How To Troubleshoot A Furnace Humidifier with Constantly Running Water

A furnace humidifier is a valuable addition to any home, especially in the dry winter months. It helps maintain a comfortable indoor environment by adding humidity to the air. However, when you notice the constant sound of water running from your furnace humidifier, it can be concerning and lead to both water and electricity wastage. In this article, we will explore the steps you can take to diagnose and fix the issue of constantly running furnace humidifier water.

Diagnosing Constantly Running Furnace Humidifier Water

Furnace humidifiers typically function by wetting an air-permeable membrane, allowing the furnace fan to blow air through it, thereby adding humidity to the air. Some systems have a valve that drips water directly onto the membrane, while others utilize a reservoir to wet the membrane. Troubleshooting these two types of systems may require slightly different approaches, but both involve a solenoid valve that can be the source of the problem.

1. Check The Solenoid Wiring

If your furnace humidifier water is running continuously, even when the fan is off, it is likely due to an issue with the solenoid valve. To diagnose the problem, start by checking the solenoid’s wiring. Ensure that the solenoid valve is wired so that it is only powered when the furnace fan is on. If it is incorrectly wired, the valve will remain open, leading to constant water flow. Correct the wiring as needed to resolve this issue, but always exercise caution when working with electrical components.

2. Replace/Clean your Solenoid Valve

If the solenoid wiring is correct and the water still runs constantly, the solenoid valve itself may be clogged or malfunctioning. Debris or mineral buildup can cause the valve to stick open. To address this, you can attempt to clean the valve by flushing it with directed water pressure or gently cleaning it. If cleaning does not solve the problem, consider replacing the solenoid valve. Remember to turn off the breaker before any electrical work, and it’s advisable to seek professional help if needed.

3. Check the Reservoir Integrity

For furnace humidifiers that use a reservoir to wet the membrane, a constant water flow could be the result of a reservoir integrity issue. Examine the reservoir for cracks or failures, which can often be seen or felt when water is dripping or pooling at the bottom. If you find any issues, you can attempt to repair them using high-powered glue or tape. However, the most effective solution is to replace either the reservoir or the entire humidifier.

4. Check the Humidistat Setting

If your humidifier runs only when the fan is on but results in excessive humidity, you may be dealing with a problem related to the humidistat. The humidistat measures your home’s humidity and typically activates the humidifier when the humidity falls below a set threshold. If the humidistat setting is too high, adjust it to a lower threshold to see if that resolves the issue. If the problem persists, check the wiring connections and consider replacing the humidistat if it’s faulty.

5. Call an HVAC Professional

If any of these steps seem too complex or risky, it’s wise to seek the assistance of an HVAC professional. Hiring a professional ensures that the job is done correctly and reduces the risk of electrical hazards.

Additional Information

• How much water should drain from the furnace humidifier? According to Filters-Now, a running furnace should take 2.5 to 5 minutes to fill a quart jar from the humidifier drain, provided the home has low humidity. An idle furnace should not drain any water.
• How to turn off the water to your furnace humidifier? The location of the shut-off valve depends on the plumbing of the unit. Typically, a shut-off valve is installed at the point where the humidifier water branches off from the main house water line. If no shut-off valve is present, you may need to shut off the water to the entire house. Consider adding an accessible shut-off valve near the humidifier for future convenience.
• When should the humidifier be turned on? Use the humidifier when your home experiences very dry air, which is common in many regions during winter but can also occur in the summer in arid climates. If your home experiences excessive indoor condensation, reduce or turn off the humidifier to prevent mold and mildew issues.
• What should the furnace humidifier be set at in the summer and winter? A comfortable indoor humidity level generally ranges from 30% to 50%. However, during the winter, high humidity can lead to window condensation; in such cases, consider lowering the humidity to around 20% to 25%.

Conclusion

A constantly running furnace humidifier can be a nuisance, but with the right steps, you can diagnose and resolve the issue. Whether it’s checking the solenoid wiring, cleaning or replacing the solenoid valve, examining reservoir integrity, adjusting the humidistat settings, or seeking professional help, there are solutions available to ensure your furnace humidifier operates efficiently and effectively. Remember to prioritize safety and electrical precautions when working with these components.