Guides
Read article Rinnai RU199iN & RXP199iN: 15 Questions Answered
Get quick answers to the 15 most common questions about the discontinued Rinnai RU199iN and its RXP199iN replacement.
Your expert Rinnai RU199iN guide.
The complete guide to the Rinnai RU199iN tankless water heater.
RU199IN is your comprehensive, independent resource for the Rinnai RU199iN gas tankless water heater. We cover everything from initial sizing and venting to error codes and maintenance.
Latest Guides & Troubleshooting
Independent, expert-reviewed articles to help you install, maintain, and descale your Rinnai condensing water heater.
Review
Read article Rinnai Tankless Water Heater Owner Reviews
Real owner feedback on Rinnai tankless water heaters, covering common praise, complaints, and what to expect as a buyer.
Buying Guide
Read article Rinnai Tankless Water Heater Tax Credits 2026
Learn how to check current federal, state, and utility rebate programs for Rinnai tankless water heaters in 2026.
Maintenance
Read article Do You Need a Softener With a Rinnai Tankless?
Find out when a water softener is worth adding alongside a Rinnai tankless water heater, based on your local water hardness.
Guides
Read article Rinnai Wi-Fi Control App: Full Feature Breakdown
See what Rinnai's Wi-Fi control app actually does, from remote temperature control to maintenance reminders and error alerts.
Maintenance
Read article Best Descaling Kits for Rinnai Tankless Heaters
Find out what to look for in a descaling kit for Rinnai tankless water heaters, from pump capacity to solution type.
Frequently Asked Questions
01What is the Rinnai RU199iN?
The Rinnai RU199iN is a high-efficiency, condensing gas tankless water heater designed for indoor installation in medium to large homes.
02What does condensing mean?
Condensing technology captures waste heat from the exhaust gas to preheat incoming cold water, achieving up to 96% thermal efficiency.
03What size gas line does the RU199iN require?
It requires a dedicated 3/4-inch gas line, though a 1/2-inch line may work under specific pressure and length constraints.
04How do I clear Rinnai error codes?
Most codes can be cleared by resolving the underlying issue (like cleaning the water filter or checking the vent) and cycling power. See our guides for code details.
05Does it support wifi control?
Yes, with the optional Control-R Wi-Fi module, you can monitor status, control recirculation, and troubleshoot via mobile app.