Panasonic S-36PU1E5A Service Manual page 529

8) Defrosting Control
This control function removes frost that has adhered to the outdoor heat exchanger during the heating operation.
The control is performed to prevent the deterioration of the heating capabilities attributed to the adherence of
frost, and to prevent the crack or crush of pipes attributed to the accretion of ice.
The following control is performed in accordance with the ambient temperature and the outdoor heat exchanger
temperature sensor (C1).
Overall Flow Chart of Defrosting Control
Yes (detected)
(heating mask time) elapsed?
Yes (elapsed)
Defrosting operations commenced
Have the conditions for ending
Yes (satisfied)
Frost adherence detection
• If the following conditions are satisfied during heating operations, it is regarded as "frost adherence is detected".
• Frost adherence detection is performed in accordance with the ambient temperature (TO) and the outdoor heat exchanger
temperature sensor (C1).
• Frost adherence detection conditions
(a) Following satisfied condition is detected for accumulation of 60 minutes.
Outdoor heat exchanger temperature sensor (C1) < L1
(b) Following satisfied condition is detected for consecutive 4 minutes or more, 2 times.
Outdoor heat exchanger temperature sensor (C1) < L2
Outdoor heat exchanger temperature sensor (C1) (°C)
C1
-21.4
-1
-3
-8
-10
-23
-25
(c) Following satisfied condition is detected for accumulation of over 90 minutes.
Outdoor heat exchanger temperature sensor (C1) < -3 °C
Heating Mask Time
This refers to the shortest time that heating operations must be performed without defrosting operations being executed.
The mask time for this model is 35 minutes.
* Defrosting operations will not be commenced until the defrosting mask time has elapsed, even if frost adherence has
been detected.
Normal heating operation
Has frost adherence been
detected?
Has more than 35 minutes
defrosting been satisfied?
Heating operation resumed
Ambient temperature
10
(TO) (°C)
L1
L2
Heating
No
operation
continued
Heating
No
operation
continued
Defrosting
No
operation
continued
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_
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