Too much air across the evaporator coil will cause low sub-cooling in the HVAC system. The resulting high compressor discharge temps and will increase refrigerant temps, putting more pressure on the condenser to cool the refrigerant, resulting in lower sub-cooled refrigerant.
In addition to the temperature effects, it will also increase static pressure on the system which increases wear and tear on the blower motor as well as the electric power drawn by the blower which can reduce efficiency of the system.
On the other hand, if your CFM is too high for your room size, it can cause ventilation problems. Too much air results in too little ventilation, which in turn causes high humidity. The excess moisture in the air can then lead to mold and mildew, as well as other problems.
Like we mentioned in the first problem, an oversized AC will often cool your home really fast then shut off. Not only does that wear out your AC components, but it can raise your energy bills too. You see, your AC has several motors that run different components (like the compressor and blower).
Obstructed Vent
One of the most common causes for poor airflow is a blocked vent. To properly heat or cool your home, the air needs to be unobstructed. To see if there are any blocked vents, look by the baseboards or on the ceiling. Furniture, bedding, and the vent damper could all be possible obstacles to the vent.
Reduced airflow can lead to reduced heat exchange in the evaporator coil, causing low superheat. It may also cause the evaporator to freeze due to insufficient warm air passing over the coil. Additionally, the limited airflow can impact the condenser, raising subcooling levels.
An oversized HVAC system cycles on and off more frequently than necessary. This short-cycling leads to increased wear and tear on components, reducing the overall lifespan of the system. It can also result in uneven heating or cooling, creating uncomfortable hot or cold spots in different areas of your home.
Too Hot or Too Cold Air
An oversized HVAC unit can make your home's inside temperature uncomfortable. An HVAC system with excess capacity can heat or cool your home faster, but that speed often results in a couple of other issues. First, your home won't benefit from gradual, even heating and cooling.
Neither oversizing nor undersizing your AC unit is ideal. Both scenarios can lead to issues with efficiency, comfort, and longevity of the system.
If you cook every day or frequently cook for larger groups of people, it's best to choose more CFM.
Not only will this exhaust fan be drawing more energy than necessary, but the extra CFM might cause other issues like drafts or the inability to dry up the moisture still hanging around in the bathroom. And we all know what extended exposure to moisture can do to a bathroom!
What is a good CFM for a leaf blower? A good CFM for most yards ranges between 400-700, depending on the size of the area you need to clear. However, 150-400 CFM should do the trick for smaller yards.
Too much air across the evaporator coil will cause low sub-cooling in the HVAC system. The resulting high compressor discharge temps and will increase refrigerant temps, putting more pressure on the condenser to cool the refrigerant, resulting in lower sub-cooled refrigerant.
A typical central AC unit or heat pump can produce an average of 400 CFM per ton of air conditioning capacity. So, as an example, a 1,200 CFM requirement would mean you need a 3-ton HVAC system.
An air conditioner with BTUs that exceed the recommended square footage in your home may also take on more wear and tear over time because it will initiate its on/off cycle more frequently. It could also create a subpar cooling experience because your AC's compressor may turn off much sooner than it should.
Usually, it is a quick fix, but sometimes the failure can be caused by a much bigger problem. The most expensive part of an AC unit to replace and repair is the air compressor.
Short cycling.
An oversized conditioner will be overly efficient in that it will reach the desired room temperatures too fast, which results in shortened cooling cycles.
An excess of coolant has the potential to cause electrical damage in your vehicle. In some cases, the excess coolant can be accommodated by your engine and exits the engine through the overflow hose. However, it is always a good idea to make sure that your coolant isn't above the maximum fill line.
If your air conditioning system is too big, it cannot completely cool your home. This means that you'll have hot or cold spots throughout your home. An AC system that is too large doesn't run long, so the cool air can't be equally distributed through your home. This causes some areas to be cool while others are warm.
For a 410a refrigerant, the recommended superheat value is typically between 10°F and 12°F, while the ideal subcooling value ranges from 8°F to 12°F. However, these values can vary depending on the specific HVAC system and its requirements.
Answer and Explanation: When you increase air flow to evaporator coil, the rate at which it will absorb heat will increase. Due to high flow rate, the heat transfer efficiency at the coils will deteriorate. Cooling demand will also increase as well.
The temperature that you read with the thermometer should be lower than the saturated condensing temperature. The difference between the measured liquid line temperature and the saturated condensing temperature is the liquid subcooling. Add refrigerant to increase subcooling. Recover refrigerant to reduce subcooling.