Rinnai i-Series+ LC — Scale Buildup in Heat Exchanger
LC
Scale Buildup in Heat Exchanger. Flush the DHW plate heat exchanger, and the LC code will reset automatically when scaling is removed. The table classifies it as Combi Only.
Applies to
This domestic hot water fault code is displayed by the i-Series+ front-panel control on i-Series+ combi models (IP175199C, IP199199C), as documented in Installation and Operation Manual — i-Series+ 175K and 199K combi boilers (hosted on the Rinnai Canada IP175199C product page). Codes can differ between controller generations, so always check the manual that matches your unit.
- Rinnai i-Series+ Combi
- Rinnai IP060160C
- Rinnai IP090099C
- Rinnai IP090199C
- Rinnai IP120199C
- Rinnai IP150199C
- Rinnai IP175199C
- Rinnai IP199199C
Controller: i-Series+ front-panel control. Source manual: see sources (2025).
Why a code is not a diagnosis
A DHW code involves the hot-water side: sensors, flow, the mixing/bypass valve or the DHW heat exchanger. It does not say whether the fix is a sensor, a valve or a flush.
Safe things to observe
- Note the code and whether the problem follows a hot-water draw or appears at all times.
Do not
- Do not open the appliance to test DHW components yourself.
How professional service helps
- A technician tests the DHW sensors, flow switch and valve circuits, and cleans the DHW path where the manual directs.
- Combustion and safety devices are verified with an analyser and the manufacturer's procedure after any repair.
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Parts and service
Parts commonly involved
These parts appear in the documented text for this alert. A code reports a condition, not a failed part — a technician confirms the cause by testing before anything is replaced.
DHW plate heat exchanger
The DHW plate heat exchanger is the stainless-steel block inside a combi boiler that transfers heat from the boiler's water to the domestic hot water…
What a technician checks →
Service for this alert
- Gas Boiler Repair
Licensed gas technicians from ROMA Heating & Cooling diagnose and repair residential and light-commercial gas boilers across…
- Gas Boiler Replacement
ROMA replaces old, failed or inefficient gas boilers in Greater Vancouver, handling removal, venting and gas-supply changes,…
Every boiler part explained — what it does, how it fails and what a technician checks.
Documented for Rinnai i-Series+ Combi.
Frequently asked questions
Can I clear this code myself?
Clearing a code without fixing its cause usually just brings it back. Note the code, check the safe items on this page, then call a licensed technician. If your appliance manual describes a user reset for this exact code and it stays away, no call may be needed.
Boiler locked out? Call with the alert text ready.
The brand, model and this alert are passed along when you request service online, so the technician arrives prepared.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
- Installation and Operation Manual — i-Series+ 175K and 199K combi boilers (hosted on the Rinnai Canada IP175199C product page) · accessed September 7, 2026
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.