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3. Defrosting (Refer to page 70 for MXZ30TN MXZ30TN2)
Defrosting of outdoor heat exchanger is controlled by deicer P.C. board, which detection by the defrost thermistor RT61.
(1) Starting conditions of defrost
When all conditions of a) ~ c) are satisfied, the defrosting operation starts.
a) Under the heat operation, the compressor cumulative operation time exceeds 40 minutes (MSH09TW, MSH12/15/
17TN) /15 minutes (MSH09TW -
, MSH12/15/17TN-
, MSH12/15TN-
) without the defrosting operation
working.
b) The defrost thermistor RT61 reads 27˚F or less (MSH09TW, MSH12/15/17TN) / 32°F or less (MSH09TW -
,
MSH12/15/17TN-
, MSH12/15TN-
).
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 38˚F or more (MSH09TW, MSH12/15/17TN) / 50°F or more (MSH09TW -
,
MSH12/15/17TN-
, MSH12/15TN-
).
e) The defrosting time exceeds 10 minutes.
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NOTE:
●
When the indoor coil thermistor RT12 reads above 64˚F, indoor fan operates at Very Low for 30 seconds since
RT61 has read the working temperature of defrosting.
●
When the indoor coil thermistor RT12 reads 64˚F or less, the indoor fan stops.
(3) Defrosting time chart
Defrost thermistor RT61
Outdoor 52C
contactor(Compressor)
X62
(R.V. coil)
SR61
Outdoor fan
Defrost
counter
Indoor fan
Indoor vane
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
Horizontal
Set position
Max 10 min.
30 sec.
15 sec.
30 sec.
5~15 sec.
NOTE
50°F or more
(MSH09TW -
, MSH12/15/17TN-
,
MSH12/15TN-
)
38˚F or more
(MSH09TW, MSH12/15/17TN)
32°F or less
(MSH09TW -
, MSH12/15/17TN-
,
MSH12/15TN-
)
27°F or less
(MSH09TW, MSH12/15/17TN)
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OB275--2.qxp 03.12.2 16:50 Page 59
Summary of Contents for MSH09TW
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