Bosch B22CS50SNW-01 General Repair - Instruction page 13

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Flowing noises on the evaporator
Loud flowing noises are generated by residual air in the refrigeration
circuit. The circuit must not be rinsed while there are flowing noises.
Type of noises:
Rustling, splashing, gurgling, bubbling.
Remedial action:
Carefully evacuate refrigeration circuit on both sides for at least
15 minutes. Then fill the appliance according to the instructions.
If the appliance is not filled according to the instructions, air may get
into the refrigeration circuit.
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Injection noises on the evaporator
The refrigerant is injected at high speed into the evaporator at the end
of the throttle tube (injection point). If the end of the throttle tube is
bent, increased injection noises will occur.
Type of noises:
Fizzing, hissing, whistling, trumpeting, scratching.
Remedial action:
There is no remedial action for refrigerator compartment aluminium
evaporators. The throttel tube is not accessible at the injection point.
If the freezer compartment features a wire tube evaporator, check that
the throttle tube runs straight in the injection area (in front of the
soldered joint). If required, carefully straighten the tube (risk of
fracture)! Jacket the injection point with absorption material, material
no. 00153737.
173_58300000002379_ara_en_j.doc – 29.04.14
2.9.3 History of noise generation
The type of noises has changed in modern refrigerators/freezers.
Modern appliances are usually quieter than old refrigerators/freezers.
However, the noises have changed on account of energy-saving
compressors, environmentally friendly refrigerants and internally
foamed evaporators, ranging from low to high-frequency sounds.
High sounds are usually felt to be more offending than low sounds
(comparison: mosquito – bee)
2.9.4 Noise diagnosis
If a complaint is made, assess the volume of the noise when the
appliance door is closed.
In the case of a customer complaint about multi-zone appliances,
check which zone is generating the noise. Only then decide how to
proceed further.
The two following flow diagrams will help you decide how to proceed
and how to test for noises.
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