The compressor is among the most critical components in your HVAC systems. This doesn’t mean the other parts aren’t essential, but in terms of functioning, the compressor probably does the heaviest lifting to ensure that your home is cooled or heated properly. Hence, you must ensure that it is functioning in the optimal state. This can be done by ensuring the AC repair company checks the compressor when they come for a maintenance service. They should inspect, clean, and lubricate the component. However, there are issues, especially refrigerant-related problems, that might silently affect the functioning of your compressor. One of these problems is refrigerant floodback.
Also called the compressor floodback, refrigerant floodback is a common reason for failure in many HVAC and refrigerating systems. It arises whenever an uncontrolled refrigerant in a liquid state enters the compressor when the HVAC unit is running. In an HVAC system, the coolant leaves the evaporator and enters the compressor in a superheated vapor state. However, if the coolant isn’t entirely vaporized in the evaporator, part of it will be sucked into the compressor in a liquid state, resulting in refrigerant floodback. Unless you hire an experienced AC repair company, you could misdiagnose this as a compressor issue, although the compressor doesn’t cause it.
Accumulating dirt on the evaporator coils, a buildup of ice on the coils due to poor ventilation, failed fan motor, and a damaged evaporator fan belt are some of the problems that might cause refrigerant floodback. All these are issues that an AC repair company can address during a maintenance visit to prevent further problems like floodback. Incorrect defrost cycles or even less effective defrosting methods might make the ice accumulate over the coils, resulting in coolant floodback.
Did you have a refrigerant leak and hire an AC repair company to charge the unit? If the technicians from the company were inexperienced, they could have done more harm. Overcharging the coolant or even capillary tubes that are too large or short means you will need a larger volume of the coolant to enter the evaporator coils. Unfortunately, this means that the boiling point of the coolant might never be reached. Since the boiling point will not be reached, the refrigerant will never turn to a superheated vapor state before entering the compressor, resulting in refrigerant floodback. However, you can prevent floodback by installing correctly working expansion valves.
As explained above, installing expansion valves can help prevent refrigerant floodback. However, the valve must be working correctly. Since they regulate refrigerant flow rate, misadjusted or malfunctioning valves might result in refrigerant floodback. Thus, ensure they are inspected when the AC repair company sends a technician for a maintenance visit.
In the Off Cycle, the pressure difference might arise between the coolant vapor/liquid within the HVAC system and the lubricating oil in the crankcase. Since vapors and liquids flow from high-pressure to low-pressure areas, the coolant migrates into the crankcase, the lowest pressure point in the system. When you turn on the compressor, the refrigerant settling under the oil at the bottom of the crankcase starts boiling and vaporizes. Small oil particles enter the vapor refrigerant, resulting in compressor failure. This issue can also be caused by liquid slugging at the HVAC startup. Your AC repair company can prevent refrigerant floodback and migration by installing a suction accumulator in your HVAC compressor system.
Whenever a technician from your reliable AC repair company comes for a maintenance visit, they will check whether the compressor and other mechanical parts are lubricated. Once the coolant enters the crankcase, it becomes only a matter of time until your AC compressor is seized. Since part of the oil used for lubricating the various mechanical parts is entrained by the coolant and later pumped by the compressor into the system, there is a decline in oil levels within the crankcase. This means that the compressor will not be lubricated properly.
As mentioned above, oil particles are entrained by the coolant. Whenever this happens, they will increase in density of the coolant charge. As the refrigerant is pumped via the cylinder, a higher-than-required pressure develops in the crankcase. This additional load makes the compressor motor draw more current, resulting in unwanted inefficiencies. Further, a motor that draws more current might cause a compressor burnout.
The oil entering the HVAC system also might coat the inner surfaces of the tubes and valves, further reducing the system’s efficiency. Faulty valve assemblies, clogged capillary tubes, compressor overheating, repeated tripping of the breaker, and broken valves are other issues that this problem could cause. You should prevent refrigerant floodback by having the AC repair company check the refrigerant levels and quality when they visit for maintenance.
Whenever you turn on the HVAC system and the compressor starts up, the pressure of the oil-refrigerant mixture inside the crankcase drops suddenly. Since a lower volume of the liquid coolant is needed to saturate the oil, the rest of the coolant expands and evaporates into vapor. The oil-refrigerant mixture will boil quickly due to the refrigerant’s abrupt expansion, producing excessive foaming that is usually associated with compressor floodback. Consistent foaming should be considered a sign of refrigerant floodback because oil can occasionally create some foaming at startup. Another obvious indicator of floodback is a frosty, sweaty, or cold crankcase. Hence, when you notice either, you should immediately turn off the HVAC and call an AC repair company.
Do you need your compressor inspected or the quality and volume of the refrigerant tested? Contact us at Pitzer’s One Hour Air Conditioning & Heating of Mohave County today for a professional service.
Check our most recent blog on this topic here.