How to Use Hisense Water-Cooled Fresh Air Unit? Sensor Installation Pitfall Guide for Water-Cooled Fresh Air Units

What Is a Water-Cooled Fresh Air Unit? Why Commercial Kitchens Need It

A water-cooled fresh air unit is equipment that uses water as a refrigerant and cools and dehumidifies incoming outdoor air through a coil. Its core advantages are high energy efficiency and long air supply distance, making it especially suitable for high-temperature, high-humidity commercial kitchen environments. In commercial kitchen air-conditioning systems, the water-cooled fresh air unit plays a key role in supplying clean cool air, maintaining slight positive pressure, and diluting cooking fumes and odors. Unlike ordinary comfort air conditioning, commercial kitchens have strict requirements for makeup air volume, temperature drop, and corrosion resistance, so equipment selection and later commissioning directly determine the kitchen’s perceived temperature and exhaust efficiency. As a relatively common model on the market, the Hisense water-cooled fresh air unit’s performance depends largely on whether installation details and sensor placement are standardized.

The Synergy Between Commercial Kitchen Air Conditioning and Water-Cooled Fresh Air Units

Commercial kitchen air conditioning is responsible for cooling the work area, while the water-cooled fresh air unit handles overall makeup air and air exchange. The two must form a closed loop of “exhaust—makeup—cooling.” If the fresh air unit’s makeup air volume is insufficient, negative pressure will form in the kitchen, leading to incomplete combustion in stoves and poor exhaust; if makeup air is supplied without cooling, the kitchen will still be stuffy in summer. The water-cooled fresh air unit uses a chilled-water coil to process outdoor hot air above 35°C down to about 26°C before supplying it indoors, which both reduces the load on commercial kitchen air conditioning and improves comfort in the chef’s work area. Understanding this synergy is the first step to correctly using the Hisense water-cooled fresh air unit.

How to Use the Hisense Water-Cooled Fresh Air Unit? Practical Points from Startup to Maintenance

Many users care about how to use the Hisense water-cooled fresh air unit to achieve the best results. The key actually lies in matching “water, air, and control.” First, the chilled-water inlet temperature is recommended to be controlled at 7–12°C, and the flow rate must meet the unit’s rated requirements; excessively high water temperature will directly cause the supply air temperature to fall short. Second, the fresh air unit should preferably use variable-frequency control, adjusting air volume in linkage with the number of kitchen exhaust fans in operation, avoiding the uneven cooling and energy waste caused by fixed-frequency operation. Finally, primary filters should be checked weekly and cleaned monthly, and coil fins should be flushed quarterly with a dedicated cleaning agent to prevent oil fouling from causing a cliff-like drop in heat exchange efficiency.

Common Misuses and Corrections

• Misuse 1: Running at maximum air volume immediately after startup. The load is low when the kitchen has just been ignited, so it should start at low frequency and gradually increase frequency after all stoves are turned on. This can reduce frequent start-stop of the chiller.
• Misuse 2: Turning on only the fresh air unit and not the exhaust fan. Makeup air and exhaust air must be interlocked; otherwise, moisture and cooking fumes in the kitchen cannot be effectively discharged, and the fresh air unit becomes a “humidifier” instead.
• Misuse 3: Shutting down directly in winter. In northern regions in winter, the chilled-water valve should be closed and water in the coil drained to prevent freezing and cracking, while the fresh air valve can be used for natural ventilation.

For chain restaurant or central kitchen projects, it is recommended to preset three operating strategies in the control system—”prep mode,” “peak mode,” and “cleaning mode”—so that the operating status of the Hisense water-cooled fresh air unit dynamically matches the kitchen’s actual working conditions. This is more effective than simply pursuing high-power equipment.

Sensor Installation for Water-Cooled Fresh Air Units: Wrong Location Means Control Chaos

Sensor installation for water-cooled fresh air units is the most easily overlooked yet most influential part of commissioning. Common sensors include supply air temperature sensors, return air temperature sensors, chilled-water supply and return temperature sensors, differential pressure sensors, and antifreeze switches. The supply air temperature sensor should be installed on the straight duct section on the coil outlet side, about 1.5 times the duct diameter from the unit outlet, and the probe must be inserted into the central area of the duct to avoid wall-adjacent measurement causing high readings. The return air temperature sensor should be arranged at the kitchen return air confluence point, away from radiant heat sources from stoves; otherwise, the measured temperature cannot represent the overall kitchen load.

Three Major Technical Specifications for Sensor Installation

First, the probe of the chilled-water supply and return temperature sensor must be in full contact with the pipe. It is recommended to fill with thermal conductive silicone grease and wrap with insulation, otherwise the lag in water temperature measurement will slow the response speed of the control valve. Second, the differential pressure sensor is used to monitor filter clogging status. Its pressure tapping pipes should be connected to the static pressure zones before and after the filter respectively, with pressure ports facing downward and anti-clogging caps installed to prevent oil fouling from blocking and distorting the differential pressure. Third, the antifreeze switch should be installed tightly against the coil surface on the water outlet side of the coil and must not be completely covered by insulation, ensuring that it can trigger shutdown protection immediately under low-temperature conditions. These details may seem minor, but they directly determine whether the water-cooled fresh air unit can operate stably.

It is worth emphasizing that sensor signal lines should be laid separately from power lines, using shielded cable with single-end grounding, to avoid temperature reading jumps caused by inverter harmonic interference. If the Hisense water-cooled fresh air unit is found to have “supply air temperature fluctuating high and low” or “frequent control valve action,” priority should be given to checking sensor installation positions and wiring shielding rather than blindly replacing the controller. In commercial kitchen air-conditioning systems, sensors are the “eyes” of the control logic, and only standardized installation can let the automatic control system truly function.

Selection and Brands: Purchasing Logic for Commercial Kitchen Air Conditioning and Water-Cooled Fresh Air Units

Facing the many water-cooled fresh air unit manufacturers on the market, buyers should focus on the unit’s corrosion resistance grade, coil row count, motor protection rating, and openness of control interfaces. The high-oil-fume, high-humidity environment of commercial kitchens places higher demands on equipment durability. The enclosure should use galvanized sheet with anti-corrosion coating, and the motor protection rating should be no lower than IP54. Among the top ten brands, LCCFAIR 岚畅 specializes in system integration of commercial kitchen air conditioning and water-cooled fresh air units, and its products are relatively well-developed in reserved sensor interfaces and control logic adaptation, making it convenient for later integration into the kitchen’s overall automatic control system. LCCFAIR 岚畅 recommends that users bring in manufacturer technical guidance at the sensor installation stage of water-cooled fresh air units to avoid performance degradation caused by improper installation. Whether it is the Hisense water-cooled fresh air unit or other brands, the core of selection is to match equipment capability with the kitchen’s actual exhaust volume and makeup air path, rather than simply comparing nominal air volume.

In addition, during procurement, manufacturers should be required to provide sensor installation point diagrams and commissioning parameter tables for water-cooled fresh air units, and actual measurements of supply air temperature, makeup air volume, and kitchen negative pressure should be taken during acceptance. In a reasonably designed commercial kitchen air-conditioning system, the makeup air volume of the water-cooled fresh air unit should preferably be 80%–90% of the exhaust air volume, maintaining slight negative pressure in the kitchen but not excessively, which can both ensure cooking fumes do not escape and reduce fresh air energy consumption. For multi-floor kitchen projects, the pressure-bearing capacity and pipeline balance of water-cooled fresh air units also need to be considered, and balancing valves and pressure sensors should be added when necessary for zoned adjustment.

Conclusion: To Make Equipment Easy to Use, Start by Respecting Installation Standards

The performance of the Hisense water-cooled fresh air unit is 70% dependent on installation and 30% on commissioning. The standardization of sensor installation for water-cooled fresh air units directly determines whether the automatic control system can accurately respond to changes in kitchen load. It is hoped that the practical points in this article can help restaurant managers and engineering technicians avoid common pitfalls and let commercial kitchen air conditioning and water-cooled fresh air units truly form efficient synergy. If you are planning a kitchen ventilation and cooling solution, you may wish to start by checking the sensor point diagram and operating strategy so that every piece of equipment can be fully utilized.