４９
empty. Turn the knob of temperature controller to middle or near to strong
position and close the door or cover. Make the measurement at least 30 min.
after freezer operation.
During test, if the freezer reaches the temperature the knob stipulated, and
the freezer stops, the measurement must be interrupted and resume 3min.
after the freezer starts again.
The test environment is semi-sound-eliminating-room. Other test field must
comply with the stipulations in GB4214.
The test of noise is carried out as shown in figure 8. Put sound transfer
units to measurement point 1,2,3,4, measure the sound level by sound level
meter (A weighted). Take the greater readings and calculate the average
value. The arithmetic average value of these four points is taken as the
average sound pressure level noise.
According to the testing result, sound power level of the freezer being
measured can be calculated out.
L
W
=(L
PA
-2)+10LgS
Where: L
W
--A sound power level, dB (datum value is 1PW);
L
PA
--average sound pressure level of measuring surface,
dB(datum value is 20
μ
Pa);
S
—
measuring surface enveloped area, m
2
MAINTENANCE SERVICE AND TROUBLE SHOOTING
Maintenance Service and Trouble Shooting
Assume l1, l2, l3 is the length, width, height of freezer respectively, unit is
m.
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