Eight pieces of advice for purchase fan coil units

Do you know how to buy high-quality fan coil manufacturers in China? I have been engaged in foreign trade fan coil units for 13 years. Let me tell you how to choose high-quality fan coil units!

Eighth, the fan coil unit use environment requirements

IX，Trouble shooting of fan coil unit

First, the fan coil unit has two main parameters: refrigeration (heat) quantity and air supply quantity. Therefore, there are the following two ways to choose the fan coil unit.

(1) According to the circulating air volume of the room: the product of room area, floor height (behind the ceiling) and room ventilation times is the circulating air volume of the room. The fan coil model can be determined by using the circulating air volume corresponding to the high-speed air volume of the fan coil.

(2) Selection according to the cooling load required by the room: according to the unit area load and room area, the cooling load value required by the room can be obtained. The model of the fan coil can be determined by using the refrigerating capacity of the room cooling load corresponding to the high-speed air volume of the fan coil.

After determining the model, it is also necessary to determine the installation mode (open installation or installation), air return mode (sending down and down, sending down and down, etc.) of the fan coil and the connection position (left or right) of the water pipe.

Second, the fan coil unit is suitable for use in which occasions:

Fan coil unit is the ideal end product of central air-conditioning, which is widely used in hotels, office buildings, hospitals, commercial and residential and scientific research institutions. The indoor air or outdoor mixed air of the fan is cooled or heated by the surface cooler, and then sent into the room, so that the indoor temperature can be lowered or raised to meet the comfort requirements of people.
The unqualified items of the fan coil are mainly noise and cooling capacity.

Third, what are the main factors for determining and selecting fan coil parameters?

1. Cooling capacity of fan coil unit
   Select products according to the calculated cooling load, but it should be noted that different fresh air supply modes will lead to different cooling loads of fan coil units.
2. Air volume of fan coil unit
   Check the number of air changes according to the room quality requirements. The smaller the air temperature difference, the more air changes, the better the air quality.
3. Air supply and return mode of fan coil unit

The air supply and return modes form the so-called airflow organization, and whether it is reasonable or not directly affects the uniformity and stability of the temperature field and velocity field in the air-conditioned room, that is, the air-conditioning effect is good or bad. Reasonable air flow requires a certain air supply speed to avoid short circuit of air flow and ensure a certain jet length.

4. Other factors

A. the noise index should be controlled below 40dB, and the fan coil unit with high noise should be equipped with noise elimination device, and the resistance value should not be more than 10Pa.

B during installation and construction, pay attention to the quality of heat preservation, the discharge of condensed water, slope direction, pipe fittings and joints, and the cleanliness of the system.

C. The setting method of water system is horizontal system or vertical system. Some construction sites choose vertical system, which can better ensure the discharge of condensed water and ensure the floor height requirement of the room.

Example: For residential and office buildings, when the room area is large, multiple fan coils should be considered. When the room unit area has a large load, and the noise requirement is not high, fan coils with large air volume and cooling capacity can be considered.

Fourthly, the function of fan coil unit components

Fan: driven by the motor of one-way multi-speed low-noise induction system, the fan speed is changed by adjusting the input voltage, so that the air volume of the fan can be divided into three grades: high, medium and low. It is controlled by an electrical switch, and the cooling (heating) amount of the fan coil is adjusted accordingly.

Coil: an air-water heat exchanger made of finned tubes. The refrigerant water (hot water) flows in the tube. Because the temperature of the refrigerant water is lower than the dew point temperature of the air, there is condensed water on the outer surface of the tube, which shows heat exchange in wet condition, and has both heat exchange and mass exchange, thus improving the heat exchange effect.

Condensate pan: it is placed under the coil with the drain pipe, and its function is to receive the water droplets continuously condensed on the coil and discharge them out of the room through the drain pipe.

Air filter: it is placed under the coil with the water discharge pipe, and its function is to receive the water droplets continuously condensed on the coil and discharge them out of the room through the water discharge pipe.

Fifth, the category and model of fan coil unit. Choosing the model is very troublesome. If it’s normal that you don’t understand, you can contact me, and I’ll help you analyze and match the appropriate fan coil unit model.

According to its working principle, the fan consists of two circulation systems: wind circulation and water circulation.

Water circulation: cold water (hot water) from the central computer room circulates in the heat exchanger through water pipes.

Wind circulation: refers to the continuous recirculation of the air in the room where the unit is located, so that the air is cooled (heated) after passing through the cold water (hot water) coil to keep the room temperature constant.

According to the structural form: vertical, horizontal, wall-mounted, card-type, etc.

According to the installation method: surface installation and concealed installation;

According to the water inlet mode: left type and right type;

Thickness: Ultra-thin and ordinary;

According to the presence or absence of condensate pump: ordinary type, luxury type;

According to the static pressure of the unit: 0Pa, 12Pa, 30Pa, 50Pa and 80Pa (external static pressure);

According to the number of tubes: two rows of tubes and three rows of tubes; The more copper pipes, the better the refrigeration effect.

According to the system: two controls and four controls.

Control: Ordinary fan coil units are cooled by cold water in summer and heated by hot water in winter;

Control: It is mostly used in some luxurious places, where hot water and cold water can be taken at the same time, that is, some rooms can be cooled and some rooms can be heated according to needs.

Sixth, does the fan coil need to be cleaned regularly? Need!

When the fan coil is used for a period of 3-5 months, dust and germs will accumulate on the fins and impellers. When the dust reaches a certain thickness, the heat dissipation effect of the fins will be affected, resulting in the room temperature failing to meet the requirements. In addition, the fan coil that has not been cleaned for a long time will breed a variety of germs, which will cause diseases on human respiratory tract. Therefore, it is suggested that the fan coil should be cleaned regularly.

1. Remove bacteria and dust in the air supply and return system to improve indoor air quality;
2. Reduce the wind resistance of VAV air conditioning units, improve the heat exchange efficiency, increase the supply air volume and save energy;
3. Maintain the fan coil system regularly to prolong the service life of the unit;
4. Reduce the operating cost and improve the asset value;

Seventh, which parts of the fan coil units are cleaned regularly? It is necessary to clean these parts.

1. Clean the air inlet filter.
2. Waterway filter cleaning
3. Clean the dust on fins and impellers.
4. Clean the water tray.

Eighth, the fan coil unit use environment requirements

1. The inlet cold water temperature of the fan coil unit should not be lower than 5℃, otherwise it may cause condensation of the unit; The inlet water temperature should not be higher than 80℃ (usually 60℃), otherwise it may cause corrosion of the copper tube of the heat exchanger of the unit.
2. It is suggested that the operating ambient temperature of the fan coil unit should be 16~36℃ for cooling and 10~30℃ for heating. Air relative humidity ≤90%.
3. Fan coil units are only used as comfort air conditioners, and should not be used for special occasions.
4. Do not install the fan coil in the area with corrosive gas.

IX. Trouble shooting of fan coil unit

1. The fan coil unit has small air output and poor refrigeration capacity.

Cause: When the fan is running normally, except for the small intake air volume, it is air leakage in the air duct, which is rarely seen and easily handled. However, the small intake air volume is mostly caused by the blockage of the filter screen of the return air outlet.

Solution: Clean the filter screen frequently. If it is not cleaned in time, dust and sundries will further stick to the coil fins and wind turbine blades, and the fins will be blocked by dirt, which will lead to the decrease of the ventilation capacity of the fan. Dust will also accumulate on the fan impeller, causing the blade angle to decrease, thus reducing the air volume and increasing the fan current. Therefore, it is necessary to clean the filter screen of the return air outlet. Generally, it should be cleaned at least once every quarter, otherwise, the congestion will become more and more serious and the maintenance will become more and more difficult.

2. The fan coil unit is noisy, and the noise increases with the high wind speed.

One of the following reasons:

(1) Poor damping measures during installation and construction, resulting in resonance in operation;

(2) There are foreign bodies in the air duct;

(3) Fan blades are deformed or motor bearings are damaged, resulting in poor dynamic balance. In case of this phenomenon, first check whether the coil supports and hangers are loose, then open the air duct to check and remove foreign matters.

(4) Coil motor does not turn;

(5) The output air volume is normal, and the supply air temperature has deviation;

(6) Equipment and pipelines drip.