Troubleshooting
4.3
Faults of the cooling system
Temperature of inner chamber does not de-
crease to set temperature below ambient
temperature
Controller regularly displays the operating
parameters
Optional class 3.3 undertemperature set too
high?
Yes
Operating error (see operating manual)
No
Does the outer door fit closely?
No
Adjust the outer door (chap. 6.1, page 41)
Yes
Outer door gasket and / or glass door gasket
defective?
Yes
Replace outer door gasket and / or glass door
gasket (chap. 6.2.6, page 50 and chap. 7.5,
page 62)
No
Compressor (
-6M1
) defective?
Yes
Have replaced the compressor
No
24 V power supply unit (-2
T1
) defective? Sec-
ondary voltage 24 V at contactor (
–X30
) pins 1
and 2
Yes
Replace 24 V power supply unit
(chap. 8.12, page 89)
No
Solid state relay (
-7K1
) defective?
Yes
Replace Solid state relay
(chap. 8.6, page 82)
No
Coils of the solenoid valve (
-7Y1
) defective?
Yes
Replace coils of the solenoid valve
No
Valve body of the solenoid valve
(-7Y1)
defec-
tive? Test the function with a permanent magnet
(“click” sound)
Yes
Have replaced the valve body of the solenoid
valve
No
Service Manual KBF (E5.2) 04-2015
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