Understanding Two Common Tankless Gas Water Heater Error Codes

Posted on: 21 October 2020

Most tankless water heaters (and many other modern appliances) now include a display to alert you of potential trouble. Like the check engine light in your car, this display alerts you when the heater's control board detects one or more faults. Depending on your water heater model, this display may show text messages or error codes that you'll need to cross-reference with the manual.

The specific numeric codes may vary between manufacturers, but two of the most common underlying causes are ignition failure and flame failure. Keep reading to learn what these codes mean and the approaches a technician may take to repair them.

Ignition Failure

Most gas appliances include fail-safes to detect proper ignition. If the burner doesn't ignite, the fail-safe stops gas flow to prevent a dangerous leak. Your heater can't keep your home's water warm if the burner doesn't ignite, so you'll usually notice a problem before you discover an error code. Unfortunately, ignition failure can be the result of several potential issues.

Since your burner can't stop without gas, a good first step is to double-check that you haven't closed the gas valve and that your utility company hasn't stopped service. If you still have gas, then there may be an issue with the electric igniter, a problem with the burner, or even an issue with airflow. Combustion requires fresh air and a way to eliminate byproducts, so a clogged intake or flue can prevent ignition.

A good rule of thumb is to check for additional error codes that might shed some light on the problem. If you can't find any further information, you'll likely need a professional to help diagnose and correct the problem. In most cases, it's a good idea to rely on a plumber to deal with ignition issues since they may require checking or disconnecting the gas line.

Flame Failure

A flame failure message indicates that your heater has successfully ignited its burner but cannot maintain a flame. Unlike an ignition failure, you may still have some hot water with a flame failure condition. In this case, the heater may run for a while and shut down, causing you to lose hot water suddenly even under relatively low-demand conditions.

Flame failures are commonly the result of air intake or exhaust issues. There may be sufficient air to ignite the burner but insufficient airflow to ensure it continues running for a full duty cycle. A blocked exhaust flue can also trigger the water heater's built-in safety and cause the burner to shut off. In most cases, a technician should be able to discover and resolve issues for you quickly.

Tankless gas water heaters are safe, reliable, and offer considerable advantages over conventional storage heaters. Learning some of the most common issues with these units will help you know when to call in professional help to restore your home's hot water. Contact a repair company for more information about tankless water heaters.