electric heater (B7), and also the water return temperature is lower than the difference between "the set
temp. in heating" and "the temp. difference of electric heater startup", if the above conditions are met,
electric heater will startup. When the real ambient temperature is higher than "the ambient temperature of
permitted electric heater startup", or the compressor stops, the electric heater will shut off.
16.6 Defrosting control
In heating mode, if the system meets the defrosting condition, it will permit one compressor to defrost. If the
ambient is lower than "ambient temperature of two kinds of defrosting time interval" (A6), the interval of one
compressor for two defrosting is "defrosting interval time 1" (A2); if the ambient is higher than A6, the
interval of one compressor for two defrosting is "defrosting interval time 2" (A3).
If for one compressor unit of a certain module, the temperature difference between the real ambient temp
and condenser temp is higher than "temp difference between permitted defrosting temp and the condenser
fins "(factory parameter A5), and also if it has met the interval for the second defrosting, this unit will enter
the defrosting mode, meanwhile, the corresponding bypass valve will open.
When the total defrosting time has arrived the set value of "permitted defrosting time" (A1), or when the
temperature of the condenser fins has increased to the set value of "fin temperature after finishing
defrosting", this unit will quit the defrosting mode.
16.7 Protection signal
Every module is with 9 ways of ON/OFF protection signal to protect the compressor, fan motor and the flow
switch. For the failures such as water flow (C4), low pressure in refrigerant circuit (C5), fan motor (C6),
compressor overload (C7), the unit can set different delay to adapt the device.
" discharging abnormal protection temp." (C1) is used to avoid compressor discharging temp. over heat.
When discharging temp. exceeds the set value, the relative compressor and fan motor will stop; when
discharging temp. is below "discharging abnormal resume temp." (C2), the relative module will quit the
When temp. sensor is abnormal (open circuit or short circuit), the relative module will stop. When the water
return temp. sensor of the master module is abnormal, the whole system will stop.
"malfunction auto resume time" (C3) is used to set the reasonable time to resume the unit after the failure is
eliminated, to avoid the frequent start/stop.
When the communication between a module and the wired controller is abnormal, the module will stop. The
communication failure code and the relative module code will display on the wired controller.
16.8 Anti-freezed function
In switch off state, when water outlet temperature is lower or equal 3℃, and over 2℃, the water pump will