
5 Control system
Standard operation sequence
SMGB0091 rev.2 - 11/2015
88
Condition for Starting Defrost
1
Standard defrost
a.
Temperature condition
Model
RASC-(4-10)HNPE
Temperature
condition under
defrosting operation
Outdoor evaporating
temperature (ºC) (Pipe)
Defrosting
operation start area
Outdoor
temperature
(ºC)
b.
Condition for operating time of defrost operation start
The defrosting operation is started when the temperature condition is met “(a) Temperature Condition” after the
heating operation is performed for 40 to 120 minutes. The heating operation time is determined by estimating the
amount of frosting on the heat exchanger.
2
Forced Defrost
Condition for Starting
The forced defrosting operation is started when all the following conditions are met.
a.
120 minutes are passed after the reversing valve is “ON”.
b.
The outdoor temperature is lower than 10ºC.
c.
The accumulated heating operation time is more than 60 minutes.
(The accumulated time is reset when the operation is stopped or the defrosting operation is performed.)
d.
The compressor is operated continuously for more than 1 and half minutes.
e.
The outdoor evaporating temperature is lower than 5ºC right before starting the operation.
f.
The pressure switch for control is “OFF”.
Condition for completing defrost operation
The defrosting operation is stopped when any of following conditions are met.
1
The outdoor evaporating temperature becomes more than 25ºC for 2 minutes from starting the defrosting operation.
2
The outdoor evaporating temperature becomes more than 15ºC (the outdoor temperature < 10ºC) after passing 2
minutes from starting the defrosting operation.
3
The outdoor evaporating temperature becomes more than 5ºC (the outdoor temperature > 10ºC) after passing 2
minutes from starting the defrosting operation.
4
The pressure switch for control is “ON”.
5
More than 9 minutes are passed after starting the defrosting operation.
?
N O T E
• The defrosting operation is not started immediately even if the above conditions are met. (The defrosting condition may be met
temporally depending on the refrigerant cycle variability.)
• The defrosting operation is started when the conditions are met continuously for period of time.