July 16, 2020

Replacing anode can double life of hot water heater

Barbara opened the hot water tap yesterday to fill up her tea kettle and found that she didn’t need to waste a tea bag. Her house water was already tea colored.

“Water heater’s gone,” we told her.

“But it’s only 5 years old!”

“Yep, that’s just about the life span of an anode.”

The plumber arrived the next day with a new 10-year (“double anode, double duty,” he boasted) water heater and departed with 550 of Barbara’s hard earned retirement dollars.

Anodes are metal (usually magnesium) rods found inside the water heater tank. Their role is purely sacrificial. The anode protects the iron tank from its worst enemy — rust — by allowing mineral salts in the water to slowly corrode and consume it, rather than the tank.

As soon as the anode is spent (usually five years, thus, the standard five-year warranty on most water heaters), the tank walls begin to rust at dozens of tiny points in its imperfect glass lining. Soon after, hot water taps begin to yield that telltale tea-colored water and finally, the tank springs a leak.

You can almost double the life of your tank, however, simply by changing the anode before it is depleted (about $20).

Before unplugging your only hot water supply, check the make and model number on your heater and buy an exact replacement anode from a heating supply company. Then, close the tank’s cold water supply valve and turn off the gas control knob or circuit breaker. Drain a couple of gallons of water from the tank through the drain valve near the bottom of the tank.

Using a socket wrench, loosen the hexagonal anode plug found on the top of the tank by turning it counterclockwise. If the plug is rusted in place, a long-handled wrench will lend extra leverage. Finish unscrewing the rod by hand, then lift it straight out of the tank.

Apply a single wrap of pipe tape to the threaded end of the new anode, insert it into the tank, screw it into place, then tighten it (clockwise) with the wrench.

Tank tips

Some types of minerals in water react with magnesium anodes to create an unpleasant, “rotten egg” odor. Substitute an aluminum anode to solve this problem.

Drain sediment from your water heater at least once a year and lower its thermostat(s) setting(s) from the standard 140 degrees to 115 degrees to save energy dollars and lengthen the tank’s life.

If your old water heater has left you cold one too many times, you may want to look at the hot new “leak-free” tanks on the market.

Redesigned tanks from industry leaders State Industries and Ruud/Rheem are lined with Duron, a high-tech plastic that is heat-bonded to a drawn steel tank. The result is a strong outer tank with a seamless plastic shield facing the corrosive water … and no anode.

State’s lifetime electric water heaters start at $500; gas-fired models are still being perfected by the manufacturer. Rheem tanks can be special ordered through local heating suppliers for about $650. Sear’s answer to the electric lifetime tank, the polybutylene-lined “Survivor,” starts at about $400.

The manufacturers offer lifetime warrantees to the original owner.

With their increased efficiency and extended warranty, these new tanks’ high initial cost can actually become a net gain over the years.

Doug and Cynthia Edmunds are renovators from Kittery.

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