Water Heater Repair: Common Problems With A Tankless Water Heater

What water heater have you installed at your Knoxville, TN, home? From conventional water heaters, hybrid water heaters, heat pump water heaters, and solar-powered water heaters to tankless water heaters, there are many water heater variants that you can rely on for heated water. However, a tankless water heater is the most energy-efficient of all. It heats water on demand, meaning it only uses energy when necessary. Since the water heater doesn’t feature a tank, it also saves you space

However, regardless of how convenient and advanced they are, tankless water heaters aren’t immune to various problems. They also experience normal wear and tear, especially with aging. No electrical appliance doesn’t experience various issues and faults in its lifetime. However, tankless heaters have their issues, unlike conventional water heaters. However, you can put the issues at bay with routine maintenance and inspections by a water heater repair technician.

Tankless water heaters are remarkable for their energy efficiency, space-saving, and water conservation.   All these features can only mean one thing; saving money in the long run. However, various tankless water heater issues might sometimes undermine these benefits. Hence you must understand the most common issues that affect tankless water heaters and take the measures to avert them by enlisting the help of a water heater repair professional. Below are some of the common problems that befall a tankless water heater;


Each tankless water heater usually has a defined flow rate capacity. This should give you a great idea of how much-heated water the unit can produce within a given duration. Further, this can form a great pointer to the number of outlets that can be opened simultaneously. Going over the tankless water heater’s flow capacity could mean that you are overloading the system.

This can cause various issues that might prompt a need for water heater repair. Overloading the tankless water heater is a common problem, especially if you have a young family or guests coming over. Unfortunately, some homeowners don’t realize that there are limitations to the number of simultaneous hot water outlets when it comes to a tankless water heater.

When a tankless water heater gets overloaded, you may notice that some people at your home aren’t getting enough heated water while others are enjoying their showers and hot baths. The water heater might sometimes entirely shut down because of a system overload. Understanding the rated flow capacity of a tankless water heater is the only way to ensure that you don’t overload the unit.

Hence, please read the manual with the tankless water heater to understand its capacity and the number of appliances that can simultaneously draw hot water from the unit. If this issue becomes persistent, then it is best to call a water heater repair professional to inspect your water heater. The water heater might be too small to cater to your family’s needs. In that case, the technician will recommend upgrading it or installing a tankless water heater to compensate for the deficit.

Ignition or Flame Failure

Does your tankless water heater sufficiently heat the water? If it doesn’t, the reason may be that the flame doesn’t hold or even ignite. A gas line or electrical issue may cause this. Regardless you’ll need to enlist the help of a water heater repair technician because the water heater will not be able to heat your water. The professional will begin by checking whether the propane tank has enough gas or if you have a gas supply. If you haven’t paid the bill, your gas utility provider might cut the supply to your Knoxville, TN, home.

If the professional ascertains that the gas supply is alright, the technician will check to see that the gas and water valves are fully open. If they aren’t, the professional opens them fully to allow a complete gas flow into the water heater. If all these are in vain, the water heater repair professional will inspect other parts such as regulators for failure and the undersized gas lines that might pose a risk at your home.

Cold Water Sandwich

Have you ever heard of the cold-water sandwich? If your home has frequent back-to-back showers, then it is most likely that you might have experienced the sensation. Cold water sandwich refers to the phenomenon in which when a person is done showering, and another one enters the shower immediately; they get hot water immediately though for a few seconds. They then experience a cold shower for a few seconds as the water heats up in the pipes, and later, hot water begins to flow.

So, why does this happen? It arises since the water in a tankless water heater doesn’t get heated when no outlet is open. However, there is some hot water that remains in the pipes. The heated water flows for the first few seconds, followed by the incoming cold water. It is at this time when the tankless water heater works to heat the water that you will later receive from a hot water faucet or shower. However, this shouldn’t take too long.

Since this effect is a part of the tankless water heater design, it isn’t too much of an issue. Although a tankless water heater is at times like for the rate at which it heats the water, being that the heated water isn’t stored makes it pretty much impossible for your tankless water heater to deliver heated water immediately. If the cold spells last for long, you should have a water heater repair technician inspect the tankless water heater. There might be other underlying issues.

Sediment or Mineral Buildup

The piping and water heater may become susceptible to partial or complete blockage caused by an accumulation of minerals or sediments. Plumbing systems with iron components and pipes might start rusting, resulting in a buildup of iron sediments. Additionally, if your Knoxville, TN, home receives hard water from your water utility provider, you might see minerals such as magnesium and calcium result in limescale buildup.

The sediments and minerals may become stuck in place, resulting in a gradual buildup. The accumulation narrows the passage through which the water passes. This might affect the water temperature and pressure, making it potentially unsafe. A water heater repair professional can flush the water heater to remove the sediments.

Reputable Plumbing Professionals

Have you experienced either of the above issues with your tankless water heater? Ensure that they are assessed by a professional to ensure that the unit delivers heated water into your home. Do you need a water heater repair service for your tankless unit? Call our technicians at My Professional Plumber.

Photo By Koldunov Alexey at Shutterstock