Rheem mini split error code E4
Compressor discharge temperature too high.
- TypeProtection
- SystemCompressor / inverter
- Can I fix it?Homeowner checks, then maybe a tech
- Applies toFloating Air series (Friedrich-built, Gree platform)
What E4 means on a Rheem
The refrigerant leaving the compressor got hotter than the safe limit. The compressor stops to protect its valves and oil.
On this platform, E4 is a protection: the system stopped or throttled itself to prevent damage; many clear on their own once conditions return to normal.
Common causes
- Low refrigerant charge.
- A blocked outdoor coil or failed outdoor fan.
- A partly closed service valve or restricted line set.
- The discharge temperature sensor reading high (see F5).
- A failing compressor.
How to fix it yourself
Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician.
- 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.
- Confirm the service valves are fully open.
- Let it cool with power off for 30 minutes and retry.
- Anything inside the refrigerant circuit (sensors are fine, but valves, compressors and leaks are not) needs EPA-certified refrigerant handling. That is a technician job.
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
If it recurs with a clean coil and running fan, have a technician check the charge and the discharge sensor.
Which Rheem units show E4
This page applies to Rheem Classic and Classic Plus wall-mount (RIWH / ROWH), Endeavor Line multi-zone and Floating Air series (2023 and later) units on the Floating Air series (Friedrich-built, Gree platform). Rheem's own documentation lists E4 as "Compressor discharge temperature too high", the same definition used across the Gree platform 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 Rheem shows this code
Floating Air series (Friedrich-built, Gree platform): The code shows on the indoor unit's display in place of the temperature. If the display is off, press the Light button on the remote. Some models also count out the code as indicator blinks. E codes are system protections and faults, F codes are mostly sensor faults, H codes are outdoor and compressor protections, U codes are motor and valve faults, and P codes are power-supply faults.
Other Rheem codes
Same part of the system as E4:
E4 on other brands
The same characters do not always mean the same thing. Check the brand on your unit.
- Pioneer E4 Indoor room temperature sensor (T1) open or short circuit / Outdoor temperature sensor fault: coil (T3), ambient (T4), discharge (T5) or a zone coil outlet (T2B)
- Blueridge E4 Compressor discharge temperature too high / Indoor room temperature sensor (T1) open or short circuit
- Gree E4 Compressor discharge temperature too high
- Zone Air E4 Abnormal system operation or lack of refrigerant
- Daikin E4 Low pressure protection
- Mitsubishi Electric E4 Indoor unit signal receiving error (from remote controller)
- Carrier E4 Indoor room temperature sensor (T1) open or short circuit
- Trane E4 Abnormal system operation or lack of refrigerant / Indoor unit signal receiving error (from remote controller)
- Heil E4 Indoor room temperature sensor (T1) open or short circuit / Compressor discharge temperature too high
- ACiQ E4 Indoor room temperature sensor (T1) open or short circuit / Abnormal system operation or lack of refrigerant
Questions people ask
Can I reset a Rheem E4 code myself?
Yes. Turn the system off at the breaker for five minutes, then restart it. If E4 comes back, the fault is real and needs the checks above.
Is it safe to keep running a Rheem showing E4?
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.
Do I need a technician for Rheem E4?
Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician. If it recurs with a clean coil and running fan, have a technician check the charge and the discharge sensor.
Sources
- Rheem RIWH / ROWH Ductless Design and Technical Manual (RIWH18ASJ to RIWH36AXJ)
- Rheem Classic Series ductless installation manual 9318739237 (Fujitsu General document number)
- Friedrich Floating Air Select Service and Parts Manual (2015-2019), diagnostic code table
Updated September 2026. Codes and definitions vary by model year. If your manual disagrees with this page, your manual wins. Send a correction.