Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater 65 Error Fix: Water Flow Control / Flow Sensor Failure

The water flow sensor or flow control servo motor is not operating correctly. The flow sensor detects when a hot water tap is opened (triggering the ignition sequence) and measures the flow rate. On some RTGH models, a flow control servo adjusts water flow rate to achieve the desired temperature. If the flow sensor fails, the unit may not detect water flow (no ignition when a tap is opened) or may fire erratically. Check the flow sensor wiring for loose connections. Clean the flow sensor — mineral deposits can coat the sensor element and interfere with readings. Test the servo motor for proper movement. Replace components as needed.

warning2 fixes available

Quick Answer

Error 65 on the Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater means: Water Flow Control / Flow Sensor Failure. The top-ranked community fix is “Test and Replace Flow Sensor or Flow Control Servo Motor” (medium difficulty, ~60 min, DIY cost: $0-$15). 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: $200-$350.

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

Flame Failure — Flame Lost During Operation

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

People Also Ask About Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater Error 65

What does error code 65 mean on a Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater?

Error code 65 on the Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater means: Water Flow Control / Flow Sensor Failure. The water flow sensor or flow control servo motor is not operating correctly. The flow sensor detects when a hot water tap is opened (triggering the ignition sequence) and measures the flow rate. On some RTGH models, a flow control servo adjusts water flow rate to achieve the desired temperature. If the flow sensor fails, the unit may not detect water flow (no ignition when a tap is opened) or may fire erratically. Check the flow sensor wiring for loose connections. Clean the flow sensor — mineral deposits can coat the sensor element and interfere with readings. Test the servo motor for proper movement. Replace components as needed.

How do I fix error code 65 on my Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater?

The most successful fix is "Test and Replace Flow Sensor or Flow Control Servo Motor" (medium difficulty, ~60 minutes). Estimated DIY cost: $0-$15. HomeMD has 2 community-ranked fixes for this error.

Is error code 65 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 65 myself?

Yes — the top-ranked community fix ("Test and Replace Flow Sensor or Flow Control Servo Motor") is rated medium difficulty and takes about 60 minutes. Tools needed: T20 Torx screwdriver, Multimeter, Needle-nose pliers.

How much does it cost to repair Rheem Rheem RTGH-95DVLN Prestige 9.5 GPM Condensing Tankless Gas Water Heater error 65?

DIY cost: $0-$15. Professional repair typically costs $200-$350. 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), 12 (Flame Failure — Flame Lost During Operation), 14 (Thermal Fuse Activated — Overheat Safety), 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)
12 — Flame Failure — Flame Lost During Operation (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)

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