Error Messages - B.Pro B.PROTHERM 420 KBUH Translation Of The Original Operating Instructions

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Error messages

Code
HS: (H5) Heating short-
FB: (F6)
FS: (F5)
–
Uo
Uu
B.PROTHERM 420 KBUH/420 KBRUH/620 KBUH/620 KBRUH
Heating
active
Heating
inactive
Error Cause
Short-circuit in the
circuit; power is PTC heating element;
switched off moisture may have en-
tered the PTC heating
element aluminium
housing
Sensor break Defective temperature
sensor, resistance
curve outside toler-
ance
Sensor short- Temperature sensor
circuit input lines generate a
short-circuit; resist-
ance curve outside tol-
erance levels
No display
Overvoltage >260 V
Undervoltage <200 V
– 25 –
Measure
 Check that the
heating element
compound is leak-
tight.
 Fit new heating ele-
ment if necessary.
 Replace NTC sen-
sor.
 Replace NTC sen-
sor
 Check mains sup-
ply lines and unit
fuse on controller
electronics.
 Check mains
voltage
 Check mains
voltage