Haier H2SM Series Service Manual page 21

heating operation. During the operation, outdoor compressor A and the 4-way valve operate 1
second before the fan starts, 20 seconds later, outdoor compressor B starts heating operation.
6.2. Once an outdoor compressor starts, the other compressor will not start in 20 seconds from the
start.
6.3. When changed from cooling to heating, the compressor stands by for 3 minutes. When both
compressors are in the strand-by status, the outdoor fan stops. Otherwise, it operates. The status
of the fan depends on the number of the compressors that operate.
6.4. When the outdoor ambient temperature T1¡Ü10¡æ, the outdoor fan runs at the high speed.
There is a return difference for the change between high and medium speed;
When the outdoor ambient temperature T1¡Ý20¡æ, the outdoor fan runs at the low speed. There
is a return difference for the change between low and medium speed.
6.5. Once a fan operates in a mode, it must operate for more than 45 seconds.
7. Cooling and heating operations take place at the same time:
7.1. When one of the indoor units gives out a cooling signal and another unit gives out a heating
signal at the same time, the outdoor fan operates at the low speed.
7.2. When the indoor unit gives the value of coil temperature, the outdoor fan runs at the low speed if
the heating outdoor unit judges high load.
7.3. When outdoor ambient temperature T1¡Ý28¡æ, there is no heating operation.
7.4. When outdoor ambient temperature T1¡Ü7¡æ, there is no cooling operation.
7.5. Once a compressor starts, the other compressor will not start in 20 seconds from the start.
8. Single-unit heating operation with heat load:
8.1. In the single-unit heating operation, the indoor unit gives out the value of the coil temperature,
and the outdoor unit judges whether to start in the high load protection operation based on the
value of the coil temperature it has received. If the conditions for high load protection are met, the
outdoor fan stops immediately. It will restart 45 seconds later if the signal for the outdoor heat load
disappears. Otherwise, the outdoor fan will continue to stop until the signal for the outdoor heat
load disappears. The signal for heat load is as follows:
High temperature protection: When the indoor coil temperature higher than T_OFS (56¡æ), the
outdoor fan stops; when the coil temperature falls to T_OFR (52¡æ), the outdoor fan restarts. The
outdoor fan stops for more than 45 seconds.
Air Conditioner
17
Edition:2006/1/10