Rinnai Boiler Equipment & Error Codes

Platform & Control Notes

I-Series condensing combi and solo boilers use E:### codes. Normal system pressure on these runs ~17–26 psi. (Rinnai tankless water heaters use a different code set — ask us if that's what you have.)

Model Families & Platforms

• I-Series Condensing Combi (i060c, i090c, i120c)
• I-Series Condensing Solo (i060s, i090s, i120s)

Diagnostic Characteristics & Common Service Topics

Rinnai boilers utilize specific display codes and safety lockouts to protect the heat exchanger, combustion system, and hydronic loop. Everyday issues like pressure loss, flame sensing errors, or circulator faults trigger specific responses depending on the controller generation.

Sample Fault Code Summaries from Vault Records

Code	Meaning	Action Required
E:100	Air supply or exhaust blockage / condensate trap full.	Safely check that outdoor intake/exhaust terminations are clear of snow, ice, leaves, or debris. If clearing them doesn't resolve it, or the condensate trap needs service, call a licensed pro.
E:110	No ignition — burner failed to light.	Verify the manual gas valve is open and (propane) the tank isn't empty, then one reset. If it won't light or recurs, stop and call a pro.
E:120	Flame failure — flame was established but then lost.	Confirm gas is fully on, then one reset. Flame-sensing/combustion faults need a tech with a combustion analyzer — if it doesn't clear, call a pro.
E:140	Heat exchanger overheat.	Check that pressure reads in the normal 17–26 psi band. Overheat usually means a flow problem — call a licensed pro. Don't keep resetting an overheating boiler.
E:190	Electrical grounding fault.	Not a homeowner repair. Confirm the boiler is on a properly grounded, correctly wired outlet (no extension cords/adapters). Call a licensed pro or electrician.
E:430	High or low water pressure in the heating system.	Read the gauge — normal cold range is ~17–26 psi. Adding water or checking the expansion tank should be done by your installer. Repeated low pressure usually means a leak — call a pro.
E:443	Low Water Cut Off (LWCO) activated.	An LWCO trip means the boiler shut down for safety. Don't fire it dry. Check for visible leaks and call a licensed pro to find the cause and refill/bleed correctly.
E:540	High exhaust (flue gas) temperature.	A combustion/heat-exchanger issue — not a homeowner repair. Call a licensed pro to inspect the heat exchanger, venting, and combustion.

Related Symptom & Diagnostic Guides

Sources & Documentation

• error-codes.json — https://media.rinnai.us/salsify_asset/s-c1e4cb84-0b9d-4c3b-9c5b-9749d8dd9b10/800000114-I-Series%20Condensing%20Combi%20Boiler%20User%20Manual.pdf