has a high mineral content, the heat exchanger should be flushed with a descaling solution. Scale buildup will shorten the life of the water heater and damage resulting from scale may not be covered under the manufacturer’s warranty. A water softener is required if the water hardness exceeds 6 grains/gal (180 mg/l) calcium carbonate. In the Bosch Greentherm 9000 series, the unit’s lifespan is aided by a primary copper heat exchanger and a secondary stainless steel heat exchanger to minimize scale buildup.
Winterize Your Unit
In addition to routine maintenance, tankless water heaters should also be winterized for seasonal use. If the unit must be installed in a location where it may be exposed to freezing temperatures, all the water needs to be drained from the heater. For full details on maintenance and winterizing tankless water heaters, always consult the manufacturer’s installation and maintenance instructions.
Like check-ups at the doctor and car inspections at the auto shop, routine maintenance on tankless water heaters helps address any repair issues early and ultimately extends the life of the unit.
Craig Porter, Bosch Thermotechnology