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Rinnai · Tankless water heater

19 Electrical grounding / DC circuit short

High severity Non-SENSEIRH180 hybridSENSEI RX/CXSENSEI

What the control is telling you

Code 19 showing right after water flow starts (no visible flame) indicates an electrical short in a component on the DC circuit.

Applies to: SENSEI Series; SENSEI RX/CX Series; Non-SENSEI Series

Likely causes

  • Shorted wiring harness
  • Shorted water flow control valve
  • Shorted bypass valve
  • Short in another DC-circuit component

Test and repair steps

  1. Confirm the code appears immediately when water flow begins with no flame visible in the burner box.
  2. Disconnect DC-circuit components (harnesses, water flow control, bypass valve, etc.) one at a time and try to fire the unit after each.
  3. If the unit cycles on three times after a component is unplugged, that component holds the short; repair or replace it.

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Source: Rinnai Troubleshooting TWH Diagnostic Codes (100000652), p.31. Summarized in our own words; check the original manual for your model.

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For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.