Rinnai SS Error Code: Service soon (flush heat exchanger)
Updated October 2026 · Sourced from Rinnai documentation
A time-based service reminder set at installation. The manual says the heat exchanger should be flushed to prevent damage and hard water must be treated.
Is it safe to keep running? Usually yes. Contact a trained and qualified professional to flush the heat exchanger. A professional can reset the SS code per the manual.
SS at a glance
| Code / how it shows | Meaning | Applies to |
|---|---|---|
| SS SS (shown on the controller) | Service soon (flush heat exchanger) | SENSEI N Series residential condensing: RU199i, RU180i, RU160i, RU130i (indoor) and RU199e, RU180e, RU160e, RU130e (outdoor) |
Check this first
Only steps a homeowner can do safely. Do not open electrical panels or the burner area.
- The unit can keep running. The manual says to contact your local service provider to flush and service it (section 4.12.2).
🛑 Stop and call a licensed pro if
- Contact a trained and qualified professional to flush the heat exchanger. A professional can reset the SS code per the manual.
- You smell gas. Leave the house, do not touch switches, and call your gas utility from outside.
- Codes for flame failure, overheating, venting or the control board that return after one reset.
- Water leaking from the heater, the relief valve discharging, or scorching around the burner area.
- A carbon monoxide alarm sounds. Get everyone outside and call 911 or the fire department.
Safe first steps for any Rinnai code
- Write down the exact code shown on the controller or the number of status light flashes.
- Turn the water heater power off and back on (or press the reset button the manual describes) once. If the code comes back, stop resetting.
- Make sure the gas supply valve to the heater is open and other gas appliances in the home are working.
- Make sure the cold water supply valve is fully open and hot water taps are not partly closed.
- Look at the outside vent terminal for snow, ice, leaves or anything blocking it (look only).
Source: Rinnai SENSEI N Series Residential Installation and Operation Manual (100000467), 5.6 Diagnostic Codes, p.75 and p.62. Codes are series-specific, so your unit's own manual is the final word. Reviewed October 2026.
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