Rinnai Code 10: No Gas Supply or Gas Valve Failure

Quick Answer

Rinnai Code 10 indicates the unit attempted to open the gas valve and begin a heating cycle but could not detect gas flow. The first thing to check is whether other gas appliances in the home are working. If a stove or furnace is also out, the issue is upstream of the water heater and requires the gas utility. If other appliances work normally, the fault is internal: either the gas shut-off valve feeding the unit is closed, gas pressure is below the unit's minimum threshold, or the gas valve solenoid has failed. Natural gas minimum supply pressure is 4 inches WC; LP minimum is 8 inches WC. Solenoid coils should measure 30 to 80 ohms.

RinnaiWaterheaterSeverity: high82% DIY Success

Time to Fix

15–60 min

Difficulty

beginner

Parts Cost

$20 – $280

Tools Needed

Multimeter, Manometer (for gas pressure verification)

Wrong code?

Not seeing 10 on your display?

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

no ignition, no gas detected

NavienE003

What Does the 10 Code Mean?

No gas supply detected when the unit tried to fire. Start with the simplest check: are other gas appliances in your home working? If yes, the issue is at or near the water heater.

Most Likely Causes

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

Gas supply valve to the unit closed or only partially open40%

Gas utility outage or service interruption in the area24%

Gas supply pressure below unit minimum (4 in WC for NG, 8 in WC for LP)14%

Gas meter undersized for the total connected load12%

Gas valve solenoid coil failure inside the unit10%

Symptoms You May Notice

Code 10 on controller display
No ignition attempts heard (clicking) when demand is made
All other gas appliances in home also not working (if utility issue)
Unit acts completely dead when hot water tap is opened
No flame during any startup attempt

Can you reset a Rinnai waterheater to clear the 10 code?

Once the gas supply has been restored or the valve opened, reset the unit by pressing the power button off then on again. If the unit had a gas supply interruption, it may take 1 to 2 minutes for gas to purge air from the supply line before ignition is successful. This is normal after a supply restoration.

Tools Required for Diagnosis

MultimeterManometer (for gas pressure verification)Gas leak detector solution or electronic leak detectorScrewdriver set

Diagnostic Checklist

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

Test whether other gas appliances in the home are working

Test whether other gas appliances in the home are working. Try lighting a gas range burner or check if the furnace fires. This takes 30 seconds and determines whether the problem is house-wide or isolated to the water heater.

Locate the gas shut-off valve on the supply pipe directly

If you have an LP (propane) system, check the tank gauge

If you have a manometer

With power off and gas closed

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
Gas Valve AssemblyContact Rinnai with model number · $150–$280	Contact Rinnai with model number	$150 – $280
Gas Pressure Regulator (LP installations)Varies by tank size · $20–$60	Varies by tank size	$20 – $60

Verify part fitment for your Rinnai model

Repair vs. Replace Calculator

Appliance Age (Years)7 Yrs

Labor Approach

Our Verdict

REPAIR

Estimated Cost: $150 (Parts) vs $1250 (New Machine)

Frequently Asked Questions

Is Rinnai Code 10 dangerous?

Code 10 itself means the unit detected a gas supply problem and shut down safely. That is protective behavior, not a dangerous failure. The unit is not firing, so there is no combustion risk. However, if you smell gas at the unit or supply lines, treat that as a separate safety issue: leave the area and call your gas utility immediately.

My gas stove works but my Rinnai still shows Code 10. What now?

With other gas appliances confirmed working, the issue is localized. The most likely causes in order are: the shut-off valve on the unit's supply line is partially closed, the gas pressure to the unit specifically is marginal due to undersized supply pipe or regulator, or the gas valve solenoid inside the unit has failed. Work through steps 2 through 5 above in order.

How long does it take for a Rinnai to fire after gas supply is restored?

After a gas interruption, air enters the supply line between the main valve and the unit. It typically takes 1 to 3 restart attempts before enough air is purged and gas reaches the burner for ignition. This means you may see Code 11 (ignition failure) once or twice before the unit successfully lights. This is normal and not a sign of a separate fault.

Can Code 10 be caused by a software glitch?

Rarely, a PCB fault can cause the control board to misread the gas valve state and trigger Code 10 even when gas supply is fine. This is the least common cause and should only be suspected after gas supply has been verified as fully normal, the solenoid tests within spec, and the error persists. PCB diagnosis requires a technician.

What gas pressure does a Rinnai water heater require?

Rinnai tankless heaters require a natural gas supply pressure of 4 to 10.5 inches water column (WC) at the unit under firing conditions. For LP (propane) installations, the required range is 8 to 14 inches WC. Pressure below the minimum under load, not just at rest, will cause Code 10 or Code 11. A manometer connected to the gas test port while the unit fires is the only accurate way to verify operating pressure.

Related Rinnai Waterheater Error Codes

Code: HUBRinnai Tankless Water Heater Error Codes: Complete Guide Code: 11Rinnai Code 11: No Ignition Fix for RU and V Series Tankless Heaters Code: 12Rinnai Code 12: Flame Failure During Operation Code: RESETHow to Reset a Rinnai Tankless Water Heater: All Models Guide

Same Fix on Other Brands

Navien waterheaterE003: Navien E003 Error Code: Ignition Failure Fix for NPE and NCB Series

Models Known to Experience 10 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