This article was posted on Friday, Dec 01, 2017

Commercial gas fired water heaters fail in much shorter periods of time then residential water heaters. The manufacturers are all aware of this fact; consequently commercial water heaters are provided with shorter warranty then the water heaters we all use in our homes.

Approximately 75% of commercial water heaters will ultimately fail due to depletion of the anodes. This is the most common cause of tank failures. Poor welding, metal fatigue caused by excessive lime scale buildup on the tank bottoms, and poor glass glassing account for the balance. Lime scale can be controlled to a certain extent by following the manufacturer’s maintenance instructions, but the other conditions are solely in the hands of the tank manufacturers. In the case of anodes however, the end users now have some direct control and how long the water heater tank may last. The manufacturers of course, desire to provide sufficient anode coverage so that the heaters will last through the warranty periods. In some installations the tanks will last longer but this is not the general rule. When high volumes of hot water pass through the commercial water heaters and high-temperatures are used, the glass lining is eroded. This erosion of the porcelain or glass lining is similar to what you see happening to the rocks in the stream beds as water continually flows over them. As soon as the erosion of the glass lining exposes any bare spots on the metal in the tanks, the anodes go to work coating these areas in preventing corrosion.

Although bare spots can show up anywhere inside the tank, they are most likely to occur in the tank head or bottom since these areas are often subject to thermal flaking as well as well splatter when the flues are welded to the head and bottom. Since the introduction of glass lining in the early 1960’s, manufacturers have installed anodes in the tank heads as a matter of simplicity and economy even though anodes will protect the entire tank interior regardless of where they are installed.

Anodes will dissipate the fastest where water softeners are used or compound containing phosphates are added to water to control lime scale accumulations. Test and studies conducted by the Gas Research Institute found it was not uncommon for anodes to become completely dissipated in little as 18 months under such conditions. The test revealed that an old coverage was the surest way to prevent premature tank failure.

When the annals of depleted and the tank fails after one year of service, the water heater manufacturers do not cover the replacement labor required for installing new water heaters even though the tank themselves may still be covered by their warranties. Consequently a warranty replacement can often cost the end users user as much as a thousand dollars. Worst yet, if a leak occurred after the warranty has expired, the owner must pay installation labor for the replacement of the water heater along with the higher cost for the most of today’s new model’s. In many cases these cost maybe twice as much as the cost of the original heaters.

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With both the cost of labor and prices of water heaters rising yearly, the importance of extending tank life is obvious. Tank life can be extended by the following two simple rules. First and obvious, the manufacturers’ preventive maintenance schedules must be followed. Second, additional anodes should be added to all commercial water heater tanks if we want them to last beyond the manufacturers’ expectations. Manufacturers’ will double the six year warranty on residential heaters by installing second anode rod to the nipple on the hot water outlet. Anodes should be added, they should not be replaced. The ideal time to add anodes is when water heaters are installed, but it can also be done any time before rusting begins inside of the tank. Once the rusting begins, the rust (iron oxide) acts as an insulator, and anodes can no longer inhibit corrosion in the rusty areas. Tanks are doomed to failure, usually within one year.

It is very difficult and almost impossible to remove and replace anodes in commercial tanks without special equipment. The venting and plumbing has to be removed. The lid to the heater removed with flue collector to access the four anode rods. Even with the special equipment, the work is very costly due to the amount of time and material required to disconnect a commercial water heater, perform major disassembly, remove and replace anodes after they have been locked in position for years, re-assemble the water heaters and then put them back in service. There are a few companies that specialize in plumbing maintenance and they have the special equipment to do the job properly, but this is very difficult task that requires hours of labor even with the right equipment.

Now it is no longer necessary to attempt to replace anodes in commercial tanks. You merely add Maganodes to the tanks and there is a simple and inexpensive way to do it. All that needs to be done is to open the hand hole clean up and place the Maganodes in the tank. All that then remains to be done is to place the grounding wire in position in the cleanout opening and the job is complete. The two inch diameter Maganode will provide tank protection equivalent to a conventional type anode old forty-two inch in length. When a Maganode is added to a new tank, you will be assured of additional protection from the day the water heater is installed. Two or more Maganodes can even be installed in a tank at the same time and they will work together with the existing anodes to add years and years of life to the commercial water heater tank.

The exhaust vent, plumbing, lid to heater and flue collector all have to be removed to gain access to the four anode rods. A _” heavy duty socket and breaker bar or pneumatic hammer has to use to remove rods. The re-installation of the rods, heater, plumbing and venting is costly.

Needless to say it’s far too expensive and inconvenient to tenants and therefore preventative maintenance is not performed as recommended by all manufacturers.


Bill Provin is President of General Installation Company and has performed service for the water heater industry since 1959. General Installation Company currently provides in and out of warranty service to American Standard, A.O. Smith, Bradford White, Rheem, American Water Heater Co and State Water Heaters. For more information log onto:, or call 800-824-1117.