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Item
7. Winding/Coil
heating control
Operation flow and applicable data, etc.
When the outdoor temperature is low, the windings/coils
are heated to ensure compressor reliability.
Description
Winding/Coil heating is performed
when the following conditions are
met.
Condition 1 :
When the discharge sensor tempera-
ture (Td) is less than 30°C.
Condition 2 :
When 2 hours or more have elapsed
after cooling, dry or heating opera-
tion stops.
Condition 3 :
When the outdoor sensor tempera-
ture (To) is as shown in the left
figure.
8. Defrost control
(Only in heating
operation)
(This function removes frost adhered to the outdoor heat
exchanger.)
The temperature sensor of the outdoor heat exchanger
(Te sensor) judges the frosting status of the outdoor heat
exchanger and the defrost operation is performed with
4-way valve reverse defrost system.
The necessity of defrost operation is
detected by the outdoor heat
exchanger temperature. The condi-
tions to detect the necessity of
defrost operation differ in A, B, or C
zone each. (Table 1)
<Defrost operation>
• Defrost operation in A to C zones
1) Stop operation of the compressor
for 20 seconds.
2) Invert (ON) 4-way valve 10
seconds after stop of the com-
pressor.
3) The outdoor fan stops at the same
time when the compressor stops.
4) When temperature of the indoor
heat exchanger becomes 38°C or
lower, stop the indoor fan.
<Finish of defrost operation>
• Returning conditions from defrost
operation to heating operation
1) Temperature of outdoor heat
exchanger rises to +8°C or higher.
2) Temperature of outdoor heat
exchanger is kept at +5°C or
higher for 80 seconds.
3) Defrost operation continues for
15 minutes.
<Returning from defrost operation>
1) Stop operation of the compressor
for approx. 50 seconds.
2) Invert (OFF) 4-way valve approx.
40 seconds after stop of the
compressor.
3) The outdoor fan starts rotating at
the same time when the compres-
sor starts.
Table 1
A zone
B zone
C zone
When Te0 - TE ≥ 2.5 continued for 2 minutes in
A zone, defrost operation starts.
When the operation continued for 2 minutes in
B zone, defrost operation starts.
When Te0 - TE ≥ 3 continued for 2 minutes in C
zone, defrost operation starts.
*
The minimum value of Te sensor 10 to 15 minutes after
start of operation is stored in memory as Te0.
–1˚C
–3˚C
OFF
20W
–4˚C
0’ 10’ 15’ 29’ 34’
–6˚C
–25˚C
Operation time
(Minute)
Start of heating operation
Outdoor temperature To Winding/Coil
heating amount
*
Outdoor heat exchanger temperature
C zone
A zone
B zone