Troubleshooting Tankless Water Heater Fluctuations: Why Your System Runs Hot and Cold

Follow These Tankless Water Heater Troubleshooting Steps

1. Cold Water Sandwich

An occasional occurrence known as a “cold water sandwich” can disrupt your tankless water heater’s performance. This phenomenon involves a brief burst of hot water followed by a sudden chill before returning to normal temperature. It often happens when one fixture is used immediately after another, causing a momentary delay in heating.

Solution: Installing a recirculating system or adding a small tank water heater can mitigate this issue. These solutions provide a buffer to ensure consistent water temperature, especially during peak usage times.

2. Incorrect Gas Line Size

Inadequate gas supply due to an undersized gas line can cause your tankless water heater to struggle with temperature regulation. If you’ve already extended your gas line but still experience fluctuations, it’s likely that the line size is incorrect.

Solution: Consult a professional plumber to assess and upgrade your gas line to ensure optimal performance and efficiency.

3. Improper Plumbing System Crossover

Faulty plumbing or a malfunctioning pressure balancing valve can result in cold water infiltrating the hot water line, leading to temperature fluctuations. This issue may go unnoticed until bursts of hot and cold water become apparent during use.

Solution: Adjusting the thermostat or installing a pressure-balancing valve can help regulate water temperature and prevent crossover issues.

4. Malfunctioning Flow Sensor

A malfunctioning flow sensor can disrupt the water flow rate, causing erratic temperature fluctuations in your tankless water heater. This component is responsible for relaying water flow data to the control board, which adjusts the flame accordingly.

Solution: If you suspect a faulty flow sensor, contact a professional plumber to diagnose and replace the defective part.

5. Dirty Water Filter

A clogged water filter can impede water flow and reduce system efficiency, leading to unexpected temperature changes. Sediment buildup from minerals like calcium and lime can accumulate over time, affecting water quality and heater performance.

Solution: Regularly replace the water filter every six months to maintain optimal performance and prevent mineral buildup.

6. Corroded Lines

Corroded plumbing lines can introduce contaminants into your tankless water heater, causing temperature inconsistencies and compromising system integrity.

Solution: Schedule a plumbing inspection to identify and replace corroded lines, ensuring uninterrupted hot water supply and system longevity.

7. Mineral Buildup

Hard water containing high mineral content can contribute to scale buildup in your tankless water heater, hindering heat transfer and affecting performance.

Solution: Consider installing a water softener to mitigate hard water issues and minimize mineral buildup, preserving your tankless water heater’s efficiency and longevity.

Don’t let temperature fluctuations disrupt your hot water supply! By addressing these common issues promptly, you can ensure consistent performance and optimal efficiency from your tankless water heater. Schedule a professional inspection today to identify and resolve any underlying problems.