Problem #1: Stuck Compressor Motor
If your unit randomly or always trips the circuit breaker that it is plugged into then there is a good chance that the compressor motor has begun to stick.
When compressors first turn on there is a surge of current that runs through them that is much higher that their normal operating current in order to create the needed torque to start spinning the motor.
Once the motor starts spinning this inrush current dies down quickly.
Normally this surge current only lasts a few AC cycles and does not last long enough to trip the circuit breaker.
But, once the motor starts to stick the normal inrush current may not be enough to get the compressor spinning and as a result, the inrush current lasts until the circuit breaker trips.
Why do compressor motors start to stick? It could be that the motor has failed and completely locked up.
However, we have found this generally to not be the case. More than likely the starting torque required to start the motor spinning has increased by only a small amount but just enough to keep it from getting going.
This increase in required torque could just be from normal wear and tear over many years of operation but because we see the problem is relatively new compressors it is likely one of two issues.
First, the manufacturer did a poor job of evacuating all moisture out the refrigeration system before they added the refrigerant to the lines. Moisture in the refrigerant creates an acid that eats away at the compressor.
Secondly, liquid refrigerant should never be sucked in by the compressor, if it is allowed to it washes the oil off of the moving motor components leaving the motor without the required lubrication.
This is a design issue and there really is nothing you can do to resolve it. If either of these conditions is true then your compressor is headed for early death.
However, don’t throw your machine away just yet. There is a solution that can extend the life of your machine for a period of time. Most of the cheap compressors that are used in rolled ice cream machines are known as low starting torque scroll compressors.
This basically means that the manufacturer was too cheap to include what is known as a start capacitor.
A start capacitor looks the same as a motor run capacitor but they do two very different things.
A start capacitor provides the added current and therefore torque to help a compressor get started. They also reduce how long the current inrush period lasts which is good for both the unit and your building’s wiring system.
Problem #2: Poor Air Flow
If your unit seems to run fine but struggles or does not get down to the required setpoint, either quickly or at all, then there is a good chance that your condenser coil is not getting proper airflow.
A typical condenser coil and fan set are shown below. The condenser coil is responsible for rejecting the heat produced by the compressor to the ambient air.
If the condenser coil is blocked by even a small amount of dirt and debris then it cannot perform its function properly.
Most people check for cleanliness on the air exhaust side of the condenser, where the fan isn’t. The problem is most of the dirt accumulation will be on the air intake side hidden behind the fan blades.
ALWAYS UNPLUG YOUR UNIT WHILE WORKING AROUND THE FAN SO IT CANNOT POSSIBLY START WHILE YOUR HANDS ARE AROUND IT.
Use whatever you may have available to clean the dirt out from between the fan blades and the condenser coils.
It is not always easy to get in there but it is critical to keeping your machine running properly and efficiently.