Tankless Water Heater Maintenance in Tampa's Hard Water

Tankless water heaters give you endless hot water and can last longer than a tank, but only if they're maintained. In Tampa Bay, the biggest threat to a tankless unit is the same thing that wears out tank heaters: hard water. Here's what maintenance a tankless heater needs and why it matters here.

Why Hard Water Is Tough on Tankless Units

A tankless heater warms water as it flows through a heat exchanger, a set of narrow passages that get very hot. When hard water heats up, calcium and magnesium come out of the water and stick to those passages as scale. Scale insulates the heat exchanger, so the unit works harder, heats less efficiently, and in time can overheat or shut down. Left long enough, it can damage the heat exchanger, which is the most expensive part of the unit.

Signs of Scale Buildup

• Hot water that swings between hot and lukewarm
• Lower hot water flow than you used to get
• Longer wait for hot water
• The unit shutting off during use or showing an error code
• New noises from the unit while it's heating

Many units display an error code when scale builds up. Your owner's manual lists what each one means.

Descaling: How It Works

Descaling, also called flushing, circulates a descaling solution through the heat exchanger to dissolve the scale. Most tankless installations have two service valves with small ports under the unit for exactly this:

1. The heat source is turned off and the water supply valves are closed.
2. Hoses connect the service ports to a small pump sitting in a bucket of descaling solution or white vinegar.
3. The pump circulates the solution through the heat exchanger, usually for about an hour.
4. The unit is flushed with clean water, the inlet filter screen is cleaned, and everything is reconnected and tested.

If you're handy and your unit has service valves, you can do this yourself with a kit from a hardware store. Follow your manufacturer's instructions, since steps vary by brand. If your unit was installed without service valves, have them added. It makes every future flush much easier.

How Often?

In Tampa Bay's hard water, plan on descaling about once a year. Homes with very hard water or heavy hot water use may need it more often. Homes with a water softener can usually go longer. Check your manual too. Many manufacturers specify regular maintenance, and skipping it can matter for warranty coverage.

Other Maintenance

• Clean the inlet filter. A small screen where cold water enters the unit catches sediment. Clean it when you descale, or anytime flow drops.
• Keep vents clear on gas units. Check that nothing is blocking the intake or exhaust, like plants, debris or nests.
• Watch for leaks at the connections under the unit.
• Keep outdoor units clear of sprinkler spray and landscaping.

Thinking About Going Tankless?

If you're comparing options, our post on tank vs. tankless water heaters covers cost, sizing and what your gas line or electrical panel needs. Tank water heaters need care too. See how to flush a tank water heater.

Tankless Water Heater Help

Believe Plumbing installs and services gas and electric tankless water heaters across Tampa Bay, including Tampa, Westchase, Carrollwood and St. Petersburg. See our water heater services or contact us for a free estimate.