ERM Plumbing & Heating

October 7, 2022

Tankless water heaters, despite their rare use and utilization, are not immune to malfunctions and problems. Regardless, it is crucial to know about specific situations and how to address them quickly and efficiently. 

Read on as we address seven tankless water heater problems and how to fix them.

When the Water Heater Fails to Run

It is extremely inconvenient if your tankless water heater fails to heat the water, as this is its sole purpose. It is also possible that the problem is related to the fuel (or lack thereof). Fuel is required for the water heater. 

Check the fuse associated with the circuit breaker first. If this is not the case, make sure the heater is turned on and has gas.

When the Water is Discolored and Has Odor

If you notice an unusual odor or a change in the color of your water, it is possible that something is accumulating inside your water heater. A tankless water heater's functionality can be restored by flushing out any excess magnesium and calcium. 

To prevent buildup, the water heater should be flushed once every six months. Minerals in hard water can be removed with vinegar or a descaling solution.

When "No Ignition" is Displayed

"No ignition" on the display can mean that the gas and water valves have either been turned off or have not been turned off. Either of these prevents the ignition from running properly. 

If your tankless water heater is not working correctly, check the ignition pack as well as the propane tank. If this is not the case, make sure that all of the valves are open so that the gas can ignite the flame.

When “Flame Failure” Happens

The term "flame failure" refers to the fact that the heater's flame does not remain lit. It is possible that the issue was caused by clogged ventilation or closed valves. 

For this situation, the gas, propane, and water valves must be checked in the same way that the "no ignition" switch must be checked. Examine the heater's vents to ensure that nothing is blocking them.

When the Air Flow Is Obstructed

Tankless water heating systems require clean air ventilation while in use. If the ventilation system of a tankless water heater is obstructed in any way, it will not function properly.

Turn on the pipe that discharges exhaust. Next, clean the vents on the inside and outside of the vehicle. Look for holes in pipes. Check that the system was properly installed. Installations that are placed too close to one another may cause a blockage.

When the Temperature Fluctuates

The reason for the water cycling between hot and cold and hot while the faucet is turned on is relatively straightforward. When some of the hot water that was previously prepared is still in your possession, you will receive the hot water that was not used. 

For this, give it time and wait. The tankless water heater in your home must reheat itself in order to provide additional hot water. The water should be usable after it has been heated for the required amount of time.

When the System is Overburdened

When a system is subjected to excessive strain, the temperature of the water may fluctuate on a regular basis. The system is at capacity if your tankless water heater is not working properly or is not producing enough hot water. Because of this issue, the water heater may shut down unexpectedly. 

For this, reset the water heater and wait for the hot water to return by turning on one of the sink's faucets. If this problem persists on a daily basis, you should consider upgrading to a more robust system or replacing the heater.


It is important to remember that maintaining a comfortable temperature in the tank of a conventional water heater requires a significant amount of energy. As such, you must act quickly and swiftly in repairing water heater problems, such as those stated above.

With correct and timely solutions, you have the potential to save money while also avoiding costly repairs in the future. This way, you can also use your system more efficiently and extend its lifespan.

Are you looking for hot water tanks in Calgary? ERM Plumbing & Heating is a team of professionals who are dedicated to giving you plumbing and heating solutions. Contact us today!

Latest Blogs

Prevent Frozen Pipes And Drain Clogs

Tips to Prevent Frozen Pipes and Drain Clogs

Read More

Factors causing furnace malfunction

Common Factors That Can Cause Furnace Malfunction

Read More

Tips To Winterise Your Plumbing

Tips To Safeguard Your Plumbing From Freezing

Read More