A tankless water heater can be an excellent investment for your home, offering endless hot water with impressive efficiency. But like any appliance you own, tankless hot water heaters can have their issues, too.

If you already own a tankless water heater or are considering installing one, here are some common issues you might encounter and how best to deal with them:

Problem #1: blocked exhaust or vents

Most tankless water heater displays show an error code to indicate that the exhaust or intake air supply is blocked – a sign that your heater is experiencing venting or combustion issues. To check the problem, identify all exhaust and intake lines, and visually inspect to ensure they are securely connected and in good condition with no holes.

Also, make sure your heater isn’t too close to any object that might block the air supply or cause a fire hazard. Check the intake and exhaust vents all the way to the exterior of your home, and inspect for things like bird or insect nests that can block the venting.

Problem #2: overloaded system

Too much simultaneous hot water demand can overload your system (i.e. multiple faucets, appliances or showers running at once.) This can force the unit to work harder to supply the hot water needed, or even completely shut down. If this happens, reduce the hot water demand by limiting simultaneous applications, and reset the water heater. Give the water heater a little time to reset and if the problem persists, consult a professional.

Problem #3: mineral deposits

Magnesium and calcium are present in some degree in most water systems and are two of the most common minerals to cause scale build-up in tankless water heaters. If not removed, mineral deposits can affect the overall performance and efficiency – and seriously shorten the life of your water heater.

Check the manufacturer’s recommendations for removing mineral build up; most recommend regular flushing and descaling. If you’re handy, you can try flushing and descaling yourself, but read the manufacturer’s recommendations carefully. If you live in an area with especially hard water and can’t stay ahead of the mineral build up, you might consider installing a water softener.

Problem #4: flame failure or no ignition

If you notice that your tankless water heater is displaying a “Flame Failure” error code or just not firing up properly, it’s likely an ignition problem. Most ignition failures are related to the gas supply/pressure or gas valve. If you think it’s an ignition problem, we recommend contacting a licensed professional for help resolving the issue.