Menu

Call This Friday to Get $50 Off Any service over $500

Call This Friday to Get

$

50

Off
Any service over $500

Need an Emergency Plumber? Call

323-400-6362

Financing Available (Subject to Credit Approval)

Book Online
Why Is My Tankless Water Heater Running Hot and Cold?
4.9 RATING
4.6 RATING
4.6 RATING
Why Is My Tankless Water Heater Running Hot and Cold?
Oct 24,2024

Why Is My Tankless Water Heater Running Hot and Cold?

Tankless water heaters are energy efficient and provide endless hot water on demand. However, you may experience an issue where the water temperature fluctuates, running hot and cold unexpectedly. This is a frustrating scenario, especially when you’re in the middle of a shower or washing dishes. If you notice this problem with your tankless unit, Rooter Man is the go-to plumbing service for repairs. Let’s explore the common reasons this happens, and solutions.

blogdetail-image

Water Flow Rate Issues

One of the most common reasons for temperature fluctuations in a tankless water heater is a water flow rate problem. Tankless systems don’t require a high flow rate to activate and maintain the heating process. If the flow rate decreases below the limit, the heater may shut off temporarily, causing the water to go cold. To resolve this, ensure you’re using enough hot water to maintain a steady flow. In case of a recurrence, hire a professional for water heater repair services, ensuring minimum flow settings without risking further damage.

Cold Water Sandwich Effect

The “cold water sandwich” is a common occurrence that happens when hot water that’s stored in the pipes is used first, followed by a brief surge of cold water before the heater catches up to deliver more hot water. This can cause fluctuating temperatures, especially during short-duration uses like hand washing. You can minimize this by allowing the hot water to run for a bit before use, especially when using fixtures for short periods. It is also advisable to hire a plumber to install a recirculation pump, ensuring you maintain a more consistent supply of hot water.

Mineral Build-up

Hard water contains high levels of minerals like calcium and magnesium, which can cause scaling inside your tankless system. These mineral deposits accumulate and restrict water flow, causing uneven heating or temperature drops. The buildup can interfere with the heating elements, resulting in malfunctions and premature water heater replacement emergencies.

The best way to prevent this is through regular maintenance by a plumbing service provider. Professionals can descale your water heater or install a water softener to minimize mineral accumulation.

Gas Supply Problems

If you have a gas-powered tankless water heater, inconsistent gas supply can lead to hot and cold water fluctuations. Check if your heater isn’t getting enough gas and call a plumber to maintain a steady temperature. This could be because of low gas pressure, a malfunctioning gas valve, or an issue with the gas line. If you prefer a more hands-off approach, contact a professional to check your gas supply and system. Gas issues can be dangerous, so this isn’t something to troubleshoot on your own.

Incorrect Heater Size

Sometimes, the issue is the tankless water heater size. A unit that’s too small for your household’s needs may require more frequent maintenance calls, as it tries to keep up with multiple appliances or fixtures that demand hot water simultaneously. To fix this, you might need to schedule a complete water heater replacement or limit the number of hot water appliances used at once. If you upgrade your tankless unit and experience the same issue, consult a plumbing repair service to inspect and address underlying issues quickly.

Experiencing hot and cold fluctuations with a tankless water heater is frustrating. However, the underlying causes are often easy to identify and resolve. Whether it’s a problem with the water flow rate, mineral buildup, or an undersized heater, a reputable plumbing repair service can address the root issue and restore consistent water temperatures. Contact us at Rooter Man and schedule exceptional water heater repair services to ensure your unit operates efficiently and reliably.

Latest Blog

The 4 Stages of Septic Tank Installation Mar 26,2025
The 4 Stages of Septic Tank Installation

Home improvement projects are usually stressful and rigorous, especially if you do not know the extent of the project. Rooter Man Plumbing is a reputable septic company in Acton,…

Read More
Plumbing Tips for New Homeowners Mar 26,2025
Plumbing Tips for New Homeowners

Nothing is more thrilling than owning your own home. Whether you built it from the ground up or purchased an existing building, making the plumbing system cater to your needs…

Read More
Reasons Why Pipe Damage Can Happen Mar 19,2025
Reasons Why Pipe Damage Can Happen

Plumbing lines are the unsung heroes of residential and commercial buildings, silently carrying water and removing waste. While plumbing systems can run for years without showing signs of deterioration, underlying…

Read More
How to Prepare Your Septic System for Long Vacations or Seasonal Absences? Mar 19,2025
How to Prepare Your Septic System for Long Vacations or Seasonal Absences?

Are you planning a family vacation? Before embarking on a trip to your favorite destinations, there are several things you need to check off your list. While most people focus…

Read More