Haier MRV5-H - 6.4.14 Overheating Protection Control; 6.4.15 Current Protection Control

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①
When the temperature at the top of the compressor rises; the corresponding SV3 is started to conduct the liquid
bypass cooling.
(Refer to Figure) Td high temperature side (≤ 248°F) control / SV3 control
When Td ≥212°F, in cooling, the indoor unit SH modication control, maximum modication value - 5
When Td ≥221°F, control the compressor frequency.
②
Heating high pressure control
Target Pressure Pd When Heating Remarks
Long piping setting 66.1 lb
Medium piping setting 61.7 lb Factory default setting
Short piping setting 57.3 lb
During heating, the operating frequency of compressor is fuzzy logic controlled based on target Pd.
The frequency of compressor goes down and Pd goes down; the frequency of compressor goes up and Pd goes up.
[Note]
For heating capacity; if the discharge pressure is higher then the capacity is higher. However, if the discharge
pressure is higher, the COP of unit will be lower.
6.4.14 Overheating Protection Control
6.4.15 Current Protection Control
①
If the compressor current exceeds the stipulated upper limit value; the operating frequency is reduced for control
before the current changes to exit-value or below.
②
When the current cannot reach the upper limit value or below, even at the lowest rotating speed (20rps), the
compressor will stop operating.
③
If the operating current reaches the exit-value or below, it will return to the target rotating speed.