5 Common Problems With Tankless Water Heater & How to Fix Them

5 Common Tankless Water Heater Problems & How to Fix Them

5 Common Problems Tankless Water Heater  & How to Fix Them

For homeowners leaping into the world of tankless water heaters, it’s like stepping into the comfort of a hot shower that never runs cold. But what happens when the luxury of endless hot water starts to falter, and your visions of a consistent, energy-efficient oasis are disrupted by the complexities of the system? Don’t worry, this guide will help you fix problems with tankless water heaters carefully and accurately. We will share how to fix 5 common problems with tankless water heaters. Follow our easy tips to keep your heater working well and avoid cold showers.

1. Mineral Build-Up and Scale Formation

Imagine your tankless water heater as a brave knight on a quest to keep your water hot, slaying every cold molecule in its path. A hero? Absolutely. But even the bravest knight accumulates battle scars over time. In the realm of tankless water heaters, mineral build-up is one of these common problems—secretly reducing the weapon’s effectiveness.

Symptoms: Reduced water flow, hot spots, and a strange ticking noise within your system can all point to mineral deposits.
Resolution: The first line of defense is a good water softener, but for existing scales, a professional descaling or a vinegar flush can work wonders.

The Culprit Unmasked

The culprit here is hard water, loaded with minerals like calcium and magnesium—your knight’s arch-nemesis. When heated, these minerals have a penchant for bonding together, forming a white film that lessens the efficiency of your heating element.

2. Ignition Failure

Next on our list of common problems,  ignition failure is akin to the lights going out in a dark hallway—your warm path to blissful showers is suddenly in jeopardy.

Symptoms: A lack of hot water, an error code on your heater, or a red light signaling trouble could indicate an ignition issue.

Resolution: Sometimes, it’s a simple fix—check for a blown fuse, a tripped circuit breaker, or that the gas is on. Otherwise, the burner assembly or the ignition elements might need cleaning or replacement.

The Mysterious Disappearing Flame

For your water heater to do its job, a small burner inside the unit must ignite each time water is called for. Imagine a lone candle in the wind; if it doesn’t come on or stay lit, you’re left in the cold.

Searching for a Spark

Begin your quest by ensuring that there’s no obstacle between your heater and the gas supply. Dust, lint, or even a tiny Webber dwelling within the burner assembly can interfere with the flame. A gentle cleaning might rekindle your warmth.

3. Ventilation ProblemsWenbrooke is your source for Heating, Air Conditioning, Electrical, and Plumbing repairs in Frederick, MD.

The silence of a tankless water heater is golden, but sometimes, it might be deafening. Hinting at a ventilation issue, the heater’s cry echoes a complex struggle for the flow of air, affecting the combustion process.

Symptoms: There’s a backdraft in the vent, the water heater is consistently loud, or the unit keeps shutting off.

Resolution: Inspect the venting system for blockages, a collapsed pipe, or an inadequate slope. Ensuring that the vent is not shared with any other appliance also helps maintain proper airflow.

The Battle for Oxygen

Your tankless water heater craves oxygen like a knight craves victory, and its venting system is the portal to this life-giving element. Any obstruction in the vent is akin to leading him into battle without a sword.

Clearing the Path

Check to see if the outside vent is clear from any debris, including bird nests (yes, really). A mirror might help inspect the vents’ interior. If the problem is not outside the castle walls, a professional should investigate further.

4. Thermo… What Now?

The flow of hot water is a delicate balance—much like brewing a perfect cup of coffee. When the temperature sensors in a tankless water heater go awry, precision goes out the window, and your showers become a gamble.

Symptoms: The water temperature fluctuates wildly, or your water is too hot or too cold, constantly.

Resolution: Test the water heater for consistent flow across a wide range of temperatures. If you notice drastic changes, the temperature sensor probably needs calibration or replacement.

The Sensitive Souls

Tankless water heaters are equipped with sensors—usually thermistors—that ensure the water is heated to your set temperature. Without these sensors’ keen judgment, you might be dancing between arctic blasts and volcanic eruptions in the shower.

Gauging Accuracy

Calibration involves accessing the sensor and adjusting it according to the manufacturer’s specifications. But be warned—this is delicate work, and precision is key. If the thought of fiddling with your heater’s innards makes you queasy, a professional’s deft touch is the best choice.

5. Overwork and Overheat

Every hero has a breaking point, and in the case of tankless water heaters, overworking can lead to overheating.  Next on our list of common problems with tankless water heaters is overworking. With no tank to store hot water, a relentless demand can push your heater past its limits, risking damage and potentially, failure.

Symptoms: The unit keeps shutting off due to overheating, or the high-temperature shutdown is activated frequently.

Resolution: Evaluate your water usage and heater capacity. A professional can help size your water heater correctly, and install a larger unit if needed.

The Endurance Test

Think of your tankless water heater as an endurance runner in a marathon. Asking it to sprint the first five miles might bring you closer to the finish line quicker, but the probability of collapse is far higher.

Finding Equilibrium

Understanding your household’s hot water needs is crucial. Basic questions about residents, bathrooms, and hot water use can help determine if your unit is the right size. If your tankless water heater doesn’t provide enough hot water, you might need a bigger one. Upgrading to a larger model can give you more hot water.


In the ever-evolving world of home technologies, tankless water heaters stand as a shining beacon of progress. New technologies bring new responsibilities. Homeowners must now maintain and care for these innovations as part of their duties.  This will help keep your system running efficiently. It will also ensure that your system provides warmth and comfort as intended. Don’t let these common problems with tankless water heaters catch you by surprise.