Rinnai Code 63: Combustion Fan Error

Quick Answer

Rinnai Code 63 indicates a combustion fan fault, meaning the blower that draws air into the burner is not operating correctly. The fan must reach a specific RPM before the ignition sequence can begin. Common causes include a blocked fan intake (lint, insect nest, debris), a failing fan motor that cannot reach speed, a faulty fan speed sensor (Hall sensor), and loose wiring to the fan assembly. A blocked intake at the air inlet or vent is the most common and easiest fix. The fan motor assembly typically costs $80 to $150 if replacement is needed. Code 63 differs from Code 61 in that 63 often indicates a sensor or speed issue while 61 indicates full motor failure.

RinnaiWaterheaterSeverity: highDifficulty: intermediate70% DIY Success

Time to Fix

30–120 min

Difficulty

intermediate

Parts Cost

$30 – $150

Tools Needed

Screwdriver set, Multimeter

Wrong code?

Not seeing 63 on your display?

Select what your appliance is actually doing and we'll take you to the right guide.

combustion airflow fault

NavienE110

What Does the 63 Code Mean?

Combustion fan not reaching required speed or fan sensor fault. Check the air intake for blockage first, then the fan motor and speed sensor.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Fan air intake blocked by lint, debris, or insect nest40%

Combustion fan motor failing and unable to reach required RPM24%

Fan speed sensor (Hall effect sensor) reporting incorrect data14%

Partial vent obstruction causing fan to work against backpressure12%

Loose or corroded wiring connector to fan assembly10%

Symptoms You May Notice

Code 63 on controller display
No hot water, unit shuts down immediately after demand
Audible fan noise that sounds labored or slower than normal
Fan starts then stops before ignition sequence completes
No fan sound at all when demand is triggered

Can you reset a Rinnai waterheater to clear the 63 code?

After clearing a blockage or repairing a wiring connection, press the power button off and on to reset Code 63. If the fan motor or sensor was replaced, reset power at the circuit breaker for 30 seconds before restoring. The unit should proceed through its startup fan-check sequence normally.

Tools Required for Diagnosis

Screwdriver setMultimeterVacuum with brush attachment (for inlet cleaning)FlashlightElectrical contact cleaner

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

With the unit powered off

With the unit powered off, locate the air inlet on the unit housing (typically a grille or louvered panel). Inspect visually for lint accumulation, insect nests, or other debris blocking the airflow path. Use a flashlight to see into the inlet.

Cut power at the circuit breaker

Inspect all wiring connectors on the fan assembly

Restore power and trigger a hot water demand

If the fan motor tests mechanically and electrically sound but

Replacement Parts

If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.

Part Name	OEM Number	Estimated Price
Combustion Fan / Blower Motor AssemblyContact Rinnai with model number · $80–$150	Contact Rinnai with model number	$80 – $150
Fan Speed Sensor (Hall Sensor)Contact Rinnai with model number · $30–$50	Contact Rinnai with model number	$30 – $50

Verify part fitment for your Rinnai model

Repair vs. Replace Calculator

Appliance Age (Years)7 Yrs

Labor Approach

Our Verdict

REPAIR

Estimated Cost: $90 (Parts) vs $1250 (New Machine)

Frequently Asked Questions

What is the difference between Rinnai Code 63 and Code 61?

Both codes involve the combustion fan, but they indicate different failure modes. Code 63 is a fan speed or sensor error: the fan may be running but not reaching the required RPM, or the speed sensor is reporting incorrectly. Code 61 is a more definitive motor failure: the fan motor itself is not running or has burned out. Code 63 sometimes resolves with a cleared blockage; Code 61 almost always requires motor replacement.

Can I clean the Rinnai combustion fan intake myself?

Yes. Turn off power at the breaker and use a vacuum with a soft brush attachment to clear lint or debris from the air inlet grille on the unit's housing. For deeper nests inside the duct, you may need to remove the front panel to access the fan directly. This is a straightforward DIY task that does not involve gas or high-voltage components if you keep the breaker off throughout.

How often should I check the Rinnai combustion fan intake?

Annually is sufficient for most installations. If the unit is in a garage, utility room near a dryer, or an area with heavy seasonal insect activity, inspect the inlet every 6 months. Code 63 from a blocked intake is entirely preventable with routine maintenance.

My Code 63 only appears in summer. Why?

Summer is prime time for insects to build nests inside air inlets and vent caps. Wasps, hornets, and mud daubers are common culprits. They can build a nest large enough to partially block airflow in just a few days. Inspect both the air inlet on the unit and the vent termination cap on the exterior of the building. A wire mesh screen over the inlet can prevent recurrence.

Is Code 63 a DIY repair or does it need a technician?

A blocked inlet is an easy DIY fix requiring only a vacuum. Wiring connector issues are also DIY-friendly. Motor replacement is doable for experienced DIYers who are comfortable working inside electrical appliances with the power off. Fan speed sensor diagnosis and PCB-related fan faults should be handled by a technician.

Related Rinnai Waterheater Error Codes

Code: HUBRinnai Tankless Water Heater Error Codes: Complete Guide Code: 61Rinnai Code 61: Combustion Fan Motor Failure Code: 55Rinnai Code 55: Combustion Abnormality Detected Code: RESETHow to Reset a Rinnai Tankless Water Heater: All Models Guide

Same Fix on Other Brands

Navien waterheaterE110: Navien E110 Error Code: Exhaust Blockage and Venting Fault Explained

Models Known to Experience 63 Errors

This repair applies to most Rinnai waterheaters with this error code. Common model numbers include:

RUR98iN, RU199iN, RU98eN, V65iN, RL75iN, RU160iP

Last verified for technical accuracy on March 14, 2026