Gree GWH12MB-K3DNE3G Service Manual page 20

Service Manual
(3) HEAT Mode
① Working conditions and process of heating
If Tamb.≤Tpreset +2°C, the unit enters heating mode, in which case the four-way valve, the compressor and the outdoor fan will
operate simultaneously, and the indoor fan will run at preset speed in the condition of preset cold air prevention.
If T amb.≥Tpreset +5°C, the compressor will stop, the outdoor fan will stop with a time lag of 30s, and the indoor fan will stop after
60-second blow at low speed
If Tpreset +2°C<T amb.< Tpreset +5°C, the unit will maintain its original operating status.
Under this mode, the four-way valve is energized and temperature can be set within a range of 16 - 30°C. The operating symbol, the
heating symbol and preset temperature are revealed on the display.
② Condition and process of defrost
When duration of successive heating operation is more than 45 minutes, or accumulated heating time more than 90 minutes, and
one of the following conditions is reached, the unit will enter the defrost mode after 3 minutes.
(1). T outdoor ambient ＞ 5°C, T outdoor tube≤-2°C;
(2) -2°C≤T outdoor ambient ＜ 5°C, T outdoor tube≤-6°C;
(3) -5°C≤T outdoor ambient ＜ -2°C, T outdoor tube≤-8°C;
(4)-10°C≤T outdoor ambient ＜ -5°C, T outdoor tube-T compensatory ≤ (T outdoor ambient-3°C)
(5)T outdoor ambient ＜ -10°C, T outdoor tube-T compensatory ≤ (T outdoor ambient-3°C)
(after energizing, T compensatory=0°C during the first defrosting; if it is not the first defrosting, T compensatory is confirmed by
T outdoor tube of quitting last defrosting: a. when T outdoor tube ＞ 2°C, T compensatory=0°C; b. when T outdoor tube ≤ 2°C, T
compensatory=3°C)
At that time, the indoor fan stops and the compressor stops, and after 30 seconds the outer fan will stop, and then after 30 seconds,
the four-way valve will stop. After 30 seconds, the compressor is initiated for raising the frequency to defrost frequency.
When the compressor has operated under defrost mode for 7.5 minutes, or T outdoor ambient ≥ 10°C, the compressor will be
converted to 46Hz operation. After 30 seconds, the compressor will stop. And after another 30 seconds, the four-way valve will
be opened, and after 60 seconds, the compressor and the outer fan will be started, the indoor fan will run under preset cold air
prevention conditions, and H1 will be displayed at temperature display area on the display panel. Defrost frequency is 85Hz.
③ Protection
◆ Cold air prevention
The unit is started under heating mode (the compressor is ON):
① In the case of T indoor amb. <24°C: if T tube≤40°C and the indoor fan is at stop state, the indoor fan will begin to run at low speed
with a time lag of 2 minutes. Within 2 minutes, if T tube>40°C, the indoor fan also will run at low speed; and after 1-minute operation
at low speed, the indoor fan will be converted to operation at preset speed. Within 1-minute low speed operation or 2-minute non-
operation, if T tube>42°C, the fan will run at present speed.
② In the case of T indoor amb. ≥24°C: if T tube≤42°C, the indoor fan will run at low speed, and after one minute, the indoor fan will
be converted to preset speed. Within one-minute low speed operation, if T tube>42°C, the indoor fan will be converted to preset
speed.
② refers to, under initially heating mode, the indoor ambient temperature before the
① and
Note: T indoor amb. indicated in
command to start the compressor is performed according to the program, or after the unit is withdrawn from defrost, the indoor
ambient temperature before the defrost symbol is cleared.
◆ Total current up and frequency down protection
If the total current Itotal≤6A, frequency rise will be allowed; if Itotal≥7A, frequency rise will not be allowed; if Itotal≥8A, the compressor
will run at reduced frequency; and if Itotal≥9A, the compressor will stop and the outdoor fan will stop with a time lag of 30s.
(4) Fan Mode
Under the mode, the indoor fan will run at preset speed and the compressor, the outdoor fan, the four-way valve and the electric
heater will stop.
Under the mode, temperature can be set within a range of 16 - 30°C .
(5) AUTO Mode
① Working conditions and process of AUTO mode
a. When T ambient ≥26°C, the unit will operate in Cool mode. The set temperature is 25°C.
b. When T ambient ≤22°C, the heat pump unit will operate in Heat mode., set temperature be 20°C; the cooling only unit will operate
in Fan mode, set temperature be 25°C.
c. When 23°C≤T ambient ≤25°C, the unit will operate in the previous state. If it is energized for the first time, it will operate in Fan
mode.
d. Under auto mode, if its cooling mode, operation frequency is same as that under cooling mode; if its heating mode, operation
frequency is same as that under heating mode.
Technical Information
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