If All Fan Coil Units Are Shut Down, How Should The Water System Return Water?

If all fan coil units are shut down, how should the water system return water?

The fan coil unit water system is a relatively complex system, including the problem of water supply and return to the air conditioner main unit.

So, if all fan coil units are shut down, how should the air conditioning water system return water?

The fan coil unit water machine is the system that uses water as a medium to exchange heat with the air to achieve temperature regulation. The host has certain return water volume requirements to prevent the water temperature of the air conditioner from being too low in summer and damaging the unit.

In addition, excessive internal pressure in the air conditioning water system may cause damage to system components or abnormal operation, thus affecting the normal operation and service life of the unit.

Therefore, a pressure relief valve will be installed on the waterway system of the fan coil water machine system. Commonly used pressure relief valves mainly include the electric three-way valve on the fan coil unit and the pressure differential bypass valve on the water supply and return pipe of the air conditioner main unit.

Fan coil installation use cases
Fan coil installation use cases

When the fan coil unit is turned off, the water system return water will face two situations:

First, there is no electric two-way valve installed on the fan coil. Even if the fan coil is closed, the water in the air conditioning water system will be driven by the water pump, pass through the fan coil, and return to the air conditioning main unit through the return pipe.

A Chinese manufacturer of horizontal concealed fan coil units, providing OEM&ODM services.
A Chinese manufacturer of horizontal concealed fan coil units, providing OEM&ODM services.

Second, if an electric two-way valve is installed on the fan coil unit, there are two options for water return in the system:

1. According to the form of an electric two-way valve and an electric three-way valve, the quantity is installed in a ratio of 2:1.

When the fan coil is closed, the water in the system will branch back to the air conditioner main unit from the third branch of the electric three-way valve.
If all fan coil units are shut down, how should the air conditioning water system return water?

2. According to the form of an electric two-way valve + pressure difference bypass valve, a pressure difference bypass valve is installed on the air conditioner water supply and return main pipe. When the fan coil is closed, the pressure difference bypass valve will automatically open according to the system pressure change. , balance the supply and return water pressure, and maintain system stability.

Electric two-way valve of fan coil
Electric two-way valve of fan coil
Electric two-way valve of fan coil1
Electric two-way valve of fan coil
Electric two-way valve of fan coil
The electric two-way valve of fan coil
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