Viessmann Error Code Fb: Vapor injection inlet sensor fault (Mini-Split)
Viessmann error code Fb on a mini-split means: Vapor injection inlet sensor fault. It is also called Viessmann diagnostic code Fb.
Homeowner? What Viessmann code Fb means for you
Check, then call Your ductless mini-split is reporting: Vapor injection inlet sensor fault. 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 Fb mean?
The enhanced vapor injection inlet temperature sensor is open or shorted. Shown on the 48K high heat model.
Applies to: DLCMHBH48EAK (48K high heat) only
Viessmann models that use code Fb
DLCMHBH24CAKDLCMHBH30DAKDLCMHBH36DAKDLCMHBH48EAKDLCMRBH18BAKDLCMRBH36DAKDLCMRBH48EAK
Other Viessmann Mini-Split codes
All Viessmann Mini-Split error codes →
Viessmann code Fb: homeowner questions
What does Viessmann code Fb mean?
Vapor injection inlet sensor fault. The enhanced vapor injection inlet temperature sensor is open or shorted. Shown on the 48K high heat model.
Is it safe to keep using my ductless mini-split with code Fb?
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 Fb myself?
You can try one reset (power off for 30 seconds, then on). If Viessmann code Fb comes back, the cause is still there and a licensed technician should check it.
Who can fix Viessmann code Fb 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 24 Outdoor Unit Error Display (48 High Heat only) p.27; diagnosis p.51. 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.