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How to Check and Repair Air Conditioner Fan Motor on AC Unit

By Susi | Published on Nov 02,2015

1. Completely clean condenser fins and ensure the condenser fins is clean and arranged in neat rows .

2. Check the fan motor is securely fastened and make sure it run smoothly with no abnormal sound; check the fan blades ,wind speed whether they are in a good condition; replace outdoor fan bearings.

3. Check the fan motor pressure relay

4. Detect outdoor fan winding resistance, current, fan insulation performance

1.Condenser fan

Functional role: Condenser fan is designed to cool the air conditioning unit to ensure the proper air conditioning performance. If a faulty condenser fan motor which fails to froze refrigerating fluid can cause the abnormal performance and operating noise.

The purpose of replacement: to reduce the fan noise and operating costs. Smooth running condition and improve condensation effect.

Steps for condenser fan motor replacement: take down the grille bolts and open the junction box, then remove the wiring and the fan, and then replace a new fan motor, and then connect the power and the wire mesh cover and last tighten bolts.

2. The fan motor bearings

functional role: fans are aimed to enhance air circulation in order to better condenser cooling function. If the fan motor bearing is break, the fan is running at imbalance, causing noise, or the fan bearing is stuck causing fan burned.

The purpose of replacement: To reduce fan noise and lower operating costs and to make motor running smoothly after condensation improved significantly.

Steps for fan motor bearing replacement: Dismantle the fan grille, and use a hex wrench to remove the jackscrew on the fan, then remove the fan blades with a special wrench, remove the fixed motor screw with wrench, then you can get the motor , open the cover of both ends to remove the bearing with special wrench, then replace new bearings and put cover on it, with screw fixed. Install the motor and new new blade. Last tighten the jackscrew and install fan grille.

3. Pressure Controller

Functional role: switch-type pressure relay is used to check the elasticity of spring. when the programmed pressure reaches a certain level, it can quickly switch on and off. Set value of pressure relay is 15-18BAR. If there is something wrong with pressure controller, the fan motor can not be started and stopped properly, which can cause system instability and will bring a high or low pressure .

the purpose of replacement of pressure controller is to enable the motor unit start and stop properly.

Steps for replacement: Turn off the power switch and remove the control line, then replace a new compression joint quickly and fix pressure controller, and connect the control line and then turn on the power .

4. Speed Control panel

Functional role: adjust and control the start-up and shut-down of condensation fan. If the speed control board is faulty , one or several condenser fan motors can not work and result in high pressure in condenser and the system, paralyzing the unit.

The purpose of replacement: to ensure the unit condensate system work properly..

Steps for Speed Control panel replacement: Close condenser power switch, remove the wires and control the switch line to open the lock button and replace the control panel. And then connect the control switch line and put up the power cord and the rain cover, and last turn on the power switch.

5. Pressure relief valve

Functional role: Protect condensation system and the high pressure compressor valves. If the release valve is faulty or does not work, it will result in over high-pressure of compressor or compressor burning.

Steps for Pressure relief valve replacement: Let out the refrigerant and screw off the valve and replace it and refill refrigerant after being evacuated.


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