Post by Admin on Aug 5, 2022 17:22:36 GMT -6
It's the Dog Days of Summer and we all love the Cool Air that Air Conditioning Supplies but do you know how it works???
Understanding How Air Conditioning Works will help you understand the Importance and How to Maximize Cooling.
First lets start with the Law of Heat Transfer, Heat always moves to a cooler surface. Fire up your stove and Put a Pan of Water on the Stove. The Heat from the Flame or Electric Element transfer to the pan first because it is cooler. Then add water and the Pan transfer heat to the water and after a while it begins to boil. Next insert a metal spoon into the water and the heat transfers from the water to the spoon. Then when you grab the metal spoon your hand is colder and it burns your hand. Heat always transfers to colder surface. The same happens in an Air Conditioning System or Cooling System.
Now lets talk Air Conditioning...and it doesn't matter Tractors, Home, Truck, Car....all systems use the same Basics & Principals of Air Conditioning
#1 Air Conditioning Does NOT Cool it Removes Heat!
#2 Air Conditioning Cooling is limited by Outside Temperature (Air Conditioning can remove approximately 15° to 25°F from Outside Temperature)
So How does Air Conditioning Work if it doesn't Cool...
In the Above Picture you can see the Basic Components of an Air Conditioning System. The Compressor takes Low Pressure/High Heat Freon Gas and Compresses it into High Pressure/High Heat Gas that enters the Condenser that is normally located in front of the Radiator. Since air is blowing through the condenser from the engine fan or auxiliary condenser fan the condenser is a cooler surface than the Freon Gas Temperature and Heat Exchange happens as the condenser fins absorb the heat from the Freon Gas. The Air from Fan pulls air that is cooler and removes the heat from the condenser, thus cooling the Freon too. During this process of Heat Exchange in the condenser the Freon changes from a High Pressure gas to High Pressure Liquid. After it leaves the Condenser it typically enters as Receiver/Dryer as a High Pressure Liquid. The Receiver/Dryer acts as Storage Tank and Also Removes Moisture from the Freon. Once it travels from the Receiver/Drier the High Pressure/Liquid Freon moved into one side of the Expansion Valve that converts the High Pressure/Liquid to Low Pressure Liquid before the Freon Arrives at the Evaporator (Located in the Cab of a Tractor) where the next heat Exchange Process begins. The Evaporator is where the air conditioner picks up the heat from inside the cab. The Evaporator also removes the Humidity from the Cab Air as water collects on the coils and drains through the drop pan and drain tubes. When the Cab Blower blows air over the Cold Coils of the Evaporator the heat from inside the cab gets absorbed. Remember Heat moves to Cooler surfaces is one of the Laws of Heat Transfer. The Fan helps facilitate this heat transfer. As the Freon absorbs heat from the cab it starts to evaporate into a gas. Creating the Low Pressure Gas that returns to the Low Side of the Expansion Valve where it regulates flow to the compressor. And the cycle starts all over again.
In Short Term: Freon Takes the Heat Out of the Cab and Transfers it to the Condenser to Cool the Cab and the Cycle Happens all Day Long.
But what causes Air Conditioning to Fail or Not Cool as Designed???
1) Restriction in Condenser:
If the Condenser fins get blocked by dirt, debris, slimed with oil or other materials that prevent air flow across the coils it reduces or prevents Heat Transfer from the Condenser to the Outside Air. For Example if it is 100° inside the cab and normally we mentioned Air Conditioning can remove 15° to 25° of heat from the cab. So we say on average 20° is the heat removed by the Freon but the condenser is restricted and can only transfer 15° because of restriction. The Longer it runs the less and less the heat it can remove from the air because the difference in Freon to Cab Air Temperature becomes the same. Then the condenser gets hotter and hotter and restrictions cause the system to creates High Freon Pressures and shuts down or the cab temperature is too hot or same as outside air.
First Step we Recommend is Blowing Out the Condenser with Compressed Air Opposite the Direction of Air Flow. Blowing the same direction only makes the Material get stuck harder and deeper in the fins of the Condenser. Water is the last resort and should be used in the direction...Opposite the Direction of Air Flow. If you use water then you need to use Air after to make sure to remove any lodged material. Water actually causes the material to expand and makes it harder to remove. Air is your best friend and a Tool Like the AGCO Parts Air Comb works Great to Blow Material in the tight spaces of the Condenser Location.
2) Restriction in Evaporator:
The same restriction effects can happen at the Evaporator where it reduces the air flow from the cab blower that blows air through the coils so the Freon can absorb the heat from inside the cab. Plus it also restricts the blowing of air inside the cab as the removal of heat creates a cooling feel in the cab. If the Air Flow is restricted the cab will heat up as it limits the ability of the system to remove heat. This may be more than than many customers would desire to tackle as it requires more extensive work to get access in the cab. Often the cab roof must be removed to access the Evaporator. Cleaning is not as simple with air as you can blow dirt into the ventilation system into the cab. Since Evaporators also remove the Humidity water can attract the dirt and cause stubborn cleaning. There are Evaporator or Coil Cleaning Products that are mild acids that break up the material and then low volume/low pressure washing with water the material down the drain pan and drain tube can clean the area. Air is recommended for mild conditions but cover vents to keep from inducing dirt into the cab. See Cab Filters for More Information on Keeping Evaporator Clean.
3) Cab Air Filters Restriction:
Tractor Cabs filter the incoming air into the Air box that the Evaporator is located (as Pictured Above) to reduce dirt and debris from entering the Evaporator. Either from the Outside Air or Recirculated Cab Air. If Filters get restricted it will reduce the air that can travel through the Evaporator and reduce the efficiency of the Air Conditioning System. Similar to Plugged Engine Air Filters or a Human Trying to breathe through a handkerchief or mask. All Cabs have External Air Filter that Filters incoming Air. In Dusty or Dry Conditions this filter may need to be cleaned daily or filter replaced on more frequent basis to allow proper air flow.
Examples of External Cab Air Filters:
Example of Internal Cab Air Filter:
4) Air Recirculation: Cab Tractors have ways to Circulate Inside Air or Bring in Eternal Fresh Air or Mix of Both. When Outside temperatures are high it is important to reduce adding hot outside air as it is harder to remove the heat. Recirculating inside Cab air is easier to get the Maximum Heat out of the Air. Remember Air Conditioning can remove approximately 20°F of heat from the Air. Different Tractors have different ways they recirculate air. We will add some pictures of different series of current Massey Ferguson Tractors Air Recirculation Systems.
Massey Ferguson 1800M/2800M Compact Tractors: Use an adjustable valve to Mix inside (Recirculated) and outside (Fresh) Air.
Massey Ferguson Global Series Tractor (4700, 5700 & 6700 Series): use a Recirculating Vent, similar to your homes return vent that allows Cab Air to Recirculate through the Evaporator to be cooled again.
Massey Ferguson S Series Tractors: use a Recirculating Valve to determine how much inside air is recirculated versus external fresh air is introduced into the cab.
5) Loss of Freon: If your tractor has a leak in the system it can have a very slow leak and allow some of the Freon to escape. If your System is not at Recommended Freon Capacity it limits how much heat can be removed and heat exchanged...resulting in loss of efficiency....so instead of 20° of heat removal we start dropping to 19°, then 18°, then 17° and so on until the Low Freon Switch Cuts the System Off.
TIP: Freon has Air Condition Oil that lubricates Hoses and Orings as it circulates. During the Air Conditioner "Off Season" here in the Midwest that is winter, the Freon is not circulated because you don't use AC in the Winter. But we do get some warm days that are enough to get the Air Conditioner to Cycle on or if you have a warm shed....Turn the Air Conditioner on so it can circulate the oil to keep hoses and orings lubricated and prevent them from drying out. Automobiles do this with the Defrost Cycle. Later Model Systems are less prone than older models but still a good tip to help extend the life and reduce maintenance costs of adding ore Freon.
6) Heater Valve Still On:
Many Tractors have Manual Heater Valve on the Engine or Coolant Hoses that supply Coolant to the Heater Core that heats the Cab. These Valves positively turns off the flow of warm coolant through the can in the summertime. Your Thermostat valve is a mechanical shutoff but is a butterfly style valve and warm water can still trickle or flow through the cab and is located behind the evaporator so you start warming cool air and reducing cooling efficiency or negates it. Shut off the valve once it warms in the spring or early summer and turn if back on in the fall or early winter. We did a Video on Several Models where the location is:
Understanding How Air Conditioning Works will help you understand the Importance and How to Maximize Cooling.
First lets start with the Law of Heat Transfer, Heat always moves to a cooler surface. Fire up your stove and Put a Pan of Water on the Stove. The Heat from the Flame or Electric Element transfer to the pan first because it is cooler. Then add water and the Pan transfer heat to the water and after a while it begins to boil. Next insert a metal spoon into the water and the heat transfers from the water to the spoon. Then when you grab the metal spoon your hand is colder and it burns your hand. Heat always transfers to colder surface. The same happens in an Air Conditioning System or Cooling System.
Now lets talk Air Conditioning...and it doesn't matter Tractors, Home, Truck, Car....all systems use the same Basics & Principals of Air Conditioning
#1 Air Conditioning Does NOT Cool it Removes Heat!
#2 Air Conditioning Cooling is limited by Outside Temperature (Air Conditioning can remove approximately 15° to 25°F from Outside Temperature)
So How does Air Conditioning Work if it doesn't Cool...
In the Above Picture you can see the Basic Components of an Air Conditioning System. The Compressor takes Low Pressure/High Heat Freon Gas and Compresses it into High Pressure/High Heat Gas that enters the Condenser that is normally located in front of the Radiator. Since air is blowing through the condenser from the engine fan or auxiliary condenser fan the condenser is a cooler surface than the Freon Gas Temperature and Heat Exchange happens as the condenser fins absorb the heat from the Freon Gas. The Air from Fan pulls air that is cooler and removes the heat from the condenser, thus cooling the Freon too. During this process of Heat Exchange in the condenser the Freon changes from a High Pressure gas to High Pressure Liquid. After it leaves the Condenser it typically enters as Receiver/Dryer as a High Pressure Liquid. The Receiver/Dryer acts as Storage Tank and Also Removes Moisture from the Freon. Once it travels from the Receiver/Drier the High Pressure/Liquid Freon moved into one side of the Expansion Valve that converts the High Pressure/Liquid to Low Pressure Liquid before the Freon Arrives at the Evaporator (Located in the Cab of a Tractor) where the next heat Exchange Process begins. The Evaporator is where the air conditioner picks up the heat from inside the cab. The Evaporator also removes the Humidity from the Cab Air as water collects on the coils and drains through the drop pan and drain tubes. When the Cab Blower blows air over the Cold Coils of the Evaporator the heat from inside the cab gets absorbed. Remember Heat moves to Cooler surfaces is one of the Laws of Heat Transfer. The Fan helps facilitate this heat transfer. As the Freon absorbs heat from the cab it starts to evaporate into a gas. Creating the Low Pressure Gas that returns to the Low Side of the Expansion Valve where it regulates flow to the compressor. And the cycle starts all over again.
In Short Term: Freon Takes the Heat Out of the Cab and Transfers it to the Condenser to Cool the Cab and the Cycle Happens all Day Long.
But what causes Air Conditioning to Fail or Not Cool as Designed???
1) Restriction in Condenser:
If the Condenser fins get blocked by dirt, debris, slimed with oil or other materials that prevent air flow across the coils it reduces or prevents Heat Transfer from the Condenser to the Outside Air. For Example if it is 100° inside the cab and normally we mentioned Air Conditioning can remove 15° to 25° of heat from the cab. So we say on average 20° is the heat removed by the Freon but the condenser is restricted and can only transfer 15° because of restriction. The Longer it runs the less and less the heat it can remove from the air because the difference in Freon to Cab Air Temperature becomes the same. Then the condenser gets hotter and hotter and restrictions cause the system to creates High Freon Pressures and shuts down or the cab temperature is too hot or same as outside air.
First Step we Recommend is Blowing Out the Condenser with Compressed Air Opposite the Direction of Air Flow. Blowing the same direction only makes the Material get stuck harder and deeper in the fins of the Condenser. Water is the last resort and should be used in the direction...Opposite the Direction of Air Flow. If you use water then you need to use Air after to make sure to remove any lodged material. Water actually causes the material to expand and makes it harder to remove. Air is your best friend and a Tool Like the AGCO Parts Air Comb works Great to Blow Material in the tight spaces of the Condenser Location.
2) Restriction in Evaporator:
The same restriction effects can happen at the Evaporator where it reduces the air flow from the cab blower that blows air through the coils so the Freon can absorb the heat from inside the cab. Plus it also restricts the blowing of air inside the cab as the removal of heat creates a cooling feel in the cab. If the Air Flow is restricted the cab will heat up as it limits the ability of the system to remove heat. This may be more than than many customers would desire to tackle as it requires more extensive work to get access in the cab. Often the cab roof must be removed to access the Evaporator. Cleaning is not as simple with air as you can blow dirt into the ventilation system into the cab. Since Evaporators also remove the Humidity water can attract the dirt and cause stubborn cleaning. There are Evaporator or Coil Cleaning Products that are mild acids that break up the material and then low volume/low pressure washing with water the material down the drain pan and drain tube can clean the area. Air is recommended for mild conditions but cover vents to keep from inducing dirt into the cab. See Cab Filters for More Information on Keeping Evaporator Clean.
3) Cab Air Filters Restriction:
Tractor Cabs filter the incoming air into the Air box that the Evaporator is located (as Pictured Above) to reduce dirt and debris from entering the Evaporator. Either from the Outside Air or Recirculated Cab Air. If Filters get restricted it will reduce the air that can travel through the Evaporator and reduce the efficiency of the Air Conditioning System. Similar to Plugged Engine Air Filters or a Human Trying to breathe through a handkerchief or mask. All Cabs have External Air Filter that Filters incoming Air. In Dusty or Dry Conditions this filter may need to be cleaned daily or filter replaced on more frequent basis to allow proper air flow.
Examples of External Cab Air Filters:
Example of Internal Cab Air Filter:
4) Air Recirculation: Cab Tractors have ways to Circulate Inside Air or Bring in Eternal Fresh Air or Mix of Both. When Outside temperatures are high it is important to reduce adding hot outside air as it is harder to remove the heat. Recirculating inside Cab air is easier to get the Maximum Heat out of the Air. Remember Air Conditioning can remove approximately 20°F of heat from the Air. Different Tractors have different ways they recirculate air. We will add some pictures of different series of current Massey Ferguson Tractors Air Recirculation Systems.
Massey Ferguson 1800M/2800M Compact Tractors: Use an adjustable valve to Mix inside (Recirculated) and outside (Fresh) Air.
Massey Ferguson Global Series Tractor (4700, 5700 & 6700 Series): use a Recirculating Vent, similar to your homes return vent that allows Cab Air to Recirculate through the Evaporator to be cooled again.
Massey Ferguson S Series Tractors: use a Recirculating Valve to determine how much inside air is recirculated versus external fresh air is introduced into the cab.
5) Loss of Freon: If your tractor has a leak in the system it can have a very slow leak and allow some of the Freon to escape. If your System is not at Recommended Freon Capacity it limits how much heat can be removed and heat exchanged...resulting in loss of efficiency....so instead of 20° of heat removal we start dropping to 19°, then 18°, then 17° and so on until the Low Freon Switch Cuts the System Off.
TIP: Freon has Air Condition Oil that lubricates Hoses and Orings as it circulates. During the Air Conditioner "Off Season" here in the Midwest that is winter, the Freon is not circulated because you don't use AC in the Winter. But we do get some warm days that are enough to get the Air Conditioner to Cycle on or if you have a warm shed....Turn the Air Conditioner on so it can circulate the oil to keep hoses and orings lubricated and prevent them from drying out. Automobiles do this with the Defrost Cycle. Later Model Systems are less prone than older models but still a good tip to help extend the life and reduce maintenance costs of adding ore Freon.
6) Heater Valve Still On:
Many Tractors have Manual Heater Valve on the Engine or Coolant Hoses that supply Coolant to the Heater Core that heats the Cab. These Valves positively turns off the flow of warm coolant through the can in the summertime. Your Thermostat valve is a mechanical shutoff but is a butterfly style valve and warm water can still trickle or flow through the cab and is located behind the evaporator so you start warming cool air and reducing cooling efficiency or negates it. Shut off the valve once it warms in the spring or early summer and turn if back on in the fall or early winter. We did a Video on Several Models where the location is: