DIY HVAC Tools

Goodman mini split error code H3

High-pressure switch fault.

  • TypeFault
  • SystemControl board
  • Can I fix it?Technician job

What H3 means on a Goodman

The high-pressure switch circuit is open or reading wrong even when pressure is normal.

On this platform, H3 is a fault: something has failed or is disconnected and needs diagnosis.

Common causes

  • A failed switch.
  • A loose switch connector.
  • A failed board input.

How to fix it yourself

Do the reset and the visual checks, but the underlying repair needs a technician with a meter and the service manual.

  1. Reset the system: switch the breaker (or the outdoor disconnect) off, wait a full five minutes so the boards fully discharge, then switch it back on and restart from the remote.
  2. With power off, reseat the pressure switch connector on the outdoor board.

Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.

When to call a technician

Technician job.

Which Goodman units show H3

This page applies to Goodman e-Series wall-mount (FTXNG indoor / RXNG outdoor) units. Goodman's own documentation lists H3 as "High-pressure switch fault", the same definition used across the Daikin it is built on. If your unit shows a code with a different shape (for example a four-character code, or a plain number), it is from a different table; use the lookup with your exact code.

Where Goodman shows this code

Most Daikin wall units do not show the code on the unit; the operation lamp blinks. To read the code, point the remote at the unit, hold CANCEL (or Timer Cancel) for about 5 seconds until 00 shows, then press CANCEL repeatedly. Each press shows a code; when the unit gives a long continuous beep instead of two short beeps, the code on the remote is the stored fault. Units with a wired controller show the code directly. A and C codes are indoor-unit faults, E, F, H, J, L and P codes are outdoor-unit faults and protections, and U codes are system-level problems such as communication, power supply and refrigerant shortage.

Other Goodman codes

Same part of the system as H3:

A1Indoor unit control board (PCB) failureE1Outdoor unit control board (PCB) failureH0Compressor sensor system (voltage or current) faultH8Compressor input current (CT) system fault
00No fault stored (normal)A3Drain water level abnormal (float switch)A5Freeze-up protection (cooling) or high-pressure control (heating)A6Indoor fan motor fault (locked or abnormal)A9Indoor electronic expansion valve (EEV) faultC4Indoor heat exchanger (liquid pipe) temperature sensor fault (open or short circuit)C5Indoor heat exchanger (gas pipe) temperature sensor fault (open or short circuit)C7Front panel (open/close) drive fault

All Goodman error codes

H3 on other brands

The same characters do not always mean the same thing. Check the brand on your unit.

Questions people ask

Can I reset a Goodman H3 code myself?

Yes. Turn the system off at the breaker for five minutes, then restart it. If H3 comes back, the fault is real and needs the checks above.

Is it safe to keep running a Goodman showing H3?

The unit will usually refuse to run, or run with reduced output, until the fault is cleared. Repeated resets do not fix anything and can mask a problem that is getting worse.

What will a technician check for H3?

Technician job. Ask for the measurements, not just a parts quote.

Sources

  • Goodman e-Series product documentation (FTXNG / RXNG models)
  • Daikin residential (RA) service manuals (error code tables)

Updated September 2026. Codes and definitions vary by model year. If your manual disagrees with this page, your manual wins. Send a correction.