Tankless water heaters are efficient, compact, and long-lasting—but only if you take care of them. If you forget regular upkeep, you risk lower performance, higher energy bills, and expensive repairs.

Here’s the good news: maintaining a tankless system doesn’t take much. With a few simple steps each year, you can avoid problems and keep your water heater running like it should.

This guide breaks down clear, practical tankless water heater maintenance tips you can use right now.

1. Flush the System Once a Year

Hard water is a common problem in many areas. Over time, minerals like calcium and magnesium build up inside your tankless water heater. This scale reduces efficiency and puts stress on your system.

Flushing clears out the buildup and keeps water flowing the way it should.

Here’s how it works:

• Turn off the power and water supply.
• Attach a hose and pump to the service valves.
• Use white vinegar (or a descaling solution) to flush the system for about 45 minutes.
• Drain, rinse, and reconnect everything.

If you’re not comfortable doing this yourself, call a professional. At Dr. Kool HVAC, we handle flushing as part of our regular service visits.

Tip: Set a reminder to flush your system once a year. If your water is especially hard, every 6 months is better.

2. Clean the Water Filter

Tankless water heaters have a small filter that traps debris from your water supply. It’s easy to forget about, but if it clogs, your system won’t work efficiently—and might even shut down.

To clean it:

• Shut off the water to the unit.
• Locate the filter (usually near the cold-water inlet).
• Remove it, rinse it under water, and reinsert it.

This only takes a few minutes but helps prevent costly problems down the road.

3. Inspect the Air Intake Filter

Your tankless unit may have an air filter—especially if it’s a gas model. This keeps dust and debris out of the combustion chamber.

If the filter gets blocked, airflow drops and the unit can overheat or shut off.

Check your owner’s manual to find the filter. Remove it, clean it gently, and put it back. Do this at least once a year—or more often if your home has pets or dust buildup.

4. Check for Error Codes

Modern tankless systems display error codes if something isn’t working right. You’ll usually find these on a small digital screen.

If you see a code, don’t ignore it. Look it up in your manual or call a technician. Catching issues early can save you from bigger problems later.

Some common codes relate to:

• Ignition failure
• Water pressure problems
• Blocked vents
• Scale buildup

If you’re not sure what the code means, get in touch with a local HVAC expert like Dr. Kool HVAC. We’ll figure it out for you.

5. Watch for Water Pressure Changes

Your tankless system needs the right water pressure to run smoothly. If it’s too low, the heater won’t fire up. If it’s too high, it could damage internal parts.

Install a pressure gauge near your main water line if you don’t have one. Ideal pressure is usually between 50–80 PSI.

If you notice sudden changes in water pressure, check for leaks or clogs. Or call a professional to check your plumbing.

6. Keep the Area Around the Unit Clear

Whether your tankless water heater is mounted indoors or outdoors, make sure the area around it is clean and open.

Don’t store items too close. Make sure vents aren’t blocked. This helps air flow properly and reduces fire risk.

If your unit is outside, protect it from extreme cold in winter. Use insulation or a cover to prevent freezing.

7. Schedule Professional Maintenance

Some tasks—like flushing and filter cleaning—are DIY-friendly. But a full inspection by a licensed HVAC technician is still a good idea once a year.

A pro will:

• Test gas pressure and burner performance
• Check electrical connections
• Inspect venting and airflow
• Clean internal components
• Make sure your system is up to code

Regular professional tankless water heater maintenance helps your unit last longer and run better. It also keeps your warranty valid in many cases.

8. Pay Attention to Strange Noises or Smells

Your water heater should be nearly silent during operation. If you hear banging, rattling, or clicking, something’s off.

Also watch for:

• Rotten egg smells (could mean a gas leak)
• Burnt odors (might mean overheating)
• Water that smells metallic or discolored

Any of these signs means it’s time to shut off the system and call a technician.

Need to schedule your annual tankless water heater maintenance?

Your tankless water heater works hard every day. Give it a little attention, and it’ll reward you with years of reliable hot water and lower energy bills.

These tankless water heater maintenance tips help you:

• Avoid system failures
• Improve efficiency
• Extend the life of your unit
• Catch problems before they get expensive

If you want professional help, we’re ready. At Dr. Kool HVAC, we service all major brands and offer honest, clear pricing for maintenance and repairs.

Contact us today to book your service. We'll help you keep your system in top shape—no hassle, no upselling, just clean and reliable HVAC care.