Safety first: why pressure relief valves are a must-have for tankless water heaters

Tankless water heaters have gained immense popularity in recent years due to their energy efficiency and space-saving design. However, one crucial aspect that often raises questions is the necessity of a pressure relief valve (PRV) for these appliances. In this comprehensive blog post, we will delve into the importance of PRVs for tankless water heaters, exploring the specific reasons why they are essential, the potential risks of not having one, and the proper installation and maintenance practices.

Understanding the Role of Pressure Relief Valves

A pressure relief valve is a safety device designed to prevent excessive water pressure from building up in a water system. When the water pressure exceeds a predetermined limit, the PRV opens automatically, releasing excess water and reducing the pressure. This prevents potentially catastrophic damage to the water heater and other plumbing components.

Why Tankless Water Heaters Need Pressure Relief Valves

Unlike traditional tank-type water heaters that have a large storage capacity, tankless water heaters heat water on demand. This means that water is constantly flowing through the unit, creating a higher potential for pressure buildup. Without a PRV, the pressure could exceed safe limits, leading to:

• Burst Pipes and Leaks: Excessive pressure can weaken and eventually burst pipes, leading to leaks that can cause extensive water damage.
• Damage to the Water Heater: High pressure can strain the internal components of the water heater, reducing its lifespan and potentially causing it to fail prematurely.
• Scalding Injuries: If the PRV fails or is not installed properly, hot water could escape from the unit, potentially causing severe scalding injuries.

Potential Risks of Not Having a Pressure Relief Valve

The absence of a PRV in a tankless water heater can pose significant risks, including:

• Catastrophic Damage: Without a PRV, excessive pressure could build up and cause the water heater to explode, resulting in severe property damage and potential injuries.
• Warranty Voidance: Most manufacturers require the installation of a PRV as a condition of the warranty. Failure to install one could void the warranty, leaving you responsible for any repair or replacement costs.

Proper Installation and Maintenance of Pressure Relief Valves

To ensure the proper functioning of a pressure relief valve, it is crucial to install it correctly and maintain it regularly:

• Installation: The PRV should be installed on the cold water inlet line, as close to the water heater as possible. It should be facing downward and have a discharge pipe that directs the released water to a safe location.
• Maintenance: Inspect the PRV annually to ensure it is not clogged or obstructed. Periodically, lift the lever on the valve to manually test its operation. If water does not discharge, the valve may need to be replaced.

Other Safety Measures for Tankless Water Heaters

In addition to a PRV, several other safety measures can enhance the safe operation of tankless water heaters:

• Expansion Tank: An expansion tank absorbs excess water volume when the water heats up, preventing pressure spikes.
• Temperature Limiting Valve: This valve limits the maximum water temperature, reducing the risk of scalding.
• Ground Fault Circuit Interrupter (GFCI): A GFCI protects against electrical shocks by interrupting power if an electrical fault is detected.

Summary: The Indispensability of Pressure Relief Valves

In conclusion, pressure relief valves play a crucial role in ensuring the safety and longevity of tankless water heaters. They prevent excessive pressure buildup, which can lead to catastrophic damage and injuries. Proper installation and regular maintenance of the PRV are essential to maintain its functionality and protect your water heater and your home. By understanding the importance of PRVs and implementing the necessary safety measures, you can enjoy the benefits of tankless water heating with peace of mind.

Questions We Hear a Lot

Q: Is it legal to operate a tankless water heater without a pressure relief valve?
A: No, most building codes require the installation of a PRV on all water heaters, including tankless models.

Q: How often should I replace the pressure relief valve?
A: It is recommended to replace the PRV every 5-10 years or as recommended by the manufacturer.

Q: Can I install a pressure relief valve on my own?
A: While it is possible to install a PRV yourself, it is highly recommended to hire a licensed plumber to ensure proper installation and avoid potential safety hazards.