When corrosion starts to set in on a water heater, the conventional wisdom is that it’s time to replace the system. Conventional wisdom is (mostly) right regarding this. If corrosion begins to appear on a water heater’s tank, there’s usually nothing repairs can do to remedy the problem; the water heater will soon start leaking without any way to stop it, making replacement a necessity.
This isn’t always the case, however. We’re going to look a little more into the facts of corrosion and water heaters to help you understand how water heaters avoid corrosion—until they can’t.
How Water Heaters Keep Corrosion Away
Considering that a tank water heater is a large metal appliance that contains water, why doesn’t it corrode early on? Shouldn’t corrosion be a common issue, rather than something that only crops up if the water heater is old or neglected?
The answer is that the modern storage tank water heater has a number of design features that help prevent corrosion and rust from affecting it for many years:
- Glass-lined tank: The water in the tank doesn’t have direct contact with the metal of the tank walls thanks to a glass lining.
- Expansion tank: This is a small air tank housed over the main tank of the water heater. It creates an air cushion with a membrane, allowing for relief on the water pressure inside the main tank. The presence of the expansion tank provides an air buffer for the water heater without allowing oxygen into the main tank, where it would encourage corrosion.
- Sacrificial anode rod: This is a rod made of two different types of metal that is runs through the length of the tank. The rod draws corrosion to it and away from the rest of the system: essentially, the rod “sacrifices” itself by rusting away instead of the water heater. The anode rod must be occasionally replaced since it won’t do any good after it completely corrodes. Water heater technicians will replace the anode rod regularly during maintenance.
Corrosion Is Often a Sign of Age
If you have had routine maintenance for your water heater (this should be done once a year), the system should be able to last for around 15 years. After 15 years, the chance of corrosion starting becomes greater. If the corrosion begins on a replaceable part of the water heater, such as the heat exchanger, sometimes it can be repaired. But we recommend having the entire system replaced if it’s already past the 15-year mark.
Corrosion can also occur on tankless water heaters, although it’s less frequent. It can occur because of leaks onto the burners. Repairs can clean or replace the burners. If you notice a drop in the energy efficiency of a tankless water heater, corroded burners may be the trouble; call for our repair technicians to look into it.
If you need services for your tank water heater in Clovis, NM, always Call a Carpenter! We serve the Clovis area with excellent plumbing service, and we’re family-owned and operated. You can count on us to handle repairs or replacements—whatever you need for a dependable water heater for your home.