How to troubleshoot if the air conditioner fan is running but there is no obvious air supply?

When the air-conditioning box fan shows that it is running but there is no obvious air supply, you should first confirm the actual rotation and effective operation feedback, and then check whether the air path is connected, whether the air valve is open, and whether the filter material and protective packaging are blocked. You cannot assume that the fan has established the required airflow just by looking at the operating icon on the control screen.

First confirm whether the command, feedback and actual rotation are consistent

'Run' on the control screen may only mean that a command has been issued, or it may be feedback from the inverter or contactor, but does not necessarily mean that the fan has reached the design speed. When troubleshooting, first check the start command, actual speed or effective operation feedback and alarm status, and then have professionals confirm the fan steering and transmission status according to the equipment instructions. When electrical or rotating parts are involved, isolation and professional operation requirements should be implemented, and the door should not be opened to touch the parts while the power is on or rotating.

For the definition of commands, operation feedback and fault points in the control point table, please refer toWhat point tables need to be provided before the air-conditioning box is connected to the building automation system? . For DC fan drive and signal matching, please refer toWhat driving conditions need to be matched when using a DC fan in an air-conditioning box?。

Step-by-step verification along controls, equipment and air paths

The order of troubleshooting can be divided into three levels: the control layer looks at whether commands, feedback and alarms are consistent; the equipment layer looks at the status of fans, motors, shock absorbers and transmission components; the air path layer looks at air valves, air ducts, filters and temporary blocking. If any of the three layers is blocked, it may appear as 'the fan is spinning but there is no wind.' First confirm which layer is disconnected and then decide the next step, which is more targeted than directly increasing the speed.

When the total air volume of the system is insufficient, check the measurement first or increase the speed first. Please refer toIf the total air volume of the air conditioning box is insufficient, should I check and measure it first or should I increase the speed first? . For the relationship between fan operating point and efficiency range, please refer toWhy should we check the efficiency range when selecting air-conditioning box fans?。

The damper and system modes must be eliminated first.

The positions of the fresh air valve, return air valve, air supply valve and fire damper will directly affect whether the air path is connected. The control screen shows that it is open, which does not mean that the valve is actually in place. Valve actuator failure, connecting rod falling off, valve shaft jamming or incorrect mode setting may cause the air path to be closed or at minimum opening. During the inspection, you should confirm the actual position of the valve and check whether the current operating mode allows air supply.

For the difference between the opening of the fresh air valve and return air valve and the actual air volume, please refer toCan the opening of the fresh air valve and return air valve directly represent the air mixing ratio? . Check whether the air path in the mixing section is smooth. Please refer toHow long is the air mixing distance required in the mixing section of the air conditioning box?。

Filters and temporary blockages are common choke points

For newly installed or renovated units, the filter protective packaging has not been removed, the transportation seal has not been removed, and the temporary blind plate of the air duct has not been removed, which may cause air path obstruction. If the filter is installed in the wrong direction, has inconsistent specifications, or the pressure difference is too high, it will also limit the air volume. During the inspection, the installation status of the filter and the pressure difference reading should be checked to confirm that the transportation protection has been completely removed.

How to remove the transportation protection of the air outlet and pipe joints, please refer toHow should the air vents and pipe joints of air-conditioning boxes be protected before leaving the factory for transportation? . For filter classification configuration and pressure difference monitoring, please refer toHow to configure the primary-efficiency and medium-efficiency filters of air-conditioning boxes in different stages? . The internal resistance composition can be referred toWhat functional segments should be included in the internal resistance of the air conditioning box?。

Check fan steering, transmission and air pressure

Wrong direction of the fan, slippage or breakage of the belt, unbalanced dust accumulation on the impeller, and displacement of the shock absorber may cause the fan to rotate but fail to establish effective wind pressure. The inspection methods for direct-coupled fans and belt drives are different and should be checked according to the equipment instructions. Static pressure or differential pressure readings at the fan outlet and inlet can help determine whether the fan is building pressure.

For the fan pressure budget and external static pressure caliber, please refer toHow is the total pressure of the air conditioning box fan determined by the internal resistance and external demand? andWhat is the difference between static pressure, total pressure and static pressure outside the air conditioner box? . If the fan outlet connection space is limited, it may also affect the actual performance. Please refer toCan the length of the horizontal air conditioning box be reduced when there is insufficient plane space?。

Record the phenomenon before deciding on the next step

Record whether there is no wind at all ends or a certain branch, whether the equipment suddenly starts up for the first time or after running, and retain the control and alarm data at that time. After confirming that there is still no wind after the passage and equipment are working, you should stay at the evidence verification and it is not appropriate to directly increase the speed or shield protection. Maintenance personnel will then further check the performance and installation status.

For condition checks before starting the machine for the first time, please refer toWhat conditions need to be checked before the air-conditioning box is turned on for the first time? . How to change the debugging sequence from stand-alone to system linkage, please refer toHow to change the debugging sequence of air conditioning box from stand-alone unit to system linkage? . Records should be able to correspond to the equipment number, date, participants and each conclusion.

Aili industrial supporting equipment

When providing feedback to Aili Industrial, providing the equipment number, start-stop screen, actual speed and damper status is more helpful in locating the problem than describing 'very little wind' alone. Aili Industrial can match the fan, motor, damper, filter and control configuration in the delivery materials; the manufacturing end covers independent research and development and production of motors and fans, control systems, sheet metal, air filters and complete machine assembly. Fan operation feedback, damper interface and filter section status can be checked in the same package.

Product form can be viewedAir handling unit andFan box page; clean air supply package can be combinedFFU fan filter unit andEFU equipment end fan filter unit verification; multiple equipment linkage can understandMatching method of FFU computer group control system ; terminal particle filtering can be combinedHEPA/ULPA filter confirmation; when it comes to gaseous pollution control, you can communicate separatelyChemical filter solutions. The specific air volume performance, applicable conditions and delivery scope still need to be verified based on the corresponding configuration data and on-site working conditions. The actual effect is subject to on-site air volume measurement and debugging results.

Submit project parameters:https://ailigy.com/contactus.html

Related questions and answers

The control screen shows that the fan is running, why is there still no wind?
The screen may only reflect commands or inverter feedback, but does not mean that the fan has reached the design speed, nor does it mean that the air path is connected. Actual rotation, damper position and filter status need to be verified.

The newly installed unit has no air supply, what should I check first?
First check whether the transportation seal and protective packaging have been removed, then check the actual position of the air valve and the installation direction of the filter, and finally check the fan rotation and operation feedback.

Can Aili Industrial help troubleshoot the problem of no air supply from the fan?
The equipment number, control record and air path status can be combined to assist in positioning. Specific processing must be carried out by on-site professionals according to the equipment instructions.

Related articles

1. If the total air volume of the air conditioning box is insufficient, should I check and measure it first or should I increase the speed first?

2. What conditions need to be checked before the air-conditioning box is turned on for the first time?

3. How should the air vents and pipe joints of air-conditioning boxes be protected before leaving the factory for transportation?

4. How to change the debugging sequence of air conditioning box from stand-alone unit to system linkage?

Key points for selection and acceptance inspection