Hoshizaki HFE-140B Series, Service Manual

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6
3. ENERGY SAVING FEATURES
[a] FRAME HEATER ENERGIZING CONTROL
The Frame Heater is energized intermittently to keep the Front Frame surfaces at the
optimum temperature for preventing condensation. As the optimum surface temperature
depends on the ambient temperature, the ratio between ON time and OFF time is
determined by the difference between the ambient temperature (measured by the
Temperature Sensor built in the Controller Board) and the cabinet temperature (measured
by the Interior Thermistor). This duty ratio has eight patterns and is updated every two
minutes.
The duty ratios are sorted into seven levels (HRE series) or six levels (HFE series)
depending on the difference between the ambient and cabinet temperatures. The higher
levels at the same ambient and cabinet temperatures mean the higher duty ratios. The
unit is factory adjusted to level 2.
The user is allowed to choose between levels 2 and 3 only, and service persons between
levels 0 - 6 (HRE series) or 1 - 6 (HFE series).
[Reference]
Level 2: No condensation at ambient temperature 35°C, relative humidity 70%
Level 3: No condensation at ambient temperature 35°C, relative humidity 80%
Duty Ratio
(%)
ON time
(sec)
OFF time
(sec)
Ambient temp - cabinet temp
HRE series HFE series
Level 3 Level 2 Level 3 Level 2
2.5 5 05 5 or less 4 or less or less 23 or less
25 30 0 5 - 0 4 - - 6 23 - 30
37.5 45 75 0 - 4 - 24 6 - 23 30 - 37
50 60 60 4 - 24 - 28 23 - 30 37 - 44
62.5 75 45 - 24 28 - 33 30 - 37 44 - 52
75 0 30 24 - 28 33 - 37 37 - 44 52 - 5
87.5 05 5 28 - 33 37 - 4 44 - 52 5 - 66
00 20 0 33 or more 4 or more 52 or more 66 or more
[Relations between duty ratio and ambient and cabinet temperature differences]
HRE series duty ratio
Level 0: Constantly OFF
Level 2: Factory adjustment
Level 6: Constantly ON