1 Air Conditioning Air System problems

2 The primary problem that can occur in an air system is the reduction in airflow. Air handling systems do not suddenly increase the amount of air across the coil. The refrigeration system does not increase in heat transfer ability. The primary problem that can occur in an air system is the reduction in airflow. Air handling systems do not suddenly increase the amount of air across the coil. The refrigeration system does not increase in heat transfer ability.

3 The first step in checking for air system problems is to take a temperature reading across the evaporator coil. Take a temperature reading of the return air and the supply air. The difference between these two temperatures is referred to as the “temperature drop”. The first step in checking for air system problems is to take a temperature reading across the evaporator coil. Take a temperature reading of the return air and the supply air. The difference between these two temperatures is referred to as the “temperature drop”.

4 A acceptable temperature difference is between 18 – 20 degrees. A sling psychrometer is used to measure the return air dry bulb and wet bulb temperature needed to determine the relative humidity. These measurements will help to determine if the problem is a result of improper airflow or a refrigeration system problem. A acceptable temperature difference is between 18 – 20 degrees. A sling psychrometer is used to measure the return air dry bulb and wet bulb temperature needed to determine the relative humidity. These measurements will help to determine if the problem is a result of improper airflow or a refrigeration system problem.

5 If the actual air temperature drop is greater than the required temperature drop, then the air quantity has been reduced or slow down. This could be due to dirty air filters, a dirty evaporator coil, a problem with the blower, or an unusual restriction in the duct work. If the actual air temperature drop is greater than the required temperature drop, then the air quantity has been reduced or slow down. This could be due to dirty air filters, a dirty evaporator coil, a problem with the blower, or an unusual restriction in the duct work.

6 Air Filters The most common problem of air failure. Always check first. Air filters of the throwaway type should be replaced at least once a month. The most common problem of air failure. Always check first. Air filters of the throwaway type should be replaced at least once a month.

7 Blower motor and Drive Check the blower motor and drive in case of a belt driven blower to make sure that blower motor and blower bearings are properly lubricated and operating freely. If belt driven, check the belt for dry rot and cracks. Cracked or heavily glazed belts must be replaced. Check the blower motor and drive in case of a belt driven blower to make sure that blower motor and blower bearings are properly lubricated and operating freely. If belt driven, check the belt for dry rot and cracks. Cracked or heavily glazed belts must be replaced.

8 Heavy glazing can be caused by too much tension on the belt, driving the belt down into the pulleys. Proper adjustment requires the ability to depress the belt midway between the pulleys approximately 1 inch. Blower wheel should be clean. Dirt accumulation can sometimes fill in the area on a cupped blade allowing it to spin freely but substantially reducing the airflow. Heavy glazing can be caused by too much tension on the belt, driving the belt down into the pulleys. Proper adjustment requires the ability to depress the belt midway between the pulleys approximately 1 inch. Blower wheel should be clean. Dirt accumulation can sometimes fill in the area on a cupped blade allowing it to spin freely but substantially reducing the airflow.

9 If the wheel is dirty or has mold build up, it must be removed and cleaned. Attempting to clean a wheel in place is never recommended. Do not try brushing only, because a poor cleaning job will cause an imbalance to occur on the wheel. Extreme vibration and noise will result. Other damage may also result, such as damage to the motor itself. If the wheel is dirty or has mold build up, it must be removed and cleaned. Attempting to clean a wheel in place is never recommended. Do not try brushing only, because a poor cleaning job will cause an imbalance to occur on the wheel. Extreme vibration and noise will result. Other damage may also result, such as damage to the motor itself.

10 Dirty Blower Wheel and mold growth

11 Unusual restrictions in duct work Placing furniture or carpeting over return grilles reduces the air available for the blower to handle. Shutting off air to unused areas will reduce the air over the coil. Covering a return grill to reduce the noise from the unit itself may reduce the noise, but will drastically affect the operation of the system by reducing air quality. Placing furniture or carpeting over return grilles reduces the air available for the blower to handle. Shutting off air to unused areas will reduce the air over the coil. Covering a return grill to reduce the noise from the unit itself may reduce the noise, but will drastically affect the operation of the system by reducing air quality.

12 The condition of the air grills and vents can indicate potential problems. Water stains can be caused by improper humidity conditions. Soot stains may be a result of an improper functioning furnace exhaust leaking back into the air supply line. The condition of the air grills and vents can indicate potential problems. Water stains can be caused by improper humidity conditions. Soot stains may be a result of an improper functioning furnace exhaust leaking back into the air supply line.

13 Soot Stain on Supply Register

14 The collapse of the return air duct system will affect the entire duct system performance. Air leaks in the return duct will raise the air temperature and reduce the temperature drop across the coil. Look for pinched ducts, sharp bends and unnecessary duct length. The collapse of the return air duct system will affect the entire duct system performance. Air leaks in the return duct will raise the air temperature and reduce the temperature drop across the coil. Look for pinched ducts, sharp bends and unnecessary duct length.

15 Deteriorated Flex Duct and Restrictions

16 Other major problems that need to be fixed ASAP!

17 Sharp Bends in flex duct and excessive lengths that need to be fixed

18 Iced up Evaporator

19 Iced up Heat pump. Not going into defrost.

20 Covered Condenser Coils

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