No matter which end solution you choose, the overall installation process for the Five-Constant host is the same. It's divided into eight stages: preliminary survey and design, basic construction, equipment hoisting, pipeline laying, electrical wiring, pressure testing and flushing, system commissioning, and final acceptance.
Preliminary survey and design plan (the most important step before installation)
Many projects run into problems later on because the design was simplified in the early stages. Before construction starts, HVAC engineers need to visit the site to survey the building: wall insulation, airtightness of doors and windows, apartment orientation, ceiling height, local climate parameters, and calculate the heating and cooling loads for each room.
Load calculation
Calculate the cooling load, heating load, and moisture load for each room to determine the capacity of the main unit, the type of terminal units, pipe diameters, and the number of loops for the manifold. You can't just estimate the size of the main unit based on experience. If the unit is oversized, it will turn on and off frequently and use more energy; if it's undersized, it won't be able to reach the set temperature and humidity in extreme weather.
Plan confirmation
Based on the owner's decoration style, ceiling height, and budget, choose the end setup, draw detailed piping construction diagrams and electrical control drawings, and mark the pipeline routes, equipment locations, and thermostat positions.
Spot Planning
Decide on the placement of the five-constant main unit. Prioritize putting the unit on a well-ventilated balcony or equipment platform that meets the weight requirements; avoid bedroom exterior walls to reduce noise impact; leave some space for maintenance, with at least 30cm around the unit for service access.
Basic construction stage (with renovation and electrical/plumbing work starting at the same time
The Five-Constant System is part of hidden work and needs to be coordinated with civil, water, and electrical construction.
Surveying and setting out
According to the construction drawings, mark the pipeline routes, the locations of the manifolds, the thermostat back boxes, and the positions of the end devices.
Insulation construction
For floor radiation, you need to lay insulation boards and reflective film first; for ceiling radiation, make sure the ceiling is insulated properly; all wall penetrations should be pre-drilled and fitted with sleeves.
Reserved control line
Pre-install communication signal lines between the thermostat, main unit, and fresh air dehumidifier in advance. Keep strong and weak electrical wiring separate, and shield the signal lines to avoid interference.
Hoisting and securing the main unit and terminal equipment
Fixed Heng-Wu outdoor unit
Level the equipment platform, add vibration pads, secure the main unit. The vibration pads are used to reduce the vibrations from the compressor, preventing low-frequency noise from transferring to the walls. Keep the main unit level to ensure smooth oil return from the compressor.
End device hoisting
All fan coil units and fresh air dehumidifiers are mounted using vibration-damping hooks, with maintenance access provided; the spacing of the clamps for the ceiling radiant pipes meets the standards to prevent the pipes from bending or sagging.
Manifold installation
Manifold water distributors should be installed first in equipment rooms and the dry areas of bathrooms, mounted vertically, with space left for maintenance. Each branch should have a valve, filter, and flow meter installed.
Water and pipe installation work
The pipes are divided into supply pipes and return pipes, with red markings for supply and blue for return, making them easy to tell apart.
Pipe selection
For a five-constant system, high-temperature and low-temperature resistant PERT or PPR pipes specifically for HVAC are recommended. These pipes are tough and won't crack easily with hot and cold cycles.
Pipe slope and securing
Use large bends for pipe turns to reduce local resistance; pipe clamps are spaced according to regulations; all cold water pipes are wrapped with closed-cell rubber and plastic insulation, with sealed joints to prevent condensation.
Pipeline connection
Hot melt welding ensures no leaks at the joints; after the pipeline is connected, flush it first to remove any welding slag and debris inside the pipes, preventing impurities from entering the main heat exchanger and causing blockages.
Electrical System Wiring Installation
The five-constant system is an electromechanical system, with the electrical part divided into power lines and communication/control lines.
Host power supply
The host has a separate circuit with a matching air switch and grounding protection. The host's power can't share a circuit with other high-power appliances.
Control signal lines
These are the communication lines between the indoor thermostat, fresh air dehumidifier, and main unit controller. Connect them point-to-point according to the drawings, make sure the terminals are tightened, and label them properly.Keep the signal wires and high-voltage cables laid separately to prevent signal interference, which could mess up the temperature and humidity readings.
Grounding protection
All metal equipment casings are reliably grounded to ensure electrical safety.
Hydrostatic pressure testing and pipeline flushing test
After all the piping is installed, you have to do a water pressure test. This step is key for spotting any potential leaks, so don't skip it.
Water pressure test
Pressurize the hot and cold water pipes to 0.8-1.0 MPa and keep the pressure steady for 24 hours. It's considered okay if the pressure drop is less than 0.05 MPa. Check that all joints have no leaks. Pay special attention to the ceiling radiant pipes, because once the ceiling is closed later, fixing any leaks will be really expensive.
Pipeline flushing
After the pressure test passes, flush the entire water circuit to clean out any welding slag and sediment inside the pipes, until the water runs clear with no debris. This prevents dirt from getting into the main unit's heat exchanger or fan coil and causing blockages. Once flushing is done, install a Y-type filter at the front end of the water distribution unit and regularly filter out impurities.
System integration (the core part of installing the Five-Constant system)
After suppressing, flushing, and finishing the renovations, we move into the system debugging stage. For a regular dual supply system, only the temperature is debugged, while the five-constant system must complete the temperature and humidity linked debugging.
Standalone debugging
Start the Wuheng main unit alone, check the running status of the compressor and water pump, see if the pressure and water temperature are normal; test the fan coil and fresh air dehumidifier separately.
Hydraulic balance commissioning
Adjust the branch valves of the manifold one by one, calibrate the flow at each terminal according to the design flow, and solve the problem of insufficient flow at the far end.
Temperature and humidity linkage logic settings
set the host dew point protection parameters, adjust the start/stop thresholds for the fresh air dehumidifier, test the host automatic water supply temperature rise under high humidity conditions, and verify the anti-condensation protection function.
Noise test
Run the whole system and check the indoor noise. The goal for the five-constant system is an indoor noise level ≤35dB, meeting the constant quiet standard.
Completion Inspection and Handover Training
After debugging meets the standards, proceed with the final acceptance inspection, checking the drawings, pipeline labels, pressure test records, and commissioning reports. Upon delivery, train the owner on basic system operations: thermostat settings, daily on/off, filter cleaning, and simple troubleshooting. Also, inform them about the maintenance schedule, regular filter cleaning, annual seasonal maintenance of the main unit, and other precautions, and hand over the complete as-built drawings.
