Descaling Tankless Water Heaters: A Guide to Using CLR and Alternatives
Tankless water heaters, also known as on-demand water heaters, provide hot water only when you need it, offering energy efficiency and space savings. However, like all appliances that handle water, they are susceptible to mineral buildup, particularly in areas with hard water. This buildup, primarily calcium and magnesium deposits, reduces efficiency and can even damage the unit. Regular cleaning is essential to maintain optimal performance and prolong the lifespan of your tankless water heater. While various cleaning methods exist, many homeowners consider using CLR (Calcium, Lime, Rust remover) as a convenient and effective solution for descaling, but it’s crucial to understand the proper procedure and potential risks before using CLR.
Understanding the Need for Descaling
Mineral deposits accumulate over time, forming scale on the internal components of the tankless water heater. This scale acts as an insulator, hindering heat transfer and forcing the unit to work harder to heat the water. The consequences of neglecting descaling include:
- Reduced energy efficiency, leading to higher utility bills.
- Lower hot water output and fluctuating water temperatures.
- Increased risk of component failure and costly repairs.
- Decreased lifespan of the water heater.
Is CLR the Right Choice? Considerations and Precautions
Important Note: While CLR is often used, many manufacturers recommend against its use due to its potentially corrosive nature. Always consult your tankless water heater’s manual before using any descaling solution, including CLR. Using a solution not recommended by the manufacturer could void your warranty. If your manual does allow CLR, proceed with extreme caution.
Before proceeding with CLR, consider the following:
- Material Compatibility: CLR can be corrosive to certain metals, particularly those found in older plumbing systems. Ensure your system is compatible.
- Concentration: Using an overly concentrated solution can damage the unit. Always dilute CLR according to the product label and the tankless water heater’s manual (if applicable).
- Flushing Thoroughness: Residual CLR can corrode internal components and contaminate your water supply. Thorough flushing is absolutely critical.
Alternatives to CLR
A safer and often recommended alternative is white vinegar. It’s a natural descaler and less likely to cause damage. Dedicated descaling solutions formulated specifically for tankless water heaters are also available and often preferred.
The CLR Cleaning Process (If Approved by Manufacturer)
- Turn off the power and gas supply to the tankless water heater.
- Isolate the unit: Locate the service valves (usually blue and red) on the cold water inlet and hot water outlet. Close both valves.
- Drain the unit: Attach hoses to the service ports and direct them to a bucket or drain. Open the drain valves to release any remaining water.
- Prepare the CLR solution: Mix CLR with water according to the product label and the manufacturer’s instructions (if available). A common ratio is 1:6 (CLR to water), but always verify.
- Circulate the solution: Use a submersible pump to circulate the CLR solution through the unit for the recommended time (typically 1-2 hours). Ensure the solution is circulating continuously.
- Flush Thoroughly: This is the most important step. Disconnect the hoses and open the cold water inlet valve to flush the unit with clean water for at least 20-30 minutes. Continue flushing until the water runs clear and there is no trace of CLR odor.
- Reconnect and Restart: Close the drain valves, disconnect the hoses, open the service valves, and restore power and gas supply to the unit.
Properly maintaining your tankless water heater ensures its longevity and efficiency. When considering cleaning methods, remember to prioritize safety and manufacturer recommendations. When using CLR, due diligence is paramount, and alternatives should be considered for optimal care.
