Carrier Error Code PH91: Evaporator coil too cold (Mini-Split)
Carrier error code PH91 on a mini-split means: Evaporator coil too cold. It is also called Carrier diagnostic code PH91.
Homeowner? What Carrier code PH91 means for you
Check, then call Your ductless mini-split is reporting: Evaporator coil too cold. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.
Safe things you can check yourself
- Check the remote: fresh batteries and the right mode (Cool, Heat or Auto).
- Check the breaker and the outdoor disconnect; both should be ON.
- Open the front cover of the indoor unit and rinse the washable filters if they are dusty; let them dry before putting them back.
- Keep the outdoor unit clear of snow, ice and leaves.
- Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.
Call (647) 657-2977Book a service call
Licensed technicians serving Vaughan, Toronto and the GTA.
What does Carrier error code PH91 mean?
Indoor coil temperature too low (cooling). The manuals give no flow chart; it is a protection stop.
Applies to: DLCM(R/H)B multi-zone outdoor units with DLFSHBH high wall indoor units (Midea, Carrier, Viessmann)
Carrier models that use code PH91
DLCMHBH24CAKDLCMHBH30DAKDLCMHBH36DAKDLCMHBH48EAKDLCMRBH18BAKDLCMRBH36DAKDLCMRBH48EAKDLFSHBH09XAKDLFSHBH12XAJDLFSHBH12XAKDLFSHBH18XAKDLFSHBH24XAK
Other Carrier Mini-Split codes
All Carrier Mini-Split error codes →
Carrier code PH91: homeowner questions
What does Carrier code PH91 mean?
Evaporator coil too cold. Indoor coil temperature too low (cooling). The manuals give no flow chart; it is a protection stop.
Is it safe to keep using my ductless mini-split with code PH91?
It depends on the cause. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.
Can I reset Carrier code PH91 myself?
You can try one reset (power off for 30 seconds, then on). If Carrier code PH91 comes back, the cause is still there and a licensed technician should check it.
Who can fix Carrier code PH91 near me?
Aurora Star Tech Inc. repairs Carrier ductless mini-splits in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.
Homeowner help: AC Running But Not Cooling: What to Check · Heat Pump Not Heating or Blowing Cold Air
Troubleshooting guides
- Indoor unit leaking water All brands · Mini-Split
- Poor capacity / high head All brands · Mini-Split
- Water leaking All brands · Mini-Split
- Discharge the inverter capacitors before service Carrier · Mini-Split
- Display shows a strange code or does not answer the remote - DLFSHB indoor Carrier · Mini-Split
- Multi-zone: one room heats, another will not cool - DLC multi-zone Carrier · Mini-Split
- Read live data with the outdoor check button (SW1) Carrier · Mini-Split
- Run the automatic wiring / piping correction Carrier · Mini-Split
Source: DLCMRBH/DLCMHBH Multi-Zone Outdoor Service Manual (sold as Midea, Carrier and Viessmann Vitocal 200-S; Viessmann doc 6225551-03, 12/2024), Table 23 Outdoor Unit Error Display p.26; Carrier MS-DLFSHB-01 High Wall Ductless Service Manual (04/2021), Table 9 p.17. 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.