20
3. Defrosting
Defrosting of outdoor heat exchanger is controlled by DEICER P.C. board, with detection by the defrost thermistor RT61.
(1) Starting conditions of defrost
When all conditions of a) ~ c) are satisfied, the defrosting operation starts.
a) The compressor cumulative operation time exceeds 40 minutes without the defrosting operation working.
b) The defrost thermistor RT61 reads - 3°C or less.
c) After releasing the high pressure protection 4 minutes and 15 seconds have elapsed.
(2) Releasing conditions of defrost
When the condition d) or e) is satisfied, the defrosting operation stops.
d) The defrost thermistor RT61 reads 3°C or more.
e) The defrosting time exceeds 10 minutes.
(3) Defrosting time chart
NOTE1 : When the indoor coil thermistor reads above 18°C, indoor fan operates at VLo for 30 seconds.
When the indoor coil thermistor reads 18°C or less, the indoor fan stops.
NOTE2 : Refer to the Service Manual OB227 REVISED EDITION-B when MCFH-13NV-
is connected with MXZ-32RV-
as multi system units.
E1
E3
3
:
or more
-3
:
or less
Outdoor 52C contactor
(Compressor)
X62
(Reversing valve.coil)
SR61
Outdoor fan
Defrost
counter
Indoor fan
Indoor vane
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
Position 1
Set
Position
Max 10 min.
30 sec.
15 sec.
30 sec.
5 sec.
NOTE1
Defrost thermistor RT61
VLo
