Rinnai Tankless Water Heater Repair & Descaling in Charleston, SC
No hot water, an error code, or water that keeps going cold? 911 Service Today repairs and maintains Rinnai tankless water heaters in Charleston, SC, and throughout the Lowcountry, including Mount Pleasant and Summerville. We diagnose the problem, explain your options, and give you an upfront estimate before any work begins.
- Same-Day Service
- Rinnai ACE Pro Certified
- Insured & Certified Local Technicians
- A Call 30 Minutes Before Our Arrival
Rinnai Tankless Water Heater Repair and Maintenance
A Rinnai tankless water heater needs a yearly descale, or flush, to remove scale (calcium and lime deposits) from the heat exchanger. Without regular service, scale builds up and the unit won’t perform as well or last as long as it should. A regular maintenance schedule helps prevent premature failure and can significantly extend its life, and with proper care a tankless heater can often outlast a traditional tank-style heater.
Like any appliance, a tankless water heater also needs occasional troubleshooting to stay in peak condition. If your water heater isn’t working as well as it used to, or if you haven’t kept up with the maintenance your manufacturer’s warranty requires, give us a call. We’ll quickly find the cause and give you a workable solution to restore your hot water.
Common Rinnai Tankless Problems We Repair
No hot water
Rinnai error codes
Fluctuating water temperature
Low hot water pressure
Banging or rumbling noises
Unexpected shutoffs
Annual Rinnai Descaling & Flush
Minerals in the water build up as scale on your heat exchanger. Over time, scale reduces efficiency, can trigger error codes, and shortens the unit’s life. Skipping maintenance can also put your manufacturer’s warranty at risk.
Signs you're due:
- Noises when the unit runs
- Reduced hot water flow
- Longer wait for hot water
- Scale or flow error codes
- Over a year since the last flush
Frequently Asked Questions
How often should a Rinnai be descaled?
Once a year is the general recommendation, more often with very hard water. Check your manual and warranty terms.
Why is my Rinnai showing an error code?
Your Rinnai displays a code when it detects a fault, and the code tells a technician where to start. Some of the most common ones:
- Code 10: blocked air supply or exhaust, often at the vent or intake
- Code 11: no ignition, meaning the unit tried to light and couldn’t
- Code 12: flame failure, meaning it lit and then lost the flame
- Code 16: overheat warning, often linked to scale or restricted flow
- LC (or 00 on some models): scale buildup, a sign it’s time to descale
Codes and meanings vary by model. Rinnai notes that codes 11 and 12 can sometimes clear by shutting off water flow for a few seconds and turning it back on. If a code returns, don’t keep resetting it. Write the code down and call (843) 789-4824, and never try to repair gas components yourself.
Why does my Rinnai water go hot, then cold, then hot again?
This is often caused by scale buildup, low water flow, or a sensor issue. A descale often helps, but if it keeps happening, a technician should inspect the unit.
Areas We Serve
- Charleston
- Summerville
- Goose Creek
- Ladson
- Hanahan
- Mount Pleasant
- Sullivan's Island
- Huger
- Wadmalaw Island
- Awendaw
- Johns Island
- James Island
- Kiawah Island
- Folly Beach
- Isle of Palms
- Daniel Island
- West Ashley
- North Charleston
- Seabrook Island
Business Hours
Monday – Friday
7:00 AM – 5:00 PM
Saturday
8:00 AM – 2:00 PM
Sunday
By appointment