Defrost Control (Only In Heating Operation) - Toshiba RAS-B16N3KV2-E1 Service Manual

RAS-B10N3KV2-E1, RAS-B13N3KV2-E1
Item
7. Defrost control (This function removes frost adhered to the outdoor
(Only in heating heat exchanger.)
operation)
The temperature sensor of the outdoor heat ex-
changer (Te sensor) judges the frosting status of the
outdoor heat exchanger and the defrost operation is
performed with 4-way valve reverse defrost system.
Start of heating operation
TE [˚C]
0 10
–2
–5
–10
–25
∗ The minimum TE value and To value between 10 and 15 minutes after heating operation has
started are stored in memory as TE0 and To0, respectively.
Table 1
A zone
B zone
C zone
D zone
<Defrost operation>
• Defrost operation in A to C zones
1) Stop operation of the compressor for
2) Invert (OFF) 4-way valve 40 seconds
3) The outdoor fan stops at the same time
4) When temperature of the indoor heat
<Finish of defrost operation>
• Returning conditions from defrost
1) Temperature of outdoor heat exchanger
2) Temperature of outdoor heat exchanger
3) Defrost operation continues for
Operation flow and applicable data, etc.
15
∗
In normal To
TE0-TE³3°C & SH-SH0£2
TE0-TE³2°C & SH-SH0£2
More than 90 minutes accumulated heating operation time condition TE£ -2°C
40 seconds.
after stop of the compressor.
when the compressor stops.
exchanger becomes 38°C or lower,
stop the indoor fan.
operation to heating operation
rises to +8°C or higher for 3 seconds.
is kept at +7°C or higher for 60 seconds.
10 minutes.
The necessity of defrost operation is
detected by the outdoor heat exchanger
temperature. The conditions to detect the
necessity of defrost operation differ in A,
B, or C zone each. (Table 1)
29 35
B zone B zone
C zone C zone
(TE0-TE)-(TO0-TO)³3°C & SH-SH0£2
(TE0-TE)-(TO0-TO)³2°C & SH-SH0£2
TE≤ –25°C & SH-SH0£2
<Returning from defrost operation>
1) Stop operation of the compressor for
approx. 40 seconds.
2) Invert (ON) 4-way valve approx. 30
seconds after stop of the compressor.
3) The outdoor fan starts rotating at the
same time when the compressor starts.
– 37 –
FILE NO. SVM-15006
Description
90
A zone
A zone
D D z
In abnormal To
[min.]
zone one