Haier MRV5-H - 6.4.10 Coil Protection Control; 6.4.11 Anti-Snow Protection; 6.4.12 Heater Control; 6.4.13 Target Pressure Control

67
CH: ON
OFF
Oil temperatureToil (°F) → 140 149
6.4.10 Coil Protection Control
By controlling the frequency of the compressor to control the temperature of the coil, and the coil temperature is
usually controlled at 203°F. Above 203°F, the outdoor fan increases the speed.
6.4.11 Anti-Snow Protection
6.4.12 Heater Control
When the system is running, control the heater according to the following picture.
When the compressor oil temperature Toil is 140-149°F, it starts from ON.
CH: Heater (Crank Case Heater)
6.4.13 Target Pressure Control
①
Cooling low pressure control
Target Pressure Ps When Cooling Remarks
Long piping setting 14.3 lb
Medium piping setting 16.5 lb Factory default setting
Short piping setting 18.3 lb
• During cooling the operating frequency of compressor is fuzzy logic controlled based on target Ps.
• The frequency of compressor goes down and Ps goes up; the frequency of compressor goes up and Ps goes
down.
• During cooling; if the low pressure reaches 152.3 psi, the LEV control of all indoor units will limit suction pressure
to 152.3 psi.
[Note]
The one-way connection piping of the units is generally dened as: when the longest piping is less than 98 ft (30m),
it is short piping; 98-295 ft (30-90m), medium piping; more than 295 ft (90m), long piping. The specic situation is
determined by installation in site.