Alarms & safety functions – Sanyo MDF-U537 User Manual
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ALARMS & SAFETY FUNCTIONS
This unit has the alarms and safety functions shown in Table 5, and also self diagnostic functions.
Table 5 Alarms and safety functions
Alarm & Safety
Situation
Indication
Buzzer
Safety operation
High temperature 
alarm 
If the chamber temperature is higher
than the temperature at which the 
high temperature alarm is activated.
ALARM lamp is flashed. 
Temperature indicator is 
flashed. 
Intermittent tone with 
15 minutes delay. 
Remote alarm with 15 
minutes delay. 
Low temperature 
alarm 
If the chamber temperature is lower 
than the temperature at which the 
low temperature alarm is activated. 
ALARM lamp is flashed. 
Temperature indicator is 
flashed. 
Intermittent tone with 
15 minutes delay. 
Remote alarm with 15 
minutes delay. 
Power failure alarm
In the case of power failure. 
When power switch is turned OFF. 
When the power to the unit is 
disconnected. 
ALARM lamp is flashed.
Intermittent tone
Remote alarm.
Auto-return
When there is no key pressing in 
each setting mode for 90 seconds. 
Chamber temperature is 
displayed. 
-----
Finishing of each 
setting mode. 
Key lock
When the key lock is “ON”.
-----
-----
Change of setting is 
disable. 
If the thermal sensor is 
disconnected. 
ALARM lamp is flashed. 
E01 and chamber temp. are 
displayed alternately. 
Intermittent tone
Remote alarm. 
Continuous running. 
Thermal sensor 
Abnormality 
(for MDF-U537D, 
upper chamber 
only) 
If the thermal sensor is 
short-circuited. 
ALARM lamp is flashed. 
E02 and chamber temp. are 
displayed alternately. 
Intermittent tone
Remote alarm. 
Continuous running. 
If the thermal sensor is 
disconnected. 
ALARM lamp is flashed. 
E03 and chamber temp. are 
displayed alternately. 
Intermittent tone
Remote alarm. 
Continuous running. 
Thermal sensor 
abnormality 
(MDF-U537D, 
lower chamber 
only) 
If the thermal sensor is 
short-circuited. 
ALARM lamp is flashed. 
E04 and chamber temp. are 
displayed alternately. 
Intermittent tone
Remote alarm. 
Continuous running. 
If the protective sensor for 
compressor is disconnected. 
ALARM lamp is flashed. 
E05 and chamber temp. are 
displayed alternately. 
Thermal sensor 
abnormality 
(MDF-U537, U537D 
only) 
If the protective sensor for 
compressor is short-circuited. 
ALARM lamp is flashed. 
E06 and chamber temp. are 
displayed alternately. 
Intermittent tone
Remote alarm. 
Normal operation. 
If the thermal sensor for lower 
chamber is disconnected. 
ALARM lamp is flashed. 
E07 and chamber temp. are 
displayed alternately. 
Thermal sensor 
abnormality 
(MDF-U537 only) 
If the thermal sensor for lower 
chamber is short-circuited. 
ALARM lamp is flashed. 
E08 and chamber temp. are 
displayed alternately. 
Intermittent tone
Remote alarm. 
Normal operation. 
Battery switch
check
When battery switch is OFF at the 
time of alarm test. 
ALARM lamp is flashed. 
E09 is flashed. 
Intermittent tone
Remote alarm.
Compressor temp. 
Abnormality (MDF- 
U537, U537D only) 
In the case of failure of compressor 
cooling fan motor. 
In the case of abnormal high 
temperature due to the dust on the 
condenser. 
In the case of abnormal high 
ambient temperature. 
E10 and chamber temp. are 
displayed alternately. 
Intermittent tone
Remote alarm. 
Compressor stops 
running when the temp
reaches about 100
o
C.
Electromagnetic valve 
1, 2 and compressor 
stop. 
(MDF-U537D only) 
Note:
1. The above power failure alarm is available when the battery switch is ON and the battery is charged.
If the battery switch is OFF or the battery is discharged, only the remote alarm is activated.
2. The power failure alarm can be kept about 12 hours with the battery charged completely. 2-day
operation of the freezer is needed to charge the battery full.
3. The chamber temperature is displayed for 5 seconds if the BUZZER key is depressed during the power
failure alarm. At the same time, the alarm stops.
4. The remote alarm is silenced by pressing BUZZER key as the remote alarm is operated in conjunction
with the buzzer, except for the power failure alarm.
5. After power failure, the operation is resumed with the condition before power failure since the
temperature setting and alarm temperature setting are memorized in a nonvolatile memory.
