12-5
CONTROL SYSTEM
SM HAFRPM 1-A.3 GB
12.4.5 Protections
High pressure protection is applicable to all operating modes.
Deicing control is valid in Heat and Auto Heat Mode only.
Defrosting control is valid in Dry, Cool, Heat and Auto Modes.
No reset after protection modes.
12.4.6 Thermistors
operation
Return air Temp. is detected by RAT (RT1) in normal Mode, or by RCT (R/C sensor)
in I-FEEL Mode.
Indoor Coil Temp. is detected by ICT (RT2).
12.4.6.1
Definition of thermistor faults:
a. Thermistor is disconnected -
The thermistor reading is below -30
o
c.
b. Thermistor is shorted -
The thermistor reading is over 75
o
c.
c. Thermistor Temp reading doesn’t change (irrelevant for RT1) -
(i) This test is performed only once after a unit is switched from
OFF/STBY to operation. At the first occurrence of 10 min
continuous COMP operation, the current ICT & OCT are
compared with those when the COMP was switched from OFF
to ON 10 min before. If the
T is less than 3
o
c, the thermistor is
regarded as defective.
(ii) The ICT and OCT no-change error can be disabled together by
connecting a4.7 kohm resistor (5%) to the OCT connector. These
resistors are equivalent to a thermistor at 43+/-1
o
c and 48+/-1
o
c
respectively.
(iii) Connecting a 4.7k resistor to the ICT connector will disable the
ICT no-change error only.
CONTENTS
