Phenomena: In some projects, the noise of room air coils is too high.

Reason:

1) At present, the actual noise level of all kinds of fan coil units at home and abroad is generally high, and the lower level is only a small part.  Domestic fan coil units have reached the international level in terms of noise.

2) The indoor noise level is different due to the different installation positions and configuration modes of fan coil units in guest rooms.  According to the relevant units, the fan coil units in different installation locations have been measured. When the fan coil units are operating at high speed, the noise floor limit is NC-45 and the lower limit is NC-35.  The upper limit value for low speed is NC-40 and the lower limit value is NC-25.

Countermeasures:

1) The installation position of fan coil shall be considered according to the room grade when designing and selecting.  When the bedroom with high requirements is concealed, noise elimination treatment can be carried out in the air duct from the outlet of the fan coil to the air supply outlet of the room.  Vertical fan coil units should be located far away from beds and tables, and noise elimination devices can also be added to the air outlets.  For general requirements, horizontal or vertical fan coil units with medium noise level can be selected.

2) Use the room to store cold.  The room temperature will be reduced to 23~24℃ during the day, and the indoor temperature will not be too high even if the fan coil is turned off at night.

Points for Attention in Designing Fan Coil System

(1) Condensate drain pipes should be set up nearby to drain water, which can shorten the distance of horizontal drainage and reduce the risk of water collection and dripping due to insufficient slope of drain pipes.  The pipe diameter of the drain pipe led out from each fan coil should be φ20, while the size of the drain riser and main pipe should be larger.

(2) Water collecting plates shall be made under the manual and electric water valves on the fan coil and cold and hot water pipes.  The water collecting plate can be communicated with the fan coil water collecting plate, or the manufacturer can be required to lengthen the original water collecting plate to ensure that condensed water at joints such as valves can be discharged along the water collecting plate.  But also to do a good job of external insulation to prevent secondary condensation water.

(3) There should be an inspection opening, its location and size, and the specific project should be closely coordinated with the building and settled through negotiation.  Attention should be paid to the convenience of assembling and disassembling the small suspended ceiling at the installation of fan coil units, as this is necessary for the use and maintenance of fan coil units.

(4) Filter screen shall be installed at the air return port to protect the fan coil from cleaning, otherwise the heat exchange efficiency will be low and fast.

(5) Pay attention to the fan coil unit with high static pressure when connecting to the fan coil unit.

(6) The installation position of the water valve shall be indicated to avoid reverse connection.  At present, the water valves in many projects are installed reversely. It is necessary to remind the power supply not to connect the "N" line incorrectly. If the "N" line is connected incorrectly, the motor will be burnt out.