Water heaters protect their tanks using what are known as sacrificial anode rods. These are metal rods which are suspended inside a water heater so that they are surrounded by the water in the tank. The metal rods are more susceptible to corrosion than the tank walls. The result is that the rod will corrode instead of the tank: extending the lifespan of the water heater.
The principle is called anodic protection. The metal in the tank is steel while the metal in the anode will deteriorate in a process known as electrolysis. Some extended warranty tanks include two anode rods for additional protection and redundancy.
It is good practice to inspect the condition of your tank’s anode periodically. You can check your water heater user manual for the recommended interval s between replacements. At a minimum these should be checked every two years. Once corrosion has eaten away the metal of the anode rod it must be replaced with a fresh one to maintain tank protection. The life span of the rod depends on usage, water quality, and temperature.
When a water heater is located in a tight area such as a closet or crawl space removing/installing a new anode can be tricky due to the long length of the rod. With a traditional rod the method used involves disconnecting the water lines and tilting the entire tank to create enough headspace to remove the rod.
To solve this common issue Water Heater Smart offers a line of flexible anode rods. Their flexible anodes are composed of linked sections of metal, allowing installation in as little as 12” of clearance above the tank.
Anode Rods may be composed of either magnesium or aluminum
Magnesium – These are the most common anode. They will provide the best protection level to the tank. Unfortunately if there is a water softener on the system it will accelerate the anode’s breakdown and the tank will lose protection more quickly. The Blue Lightning Anode Rods are composed of Magnesium mounted onto a steel rod core, and the links are joined with stainless steel braided wire.
Aluminum /Zinc – These anode rods will control a rotten egg smell which results when there are specific types of bacteria present in a water system. This is a known issue prevalent in certain well water systems.
There are two types of connections found on most anodes. The most common type is the plug style. These are most commonly a 1-1/16 socket. These are installed very tightly at the factory and removal of an old rod may require the use of a breaker bar or an impact wrench. This will leave a hex plug exposed on the tank jacket. On newer water heaters these are found beneath insulation while older ones it may have it clearly visible.
Bradford White branded water heaters use a nipple style anode rod.
If the water heater is very old and the nipple is rusted a nipple extractor should be used to prevent crushing or collapsing.
When installing the new flexible rod it is important that the rod not touch any part of the tank interior. The sections can be carefully cut to fit using a metal hacksaw or the stainless steel connecting wire can be cut using wire cutters. The goal is to include as much of the anode as will fit in the tank without contact to provide the longest protection.