DIY HVAC Tools

EG4 mini split error code 87

IPM fault signal (level). Also shown as 87.

  • TypeProtection
  • SystemCompressor / inverter
  • Can I fix it?Technician job

What 87 means on a EG4

The inverter power module is holding its fault line active: a persistent short, over-temperature, or a failed module.

On this platform, 87 is a protection: the system stopped or throttled itself to prevent damage; many clear on their own once conditions return to normal.

Common causes

  • A failed IPM.
  • A shorted compressor winding.
  • The module overheating.

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. Look at the outdoor unit: clear leaves, cottonwood fluff, snow or ice from the coil and make sure the fan can spin freely and nothing is stacked against the cabinet.

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 diagnosis; usually a board replacement.

Which EG4 units show 87

This page applies to EG4 12K hybrid solar mini split (AC/DC, R32) and 12K / 24K hybrid mini split AC/DC R32 (DWA4 / DWB3 / DGA) units. EG4's own documentation lists 87 as "IPM fault signal (level)", the same definition used across the EG4 hybrid solar mini split 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 EG4 shows this code

The indoor unit's LED display shows a two-digit number in place of the temperature. EG4 units also run on DC from solar panels, so several codes concern the DC input and the power stage rather than the refrigerant side. 01 to 06 are indoor and communication faults, 31 to 37 are temperature sensors, 51 to 58 are motors, 72 to 79 are voltage and current protections, and 81 to 96 are inverter and compressor drive faults.

Other EG4 codes

Same part of the system as 87:

55Compressor feedback error75Compressor high temperature protection79Demagnetization protection (compressor motor)86IPM fault signal (edge)91IPM over-temperature92Compressor lack of phase93Compressor lost speed94IPM over-voltage
01Indoor unit data error (EEPROM)03Communication error between indoor and outdoor units04Indoor unit buttons stuck05Outdoor unit data error (EEPROM)06Indoor fan motor fault31Indoor air (room) temperature sensor fault (open or short circuit)32Indoor evaporator temperature sensor fault (open or short circuit)35Outdoor air temperature sensor fault (open or short circuit)

All EG4 error codes

Questions people ask

Can I reset a EG4 87 code myself?

Yes. Turn the system off at the breaker for five minutes, then restart it. If 87 comes back, the fault is real and needs the checks above.

Is it safe to keep running a EG4 showing 87?

Not repeatedly. A protection code means the unit stopped itself to prevent damage, and resetting it over and over can turn a cheap repair into a compressor failure. Reset once, check the basics, and stop if it returns.

What will a technician check for 87?

Technician diagnosis; usually a board replacement. Ask for the measurements, not just a parts quote.

Sources

  • EG4 12K Hybrid Solar Powered Mini-Split R32 User Manual (2025), section 14.3 Indoor Unit LED Error Codes
  • EG4 12K / 24K Hybrid Mini-Split AC/DC R32 User Manual (10/2025)

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