Plumbing Questions? Ask a Plumber and Get Answers ASAP.
Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.
Remove and clean he screen on the cold inlet fitting on the base of the Rinnai, It's a ap on the side of the fitting. Turn the water off and open a hot (only ) faucet until the flow stops (to releive the pressure. Then unscrew and clean the screen behind the cap.