Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater 12 Error Fix: Flame Failure — Flame Lost During Operation

The burner ignited successfully but the flame was lost during operation. This differs from Code 11 in that initial ignition DID occur. Causes include: unstable or low gas supply pressure (can occur during high-demand periods when other gas appliances are running simultaneously), wind blowing into the vent termination and extinguishing the flame, a partially blocked exhaust vent, a dirty or degraded flame rod (carbon buildup reducing flame detection sensitivity), or an intermittent gas solenoid valve failure. If this code occurs primarily during windy conditions, check the vent termination for wind exposure and install a wind-resistant termination fitting. Clean or replace the flame rod.

warning2 fixes available✨ Free fix available

Quick Answer

Error 12 on the Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater means: Flame Failure — Flame Lost During Operation. The top-ranked community fix is “Replace the Flame Rod and Inspect Exhaust Venting” (medium difficulty, ~45 min, DIY cost: $15-$25). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · water heater

Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.

When to Call a Professional

While many water heater repairs can be done safely at home, consider hiring a qualified technician if:

The repair involves electrical wiring, gas lines, or refrigerant
You've tried the top-ranked fix and the error persists
You smell gas, see sparking, or notice water leaking
The repair requires specialized tools you don't have
Your appliance is still under manufacturer warranty

Average professional repair cost for this issue: $120-$180.

Other Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater Error Codes

False Flame Detection

2 fixes

Abnormal Combustion — Blocked Vent

2 fixes

Ignition Failure — No Flame Detected

2 fixes

Thermal Fuse Activated — Overheat Safety

2 fixes

Overheating — Outgoing Water Too Hot

2 fixes

Abnormal Temperature Rise — Low Water Flow

2 fixes

Condensate Drain / Vent Blockage

2 fixes

Outgoing Water Temperature Sensor Failure

2 fixes

People Also Ask About Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater Error 12

What does error code 12 mean on a Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater?

Error code 12 on the Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater means: Flame Failure — Flame Lost During Operation. The burner ignited successfully but the flame was lost during operation. This differs from Code 11 in that initial ignition DID occur. Causes include: unstable or low gas supply pressure (can occur during high-demand periods when other gas appliances are running simultaneously), wind blowing into the vent termination and extinguishing the flame, a partially blocked exhaust vent, a dirty or degraded flame rod (carbon buildup reducing flame detection sensitivity), or an intermittent gas solenoid valve failure. If this code occurs primarily during windy conditions, check the vent termination for wind exposure and install a wind-resistant termination fitting. Clean or replace the flame rod.

How do I fix error code 12 on my Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater?

The most successful fix is "Replace the Flame Rod and Inspect Exhaust Venting" (medium difficulty, ~45 minutes). Estimated DIY cost: $15-$25. HomeMD has 2 community-ranked fixes for this error.

Is error code 12 on a Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater serious?

This error is rated warning severity. It is generally not urgent and can often be resolved with a simple DIY fix.

Can I fix Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater error 12 myself?

Yes — the top-ranked community fix ("Replace the Flame Rod and Inspect Exhaust Venting") is rated medium difficulty and takes about 45 minutes. Tools needed: T20 Torx screwdriver, Multimeter.

How much does it cost to repair Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater error 12?

DIY cost: $15-$25. Professional repair typically costs $120-$180. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater have?

The Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater has 8 other known error codes, including: 05 (False Flame Detection), 10 (Abnormal Combustion — Blocked Vent), 11 (Ignition Failure — No Flame Detected), 14 (Thermal Fuse Activated — Overheat Safety), 16 (Overheating — Outgoing Water Too Hot), and 3 more.

What other error codes does the Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater have?

The Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater has 8 other known error codes:

05 — False Flame Detection (2 fixes)
10 — Abnormal Combustion — Blocked Vent (2 fixes)
11 — Ignition Failure — No Flame Detected (2 fixes)
14 — Thermal Fuse Activated — Overheat Safety (2 fixes)
16 — Overheating — Outgoing Water Too Hot (2 fixes)
24 — Abnormal Temperature Rise — Low Water Flow (2 fixes)
29 — Condensate Drain / Vent Blockage (2 fixes)
32 — Outgoing Water Temperature Sensor Failure (2 fixes)

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