The ventilation fan (centrifugal fan or axial fan) is a crucial part of air conditioning unit. Many malfunctions that occur during running of the air conditioning unit are caused by faults related to model selection and installation of the ventilation fan (centrifugal fan or axial fan).
The following faults listed mostly occur in daily use.
1、The specifications of the ventilation fan (centrifugal fan or axial fan) do not meet the design requirements of air conditioning system
If the specifications of the ventilation fan (centrifugal fan or axial fan) do not meet the design requirements, it will not fit installation onto the air conditioning system and performance can’t be optimal. For example, even if the selected air flow and total pressure comply with the design requirements, an incorrect air outlet direction will lead to failure on installation.
It is very necessary to provide correct ordering information according to design requirement of air conditioning system.
2、The deviation for installation does not meet the actual and standard requirement.
The deviations for installation may include displacement of centerline plane, elevation, displacement of transmission pulley width center plane, transmission shaft, and radial displacement between the two shaft centers of the coupling.
Out of the allowable deviation for installation of air conditioning fans does not meet requirements of project quality standards, which will not be accepted for handover. These deviations will increase operating noise and current, and will also reduce the service life of the equipment.
To make sure deviation within specified range requires operators strictly to limit deviation adhere to the requirements of the specifications and do thorough adjustment after installation.
Before installing the fan, it is necessary to verify the fan’s product name, model number, serial number, transmission method, rotation direction, and air outlet position according to the design requirements. Additionally, inspect the fan’s exterior appearance. Once these requirements are met, the fan can be installed in accordance with the relevant standards.
3、The blade angles of the axial fan assembled on-site are inconsistent with each other.
The air pressure and flow of an axial flow fan depend on the angle of the fan blades. If the angles of the blades do not conform to the specifications outlined in the technical documentation during on-site assembly, it will affect the air pressure and air flow at the fan’s outlet. Inconsistent blade angles during assembly will cause pulsation phenomena in the running.
Before assembly, it is essential to understand the angular requirements for blade assembly as outlined in the technical documents. During assembly, the angles of each blade should align with the same reference mark to ensure uniform clearance between the impeller and the cylinder. Once the blade angles are consistent, the blades can operate normally in the same plane.
4、The fan transmission device lacks a protective cover, and the motor in open air has no rain cover.
The belt drive device between the fan and the motor in open air without a protective cover violates safe operating procedures during both trial and long-term operation.
Fans installed in open conditions such as rooftops are highly susceptible to rain and moisture damage, which can cause short circuits and burnout if their motors lack protective rain covers.
The protective cover of the transmission device must be installed before the equipment trial run for the trial operation. For electric motors operating in open field conditions, the rainproof cover should be installed after the fan is assembled to prevent the motor from rain and moisture during construction and running.
