thyssenkrupp Flow2 fault code F21: Battery under 19 V going up
Likely causes
Low battery
Step-by-step checks
- Drive down to charge
Stairlift faults that stay after these checks are a job for a trained engineer.
Parts that usually fix this INFERRED
Matched by ScootScan from the fault description to parts listed for models that use this control board. Do the checks first – many faults are fixed by charging, a loose plug or a reset – and check the part fits your model before ordering.
Battery listed for the TK Access (thyssenkrupp) Flow2
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Models using this control board
Other thyssenkrupp Flow2 codes
F01 / F02 · F05 / F07 · F12 - F14 · F15 - F17 · F21 · F22 · F23 · F32 · F33 · F37 · F52 / F53 · F55 · F72 · F74 · F75 · F76 · F77 / F78 · Two-tone beep every 13 s · Red LED flashing + fast ping · Red LED steady + fast ping
Source: www.anglian-lifts.co.uk/wp-content/uploads/2022/02/Tab-6-Flow2A.pdf ↗
Summarised from public manuals. Always check the product's own manual before any repair.