Rinnai Rinnai RL94iN RL Series Tankless Water Heater 19 Error Fix: Electrical Grounding Issue

Error code 19 on the Rinnai Rinnai RL94iN RL Series Tankless Water Heater means: Electrical Grounding Issue. The unit has detected improper electrical grounding or current leakage. Rinnai tankless water heaters require a proper electrical ground for safe operation and for the flame sensing circuit to function correctly. The flame rod detects flame by measuring a small ionization current (microamps) flowing from the flame rod through the flame to the grounded burner. Without proper grounding, this circuit cannot function reliably. Error 19 indicates the ground fault detection circuit has sensed current leakage, a missing ground connection, or a ground-to-neutral fault. Check the power cord ground connection. Verify the electrical outlet is properly grounded using a circuit tester. Check for damaged wiring inside the unit. On installations with long gas lines, verify the gas pipe bonding. If the installation uses a GFCI outlet, the unit's normal ground current may trip the GFCI — Rinnai recommends a dedicated non-GFCI circuit for their tankless units.

The most successful fix is "Repair or Replace Faulty Ground Wiring and Check for Leakage" (hard difficulty, ~90 minutes). This fix costs nothing. HomeMD has 2 community-ranked fixes for this error.

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

Yes — the top-ranked community fix ("Repair or Replace Faulty Ground Wiring and Check for Leakage") is rated hard difficulty and takes about 90 minutes. Tools needed: T20 Torx screwdriver, Multimeter, Clamp meter, Wire strippers, Crimping tool.

DIY cost: $0. Professional repair typically costs $150-$250. Many homeowners save money by trying the top-ranked community fix first.

The Rinnai Rinnai RL94iN RL Series Tankless Water Heater has 8 other known error codes, including: 02 (Ignition Failure), 03 (Bath Fill Function Abnormality), 05 (Blocked Exhaust / Air Supply), 10 (Blocked Exhaust — Air Pressure Switch), 11 (No Ignition), and 3 more.

Error code 19 also appears on 8 other Rinnai models: Rinnai RE180iN RE Series Non-Condensing Tankless Water Heater, Rinnai RL75iN RL Series Tankless Water Heater, Rinnai RSC160iN Condensing Combi Boiler, Rinnai RU130iN Sensei Super High Efficiency Plus Tankless Water Heater, Rinnai RU199iN Sensei Super High Efficiency Plus Tankless Water Heater, Rinnai RUR199iN Sensei Recirculating Tankless Water Heater, and 2 more. The fix may vary by model, so check each model's specific page for tailored repair steps.