Rinnai Tankless Water Heater: Weak or missing flame signal (flame rod checks)

Weak or missing flame signal (flame rod checks) on a Rinnai tankless water heater: Electrical checks for a flame rod circuit that reads low, from the Electrical Diagnostics page.

Homeowner with a tankless water heater problem? Call (647) 657-2977 or book a service call — licensed technicians across Vaughan and the GTA.

Applies to: SENSEI RX/CX (RX199i, RX180i, RX160i, RX130i, CX199i, CX160i, RXP199i, RXP160i, CXP199i, CXP160i)

Common causes of weak or missing flame signal (flame rod checks)

• Carbon or damage on the flame rod
• Loose or damaged flame rod wiring
• Old flame rod gasket reused

How to fix weak or missing flame signal (flame rod checks): step by step

1. With the heater running, measure AC volts between the flame rod and ground; a healthy rod reads roughly 5 to 150 VAC.
2. Put the meter on the microamp range in series with the rod; 1 microamp or more is a good flame circuit.
3. If the signal is low, remove the rod, inspect it for carbon or damage and clean or replace it.
4. Always fit a new flame rod gasket after the rod has been removed.

If the unit shows an error code, look it up: Rinnai Tankless Water Heater codes

Models

Non-SENSEI

C199eC199iR50LSiR63LSe2R75LSeR75LSiR94LSeR94LSiR98LSeR98LSe-ASMER98LSiR98LSi-ASMERC80eRC80iRC98eRC98iRE140eRE140iRE160eRE160iRE180eRE180iRE199eRE199iREP160eREP160iREP199eREP199iRL75eRL75e(A)RL75iRL75i(A)RL94eRL94iRLX94iRU80eRU80iRU90eRU98eRU98iRUC80iRUC90iRUC98iRUCS65iRUCS75iRUR98eRUR98iRUS65eRUS75eV53DeV53eV65eV65iV75eV75iV94eV94iV94Xi

SENSEI

CU160eCU160iCU199eCU199iRSC160eRSC160iRSC199eRSC199iRU130eRU130iRU160eRU160iRU180eRU180iRU199eRU199iRUR160eRUR160iRUR199eRUR199i

SENSEI RX/CX

CX160iCX199iCXP160iCXP199iRX130iRX160iRX180iRX199iRXP160iRXP199i

RH180 hybrid

RH180