Product information | Functions Suitable for HVAC Us

Functions Suitable for HVAC Us

Linearization function

This function estimates the target pressure using the load flow rate, which allows the estimated terminal pressure to be controlled.
For an air-conditioning heat source system, the needed quantity of the cooling or heating water fluctuates generally in seasons or days and nights. Therefore, operations continuing in a water conveyance pressure constant control may lead to high operating unnecessary pressures on terminals at low operating state. Thus, the pump consumes an ineffectual electric power for maintaining the high water conveyance pressure.
Based on the calculated value and water conveyance pressure of estimated terminal pressure using the detected load flow rate, PID control is performed.
It is possible to reduce the ineffectual pump power consumption and to achieve a great energy-saving effect together with maintaining comfortable current air conditioning.

Wet-bulb temperature presumption control

This function is optimal for controlling the fan of cooling tower. Since the wet-bulb temperature would become higher than the set temperature when the air temperature is particularly high, water temperature will not reach the set temperature. Therefore, the fan keeps rotating at high speed, failing in energy-saving operation. FRENIC-HVAC automatically estimates the wet-bulb temperature and controls the fan so that the cooling water is interlocked with the air temperature in order not to use unnecessary electric power.

Filter clogging prevention function

This function detects clogging of the fan filter with dust or other materials using the output current and pressure sensor value. When clogging is detected, the fan is rotated in reverse to eject dust, and then resumes rotation in forward to blow air. In addition, the function notifies you of maintenance necessity with the alarm signal.

Customized logic

The customized logic interface function is provided to the inverter body. This enables forming of logic circuit and arithmetic circuit to the digital and analog input and output signals, allowing simple relay sequence to be built while processing the signals freely.

Standard 4PID control

The 4PID control is featured as standard. One PID module is used to control the output frequency of the inverter, and the other three PIDs can be used to control the external system. To utilize all of four PIDs, the optional card (OPC-AIO) needs to be mounted.

Fire mode (forced operation)

This mode ignores (retry) the inverter protection function to continue the operation. In that way, the inverter keeps operating the fan and pump as much as possible in case of emergency such as fire.


Function codes can be read/write, displayed or hidden by setting the two passwords. This prevents erroneous operation or overwriting of function codes. In addition, if a wrong password was input exceeding the specified number of times, the inverter is restricted from operating as the user is regarded as improper.

Pick-up operation function

The pick-up operation function enables smooth starts. If you wish to run a fan currently not run by the inverter and in idle mode, this function searches the speed regardless of the direction of rotation and pick up the motion smoothly. This function allows for smooth operation such as when switching the power supply from the commercial power to inverter in a momentary action.