Rinnai Boiler Error Codes: 110, 430 and 180 by Model

By Ray Bennett · Updated 17 October 2026 · 7 min read · Checked against the sources at the end

Rinnai Boiler Error Codes: 110, 430 and 180 by Model

Short answer

Rinnai's original I-Series manuals call 110 no ignition and 430 high or low heating water pressure. I-Series Plus adds 180 for a gas valve adjustment limit. M-Series uses another list: 501 means no flame detected, while 110 is a supply sensor fault.

Rinnai boiler error codes need the model beside them: Rinnai uses 110 for no ignition on the original I-Series, but for a supply temperature sensor fault on the M-Series. Choosing the right list saves you chasing the wrong problem.

The tables below cover the original I-Series combi and Solo boilers and the M-Series combi and Solo boilers. Code 180 has a separate I-Series Plus note. If your appliance only heats tap water, use the Rinnai tankless water heater code guide instead.

Before you start

What to carry: a torch, a pen and your boiler paperwork. Keep the cabinet closed for these checks.

Gas or electric? Rinnai’s manuals here cover gas boilers, with electrical controls. They are not lists for electric boilers or Rinnai room heaters.

Renting? Send the fault details to the person who arranges your heating repairs before booking work yourself.

Deal with gas, overheating or a CO alarm first.
Rinnai’s I-Series Plus user manual says that if overheating occurs or the gas will not shut off, leave the pump’s electrical supply connected and shut off the gas outside the appliance. Its original I-Series and M-Series manuals also direct you to shut the manual gas valve for overheating. Do not use a power reset as the response to an overheating boiler.

If you smell gas, Rinnai says not to light an appliance, touch an electrical switch or use a phone inside. Leave and call the gas supplier from outside, and follow their instructions. If you cannot reach them, call the fire department.

For a carbon monoxide alarm, CPSC says to go outside without searching for the source, call emergency services, and count everyone to check that nobody is missing. Stay out until responders allow you back. If an appliance caused the alarm, CPSC says not to use it until trained personnel have serviced it.

Rinnai reserves installation and service for qualified people. Leave gas pressure, electrodes, wiring, internal drains and safety devices to the repairer. Rinnai says not to use a boiler if any part has been under water. Call a licensed professional immediately to inspect it and replace affected controls.

Start with the model and the whole display

Keep the boiler family, full display and affected service together. The cabinet and screen are simplified illustrations.

Check 1No parts needed to identify the boiler

Choose the matching Rinnai list

Write down the full code, any words beside it and whether room heating, hot taps or both have stopped. Use an accessible model label or your installation paperwork.

Rinnai’s original I-Series manuals cover i060C, i090C and i120C combis, plus i060S, i090S, i120S and i150S Solo boilers. Its M-Series manuals cover M060C, M090C, M120C and M160C, and the corresponding M060S, M090S, M120S and M160S Solo models.

Do not drop a zero from the screen. If you searched for Rinnai boiler error code 11, the original I-Series chart below uses 110 for no ignition. A genuine two digit 11 needs the appliance’s own list.

Original I-Series boiler codes

Rinnai’s original Combi manual 800000111 and Solo manual 800000112 give these meanings. CH means central heating; DHW means domestic hot water for taps. The investigation column describes service work, not instructions to dismantle the boiler.

I-Series code	Rinnai’s meaning	What needs checking
100	Air or exhaust blockage, or full condensate trap	Venting, condensate drainage, air filter and fan
110	No ignition	Gas availability, ignition, flame sensing and venting
120	Flame failure	Gas supply, flame rod wiring and combustion conditions
140	Heat exchanger overheat	Overheat switch, pump, heating circuit and possible scale blockage
170	Venturi blockage	Venturi, silencer, condensate drain and vent connection
250	Accessory condensate pump fault	Pump reservoir, operation and connections
353 / 363 / 393	Supply / return / outdoor temperature sensor	The named sensor, wiring and applicable settings
400	Pressure sensor	Sensor wiring and voltage
430	High or low water pressure	Actual heating pressure, leaks, fill and relief valve
443	Low water cutoff	Cutoff device and its electrical circuit
540 / 610	High exhaust temperature / combustion fan	Exhaust sensing and venting / fan and harness
LC, combi only	Scale buildup in heat exchanger	DHW plate heat exchanger flush and related flow or sensor checks

Check 2Supply information first; testing may need a service visit

110 or 120: separate fuel supply from an internal fault

Rinnai starts its original I-Series 110 and 120 checks with gas availability, including fuel in a propane tank. A known utility interruption or empty tank is useful information for the repairer. Do not open a valve that someone deliberately closed for a fault or gas work.

The same chart goes on to ignition components, flame rod wiring, grounding, gas pressure and venting. It does not say that every 110 needs a new igniter. Leave gas line bleeding and electrical measurements to the technician.

Check 3Pressure diagnosis; repair work depends on the cause

430: report the pressure before adding water

Rinnai defines 430 as high or low water pressure in both original I-Series manuals. That makes the displayed pressure worth reporting before anyone assumes the boiler needs filling.

Its service chart calls for checking heating system leaks, the water fill and the pressure relief valve. The technician’s correction depends on which side of the pressure range is wrong. The separate boiler pressure guide explains the gauge and symptoms in more detail.

Keep 400 separate: Rinnai labels that a pressure sensor fault and calls for wiring and voltage checks. The two numbers lead to different investigations.

What code 180 means on I-Series Plus

In its I-Series Plus 150K BTU and smaller user manual, 800000192, Rinnai calls 180 Gas Valve Adjustment Limit. That entry belongs to the Plus series covered by this manual, not the original I-Series tables above.

Rinnai tells the owner to contact a qualified service provider whenever a diagnostic code shuts down those Plus boilers. Do not try to alter the gas valve or installer parameters to clear 180.

The same three digits point to different parts on the original I-Series and M-Series. The Plus 180 entry comes from its own user manual.

M-Series boiler codes

For the M-Series models named above, Rinnai’s Combi and Solo charts use the following meanings. A blocking code can correct automatically; a fault needs resetting and/or correction before normal operation resumes.

M-Series display	Meaning in Rinnai’s chart
101	Overheat
102	Pressure sensor circuit damaged
103 to 107	Flow checks failed
108 / 109	Supply water pressure below minimum / above maximum
110 / 112 / 114	Supply / return / outdoor sensor circuit damaged
1P4	Filling needed: pressure below the warning level
201, combi only	Domestic hot water sensor circuit damaged
304	Too many resets
501 / 504	No flame detected / flame lost during burner operation
502	Flame detected with the gas valve closed
612	Fan speed too high or too low
3P9	Scheduled maintenance reminder

Resetting and checking the result

Check 4No reset part to buy; a returning fault needs diagnosis

Use the reset for your control after the cause is addressed

For the original I-Series combi, Rinnai says to press the blinking Central Heating or Domestic Hot Water button. The Solo uses the blinking Central Heating or Indirect Tank button. Some codes cannot be reset this way and need service assistance.

For the M-Series, Rinnai shows RESET, followed by OK to confirm or ESC to cancel. Its 304 entry says more than five reset presses in 15 minutes causes that fault; leave the button alone for 15 minutes if 304 appears.

After restarting as described above, check whether the rooms warm up or the taps get hot, and whether the same code returns. Give that result to the repairer. For a boiler that stays cold without a listed fault, continue with boiler not working.

What each one takes

Finding	Work involved
Original I-Series 110 or 120	Fuel supply confirmation, then ignition and combustion testing
Original I-Series 430	Heating water pressure and leak checks; fill or relief valve work if testing calls for it
I-Series Plus 180	A qualified service provider handling a gas valve adjustment limit
M-Series 110	Supply sensor circuit diagnosis
M-Series 3P9	Scheduled maintenance and its reminder setting

Questions people ask

Does a Rinnai boiler have the same code list as a tankless heater?

No, they are separate lists. Rinnai’s original I-Series boiler uses three digit 110 for no ignition, and the tankless heater codes are covered in the separate guide linked above.

Is M-Series 501 a bad gas valve?

Rinnai defines 501 as no flame detected, without identifying one failed part in that entry. Give the technician the starting sequence and any known fuel interruption, rather than ordering a valve from the number alone.

Can I reset original I-Series 170 immediately?

Rinnai specifically says to check for a blocked condensate drain and correct vent connection before resetting 170. Those checks belong with the venturi and silencer investigation in its service chart.

Why does the original I-Series combi show FFF in its history?

Rinnai describes FFF as a history marker entered after maintenance or service. It is not a diagnosis of a broken component.

Where is the original I-Series fault history?

Rinnai says to hold Domestic Hot Water on the combi, or Indirect Tank on the Solo, for two seconds, then press Up while still holding it. The last nine maintenance codes appear in turn. Repeat that button sequence to leave history.

The other boiler guides: boiler keeps turning off, circulator pump problems, and boiler pressure.

Sources: Rinnai I-Series Combi Installation and Operation Manual 800000111, pp. 6, 10, 100 to 103; I-Series Solo manual 800000112, pp. 1, 99 to 102; M-Series Combi manual 800000063(01), pp. 1, 83 to 85; M-Series Solo manual 800000065(01), pp. 1, 65 to 67; I-Series Plus 150K BTU and Smaller User Manual 800000192, pp. 2, 5, 25; CPSC Carbon Monoxide Questions and Answers.