24 | P a g e
The water system MUST have:
1. A strainer with at least 25 meshes per square inch must be installed on the equipment
inlet water pipe, near the evaporator and heat recovery (if installed). The strainer
prevents solid particles from entering the heat exchanger, as they could damage it or
reduce its heat exchanging capacity.
2. Thermal insulator with thickness at least 10mm must be wrapped around the chilled
water pipe.
3. A bypass pipe between water inlet and outlet of water-side heat exchanger for
cleaning purpose. It is prohibited to flush and clean the water pipes through water-
side heat exchanger.
4. A water flow switch installed at the water outlet of the water-side heat exchanger.
The distance of the level straight pipe between both ends of the flow switch must be
at least 5 times more than pipe diameter. The water flow direction in the flow switch
must be same as that in the water system.
5. A relief valve with an opening pressure less than 1.0MPa installed at the inlet pipe
near to heat exchanger.
6. An automatic water replenishment device to ensure sufficient water in the system.
7. Water pump must be correctly sized and installed at the water inlet of the water-side
heat exchanger to ensure water flow rate is within the recommended range.
8. Sufficient maintenance space.
9. Stop valves must be installed at the water inlet and outlet of the equipment.
10. Manual or automatic air venting device at the system's highest point. Drain device
at the system's lowest point.
11. An auxiliary heater or other heating devices must be installed to ensure that water in
the water system does not freeze when the ambient temperature drops below 0˚C (if
applicable)
12. The chilled water pipe must comply with local piping engineering regulations and
rules.
13. The water used in the water system must comply with related industry standards.
The heat exchanger must be emptied of water during the winter season (if applicable), unless
an appropriate percentage antifreeze mix is added to the water circuit.
If the equipment is installed to replace another, the entire water system is highly recommended
to be cleaned by flushing before the new unit is installed. Regular tests and proper chemical
treatment of water are recommended before starting up the new equipment.
If an antifreeze is added to the water system, machine performance will be lower and water
pressure drops will be greater. All the protection systems at equipment, such as antifreeze, and
low-pressure protection will need to be readjusted.
6.3.3 Water Flow
The design water flow of water system should be same as rated water flow of unit. Of course,
the unit can operate at condition of 70% - 130% rated water flow. However, water flow out of
this range may cause unit alarm or even reduce the unit life expectancy.
6.3.4 Water Volume
It is very important to design the water system with suitable water volume. With too low water
volume, air conditioning terminal device will not be able to operate at stable condition, and then
the user may feel uncomfortable. Moreover, the chiller with lower water volume may be
frequently on/off, and then may cause the chiller alarm, or even damage evaporator and system.
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