The Yierp four-pipe five-constant host integrates two independent water-side heat exchange circuits internally, with its core hardware divided into major sections: refrigerant circuit components, dual water-side heat exchange components, built-in hydraulic components, intelligent valve group units, and main control and communication acquisition units achieving the capability of simultaneous dual water temperature output.
Core components of the refrigerant circuit
Full-frequency inverter compressor, four-way reversing valve group, dual electronic expansion valves, outdoor fin heat exchanger, gas-liquid separator, receiver. The compressor acts as the energy source, performing work by compressing the refrigerant; the dual electronic expansion valves can independently regulate the refrigerant flow to the two plate heat, which is the key throttling component for generating two different water temperatures; the four-way valve group is responsible for switching the refrigerant flow direction, enabling the switching cooling, heating, and simultaneous cooling and heating modes; the gas-liquid separator and liquid receiver ensure the stable circulation of the refrigerant, while working in conjunction with the-stop oil return design to guarantee the lubrication of the compressor during long-term low-frequency operation.
Double independent plate heat exchanger (water-side core)
The indoor unit is equipped with two completely independent plate heat exchangers: heat exchanger A corresponds to the radiant circuit (capillary tube ends on floor/ceiling), and heat exchanger B corresponds to the fan coil dehumidification circuit (fan coil unit ends). The refrigerant sides of the two sets of plate heat exchangers achieve different refrigerant evaporation temperatures, and the water sides each correspond to a separate water circulation system, with the water paths being physically completely isolated to prevent cross-flow. One heat exchanger medium-temperature chilled water suitable for the radiant ends, while the other produces low-temperature chilled water for dehumidification, which serves as the physical carrier for dual- water output. Traditional two-pipe indoor units only have one plate heat exchanger and a single water-side circuit, producing only one water temperature at a time, making naturally impossible to achieve parallel dual-temperature water output.
Built-in dual circulation water pump
The indoor unit integrates two variable-frequency circulation pumps, serving the radiant water circuit and the fan coil water circuit respectively. The water pump flow and speed can be independently adjusted by the mainboard without mutual interference. The radiant circuit water pump is responsible for driving the water circulation of the floor heating pipes; the coil circuit water pump drives the water circulation of the fan coil unit. The water pumps are integrated inside the indoor unit body, reducing external water pump accessories and lowering number of potential installation failure points on-site.
Integrated intelligent valve group unit
It contains multiple sets of electromagnetic valves, check valves, and balancing valves, working in conjunction with dual electronic expansion valves and four-way reversing to complete the distribution of refrigerant flow. It achieves automatic switching among six modes: cooling, heating, radiant cooling fan coil dehumidification, radiant heating, fan coil, and simultaneous cooling and heating supply, without the need for additional external valves to adjust water temperature. Traditional two-pipe systems rely entirely on an external three-way valve to mix the cold return water to achieve variable water temperatures, and the main unit itself does not participate in the secondary adjustment of water temperature
Main controller and 485 closed communication collection unit
The main unit's motherboard collects the outlet temperature, return temperature, pressure, and flow rate signals from two water circuits; meanwhile, it receives temperature and relative humidity data transmitted from the thermostats in each room via 485 communication. A data exchange is completed every 10 seconds, after which the calculates the dew point temperature and then inversely controls the refrigerant valve group and the speed of the dual water pumps to dynamically adjust the outlet temperatures of the two water circuits, a closed-loop control through hardware and algorithms. The main unit reserves four water circuit interfaces externally: radiant supply, radiant return, fan coil supply, and fan return, which are the four pipes visible from the outside, hence it is called a four-pipe main unit.
