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Rinnai Error Code 430: High or low system water pressure (Combi Boiler)

Updated · by Aurora Star Tech Inc.

Rinnai error code 430 on a combi boiler means: High or low system water pressure. It is also called Rinnai diagnostic code 430.

High severityCombi BoilerI-Series Plus 150K and smaller · I-Series Plus 175K and higher

Homeowner? What Rinnai code 430 means for you

Call a technician Your combi boiler is reporting: High or low system water pressure. The combi boiler has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.

Safe things you can check yourself

  • Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
  • Make sure the unit has power: its on/off switch (often looks like a light switch near the unit) is ON and the breaker in the electrical panel is not tripped.
  • Look at the pressure gauge on the boiler. If it reads much lower than usual or near zero, or water is leaking, call a technician.
  • Outside, make sure the intake and exhaust pipes or vent cap are not blocked by snow, ice, leaves or a nest.
  • Check that the boiler gas valve is open (handle in line with the pipe).
  • Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.
  • If only hot water is missing, check that the hot water tap is open far enough to start the heater.

Call (647) 657-2977Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Rinnai error code 430 mean?

System pressure is outside the normal 13–87 psi band. Between 7 and 13 psi the boiler runs derated (warning); at 7 psi or less, or 87 psi and above, it shuts down.

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

Common causes of Rinnai code 430

  • Low system fill pressure or leaks in the CH system
  • Undersized, undercharged or waterlogged expansion tank
  • Faulty or leaking pressure relief valve

A technician checks these and 3 other possible causes on site before replacing any part.

Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Rinnai models that use code 430

IP060160CIP090099CIP090160CIP090199CIP120199CIP150199CIP175199CIP199199C

Other Rinnai Combi Boiler codes

CodeMeaning
341DHW inlet thermistor fault
353CH supply thermistor fault
363CH return thermistor fault
380Exhaust thermistor fault
393Outdoor temperature sensor fault
400Water pressure sensor communication fault
443Low water cut-off (LWCO) activated
520Gas solenoid valve circuit – flame after valve close
540High exhaust (flue gas) temperature
610Combustion fan motor speed fault
631DHW recirculation pump – insufficient flow
651Water flow control valve fault

All Rinnai Combi Boiler error codes →

Rinnai code 430: homeowner questions

What does Rinnai code 430 mean?

High or low system water pressure. System pressure is outside the normal 13–87 psi band. Between 7 and 13 psi the boiler runs derated (warning); at 7 psi or less, or 87 psi and above, it shuts down.

Is it safe to keep using my combi boiler with code 430?

It depends on the cause. The combi boiler has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.

Can I reset Rinnai code 430 myself?

You can try one reset (power off for 30 seconds, then on). If Rinnai code 430 comes back, the cause is still there and a licensed technician should check it.

Who can fix Rinnai code 430 near me?

Aurora Star Tech Inc. repairs Rinnai combi boilers in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: Tankless Water Heater No Hot Water: What to Check · Boiler Not Heating: What to Check

Source: Rinnai Troubleshooting I-Series Plus Boiler Diagnostic Codes (800000375), p.28. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

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