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Rinnai · Boiler

150 Venturi control fault

High severity I-Series Plus 150K and smallerI-Series Plus 175K and higher

What the control is telling you

The PC Board can't communicate with the venturi, or the venturi isn't moving (exercising) correctly.

Applies to: I-Series Plus boilers — 150K BTU and smaller and 175K BTU and higher (Combi and Solo)

Likely causes

  • Loose, damaged or broken gas valve/solenoid wiring
  • Reed switch on gas valve mispositioned or front/back sensors swapped
  • Moisture in electrical connections
  • Wrong orifice (175K+) or wrong A0 gas type
  • Faulty gas valve/venturi assembly

Test and repair steps

  1. Cycle main power, then call for heat or hot water to see if the code clears.
  2. Inspect gas valve and solenoid harnesses for loose, damaged or broken connections.
  3. Confirm the reed switch on the front of the gas valve is positioned correctly (see Code 220) and the front and back reed sensors aren't swapped.
  4. Check all harnesses for moisture; dry connectors thoroughly, find the water source and repair.
  5. 175K and higher confirm the correct gas orifice is fitted in the gas valve, groove side out (grey = propane, black = natural gas, white = natural gas high altitude above 2000 ft).
  6. Confirm Parameter A0 matches the supplied gas (A = Natural Gas, b = Propane).
  7. Verify venturi pin voltages and resistances at the PC Board (CN11) against the Electrical Diagnostics tables in the source manual (p.10).
  8. For a related high outgoing temperature, also follow the Code 161 procedure.
  9. Replace the gas valve assembly if the fault remains.

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Source: Rinnai Troubleshooting I-Series Plus Boiler Diagnostic Codes (800000375), p.10. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

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.