Short answer
Rinnai Infinity continuous flow water heaters flash a two-digit error code on the display or controller. The most common are 11 (no ignition or gas supply), 12 (flame failure or earth leakage) and 10 (not enough combustion air). LC means scale build-up in the heat exchanger. Rinnai says codes 14 and above need a service call.
Which models this covers
The codes below are from Rinnai UK's installation and user manual for the Infinity 26e/26i, Infinity 32e/32i, HD50e/HD50i and HD70e/HD70i. These are common in London restaurants, gyms and hotels, often installed in banks of several units.
Codes 11 and 12 on commercial sites
On multi-heater installations, codes 11 and 12 often mean the gas supply cannot keep up when every unit fires together: undersized pipework, a small meter, or a regulator that drops pressure under load. We measure working pressure at each heater with all units running to find the cause.
LC scale code
LC shows that scale is building up in the heat exchanger. London's hard water makes this common. The heat exchanger needs descaling, and on busy sites we recommend water treatment and a regular service plan.
Before you reset
A single reset after a power cut or a known one-off event is reasonable. Repeated resets are not: many commercial controls count resets and lock out further (for example a 'too many resets' code), and resetting a flame or gas valve fault over and over can mask a dangerous condition. If a lockout returns, isolate the appliance and call a Gas Safe registered engineer with the relevant commercial competence.
Rinnai Infinity error codes
| Code | Meaning | What to check |
|---|---|---|
| 03 | Power interruption during operation (water will not flow when power returned) | Turn off all hot water taps and circulating pumps; press On/Off twice |
| 10 | Not enough combustion air | Check for blockages around air intake or exhaust; check combustion fan |
| 11 | No ignition / gas supply | Check gas valves, gas supply and sparker unit |
| 12 | Flame failure / earth leakage | Check gas valves and gas supply, flame rod, earth wire lead and remote control |
| 14 | High flame safety device | Service call |
| 16 | Over temperature warning | Service call |
| 32 | Outgoing water temperature sensor faulty | Service call |
| 33 | Heat exchanger outlet sensor faulty | Service call |
| 34 | Combustion air temperature sensor faulty | Service call |
| 52 | Gas modulating valve faulty | Service call |
| 61 | Combustion fan failure | Service call |
| 65 | Water flow control faulty (does not stop flow properly) | Service call |
| 71 | Micro-processor failure | Service call |
| 72 | Flame rod circuit error | Service call |
| LC (00) | Scale build-up in heat exchanger | Service call (display alternates with temperature and beeps; resets on power off/on) |
Source: Rinnai UK Installation and User Manual — Infinity / HD range (Error Messages, p.14). Codes and meanings can differ between versions and control software — always check the manual for your exact appliance.
Figures are typical for UK natural gas. The current edition of the relevant IGEM standard and the manufacturer's instructions always take precedence on site.
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