Viessmann Error Code PH90: Evaporator coil too hot (Mini-Split)
Viessmann error code PH90 on a mini-split means: Evaporator coil too hot. It is also called Viessmann diagnostic code PH90.
Homeowner? What Viessmann code PH90 means for you
Check, then call Your ductless mini-split is reporting: Evaporator coil too hot. 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 Viessmann error code PH90 mean?
Indoor coil temperature too high (heating). 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)
Viessmann models that use code PH90
DLCMHBH24CAKDLCMHBH30DAKDLCMHBH36DAKDLCMHBH48EAKDLCMRBH18BAKDLCMRBH36DAKDLCMRBH48EAKDLFSHBH09XAKDLFSHBH12XAJDLFSHBH12XAKDLFSHBH18XAKDLFSHBH24XAK
Other Viessmann Mini-Split codes
All Viessmann Mini-Split error codes →
Viessmann code PH90: homeowner questions
What does Viessmann code PH90 mean?
Evaporator coil too hot. Indoor coil temperature too high (heating). The manuals give no flow chart; it is a protection stop.
Is it safe to keep using my ductless mini-split with code PH90?
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 Viessmann code PH90 myself?
You can try one reset (power off for 30 seconds, then on). If Viessmann code PH90 comes back, the cause is still there and a licensed technician should check it.
Who can fix Viessmann code PH90 near me?
Aurora Star Tech Inc. repairs Viessmann 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 Viessmann · Mini-Split
- Display shows a strange code or does not answer the remote - DLFSHB indoor Viessmann · Mini-Split
- Multi-zone: one room heats, another will not cool - DLC multi-zone Viessmann · Mini-Split
- Read live data with the outdoor check button (SW1) Viessmann · Mini-Split
- Run the automatic wiring / piping correction Viessmann · 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.