No hot water from Ruud gas tank water heater; pilot will not light or stay lit, no electronic error code present.

Safety first: If you smell gas, do not attempt to light the pilot. Evacuate and call your gas supplier.

• Step 1 – Verify gas supply: Ensure the manual gas shutoff valve to the heater is fully open and other gas appliances work.
• Step 2 – Follow lighting instructions: Use the lighting instructions on the heater label. Hold the pilot button long enough (typically 30–60 seconds) after the pilot lights to heat the thermocouple/thermopile.
• Step 3 – Clean pilot: If the pilot flame is weak or yellow, turn gas OFF, remove the burner assembly, and blow compressed air through the pilot orifice to clear debris.
• Step 4 – Replace thermocouple/thermopile: If the pilot lights but will not stay lit, replace the OEM Ruud thermocouple (older models) or thermopile (newer FVIR models). Disconnect from the gas control, remove from the burner bracket, and install the new sensor.

If the pilot still will not stay lit, the gas control valve may be defective and should be replaced by a technician.