3 Common Issues With Tankless Water Heating Systems

Water Heater Hose — Seattle, WA — Quality Plumbing

Tankless hot water systems are often highly efficient and compact, a huge plus for most homeowners who want to upgrade their old heating systems. Because they only heat water when you need it, tankless heaters can save you a lot of money from your monthly utility bills.

However, just like with any other home appliance, tankless water heaters can develop problems with time. Some issues are easy to identify and fix, but others require a lot more technical expertise.

But before you go tankless, know what to expect with your new investment to help keep your system in top working condition. Discover three common problems with most tankless water heating systems and how best to address them.

1. Cold Water Sandwich

A cold-water sandwich is when water temperature fluctuates when using the shower or faucet in your home. Here, the water is hot when you first turn on the tap, becoming cold then slowly getting warmer. You’re likely to experience a cold-water sandwich if people in your home take back-to-back showers.

Unlike traditional tanks, tankless water heating systems don’t have any reserves to store hot water. Most tankless heaters will manage to give you constant hot water when only one faucet runs. With two running taps, you often use hot water faster than the tank can heat the incoming cold water. As a result, the tankless water heater may take a while to deliver hot water.

If you can’t avoid taking back-to-back showers, you’ll need to wait for all the cold water to run from the taps before you start getting a constant supply of hot water.

2. Acute System Overload

Tankless water heaters have a flow rate limit, a useful parameter when determining how much water the tank can heat for simultaneous use. Going above the flow rate capacity could mean problems with your heating system.

For example, if you use multiple faucets at the same time, the tankless heating system might get overwhelmed. Here, the net flow rate is higher than its rated capacity limit, which leads to a system overload.

Overloading the unit is often likely to cause system failure, where your tankless water heater cannot produce enough hot water, and in some cases, none at all. Fortunately, you can get around the flow rate limit by:

  • Upgrading your system’s capacity. You could replace your tankless heating unit with a larger model with a higher flow rate limit.
  • Installing a second heating unit. By adding a second tankless heater, your hot water demands are often sufficiently met. A dual water heating setup ensures efficient load sharing between the two tankless heaters, giving you enough hot water for simultaneous use.

A professional plumbing expert should draft you a reliable estimate of the capacity of tank you would need, whether you replace your unit or bring in an additional one.

3. Exhaust Vent Blockage

Tankless heating systems need a constant supply of fresh air while heating cold water. Without an active air supply, the heating system will be less efficient since hot exhaust gas remains inside the system.

Trapped exhaust air often results in poor heat maintenance and carbon monoxide poisoning from the heating system. Luckily, tankless water heaters have a notification display to help you identify exhaust vent problems.

Diagnosing the root cause of most vent issues can be difficult for the average homeowner. A professional plumber knows where to look when examining your tankless heater. They will first check for anything that could block the vents, including rodent and wasp nests. Your plumber could also perform standard tests to check for holes and loose pipes that could restrict proper airflow into the unit.

Identifying such problems early saves both your time and money. At Quality Plumbing, we take pride in ensuring that your new tankless heating system stays in good condition and serves all your heating demands effectively. Feel free to contact us today for more information on tankless water heaters.