Buderus Logamax plus GB142-24 Servicing Instructions page 64

7 Diagnosis
Locking boiler fault code 4Y
2 2 3
4 Y
C Y
2 4 1
Press the "Reset" button.
New fault message
4Y or
Check the wire to the supply or return sensor
for the proper contact (page 92).
Is the wire okay?
Check the supply and return sensor
(page 89).
Are the supply
and return sensors okay?
44
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64 Logamax plus GB142-24/30/45/60 - We reserve the right to make any changes due to technical modifications!
The supply sensor contact is interrupted.
The return sensor contact is interrupted.
No
C Y ?
Yes
No
Yes
No
Yes
Locking boiler-fault code.
Locking boiler-fault code.
Replace the cable loom or the affected part
thereof.
Replace the supply and return sensor
(page 91).
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