Can you use clr to flush a tankless boiler?

Yes, CLR (Calcium, Lime, and Rust remover) can be used to flush a tankless boiler, but it should be done with caution. It's important to ensure that the product is compatible with the materials used in the boiler, as some acids can damage components. Always follow the manufacturer's guidelines for descaling and flushing procedures to avoid voiding the warranty or causing damage. Using a dedicated descaling solution designed for boilers is often recommended for optimal results.