Hummel Premium - Troubleshooting and Maintenance

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25. Troubleshooting and maintenance
Error code on
display
Problem Remedy
Battery symbol
( )
Battery power
too low
Replace batteries
F1
Valve actuator
sluggish
Check installation,
inspect heating
valve
F2
Adjusting range
too large
Check
actuator
fastening
F3
Adjusting range
too small
Check heating
valve
F4
1 wall thermo-
stat already
taught in
Teach out devices
F5
4 wireless com-
ponents already
taught in
At 12:00 every Saturday, the actuator performs a
weekly descaling function to prevent valve calcifica-
tion. “CAL” will appear on the display.