A compressor is hard-starting if it struggles to come and stay on. A hard-starting compressor can stop a few times when you first switch on the AC before running. Such motors tend to be noisier than normal. Below are some causes of hard starting.
Each motor has a voltage rating that determines the electrical power it needs to run. The motor won't properly start if it doesn't get enough electrical power. A short circuit, circuit overload, grounding problem, or low power supply from the utility company can all cause a low voltage supply. Increasing the voltage supply to a normal level should get the motor running.
Many motors require a burst of power at first since they use more electricity when starting than when running. Such motors have capacitors, which store electricity and release it in a burst when the AC motor starts.
In such a case, the compressor will struggle to start if the capacitor fails. For example, an overheated and damaged capacitor cannot store and release power equivalent to its electrical rating. Such a capacitor might not start the motor it is supposed to start.
A motor seizes if some of its internal parts stick or suffer damage in such a way that they cannot run as freely as they should. For example, a motor can seize if it's worn and lacking lubrication. Seizing is common with motors that have not run for some time.
A seized motor won't start easily because the stuck part requires a lot of power to get moving. The solution depends on the cause of the seizing. For example, you may get the motor moving again by lubricating it. In other cases, you may have to replace the whole motor.
Lastly, your AC can also struggle to start due to problems with the motor windings. Such problems include:
- Grounded windings that occur if a naked winding touches the motor's casing or core
- Shorted windings that occur when two windings lose their insulation, touch, and cause a short circuit
- Open windings that occur if something severs a winding and cuts off electricity flow
These problems cause hard starting by interfering with the electrical flow and reducing the motor's force generation.
Since numerous issues can cause AC to hard-start, do not try to repair the unit before a proper diagnosis. Otherwise, the problem might reoccur and cause more serious issues. For more information, contact a residential HVAC company near you.