How-To: Air Conditioning Advice.

[ken1mod]

Gentlemen,

 

By trade I am an air conditioning engineer and i have some good advice for the people on this forum.

 

Many of us check the temperatures of our a/c units once in a while. I love my IR thermometer where you just point the device at the a/c outlet and read the temp. Great fun.\\We also may notice that the temp is not as cold now as it was in early june before the humidity went up.

 

This is NORMAL. Humidity is the same as heat to your a/c. I would see 40 degree air in june and now the temp is in the 50s.

 

Pressures? Who cares. As long as the unit is cooling and the accumulator is cold to the touch, it is working properly and charged correctly. Adding more refrigerant at this point will cause the unit to run constantly (not cycle as it is supposed to) and put out warmer air. Pressures can be important to diagnose major problems but this is rare.

 

A dirty leaf covered condenser will cause high high side pressures but you can look at the darn thing and see that it is dirty. I don't think I have ever hooked up the high side gauge unless I was trying to impress my wife. Refrigeration happens in the low side of the system. If the unit is cooling the car and the accumulator cold, it is properly charged. You actually do not need gauges to properly charge a healthy system that is just a bit low on refrigerant.

 

A properly charged system will cycle on the accumulator pressure switch every minute or so. It does this to keep from chilling the evaporator below 32 degrees which would freeze it into a chunk of ice blocking airflow.

 

So, if your unit is not cooling the vehicle well and you think it may be low on refrigerant, start the engine, have someone hold about 1200 rpm with the blower on high. Open the hood and give things a couple of minutes to stabilize.

 

Put your hand on the accumulator. If it is not cold, add maybe a half can of refrigerant slowly. The unit is perfectly charged when the accumulator is cold and the unit cycles about every minute or so. The cycle time varies with conditions but it should cycle. If it does not cycle ever, even at a lower blower speed, the unit is probably overcharged. These units are not charge critical and will work great plus or minus a half pound or so of the correct amount and they all leak slightly from hoses and particularly the shaft seal of the compressor. This is why they are designed to not be charge critical.

 

I hope this info is useful to anyone having problems.

 

Ken

[jblakeney]

My rule of thumb has always been..... If it sweats, at the dryer, don't mess with it unless it is making noise... Some coil cleaner on the condenser is one thing I do from time to time....... It helps to keep it clean from trash....

 

What kind of A/C stuff do you do Ken??

 

Jbo

[ken1mod]

My rule of thumb has always been..... If it sweats, at the dryer, don't mess with it unless it is making noise... Some coil cleaner on the condenser is one thing I do from time to time....... It helps to keep it clean from trash....

 

What kind of A/C stuff do you do Ken??

 

Jbo

 

A/c has always fascinated me even as a kid. I am currently engaged in heat reclaim from air conditioning units. Powerful stuff. Check out www.coolpoolheat.com. One can heat oodles of domestic hot water or swimming pools. Far better than solar for both these processes. A 5 ton a/c on your home throws away the heat equivalent of 1 gallon of gasoline for each hour it runs.

 

Ken

[ken1mod]

sweating accumulator=healthy system.

[MaverickZ71]

Good stuff. For those of us who may not be familiar with all of the parts, could you give us a quick idea where to find the accumulator, receiver, and drier? I do know where the compressor is. Thanks!

[ken1mod]

Gentlemen,

 

The accumulator is the aluminum container that is mounted on the passenger side firewall in the engine compartment. It accepts liquid spill over from the evaporator and holds a bit of liquid in normal operation. It has two pipe connections one goes into the passenger compartment (from the evaporator) and the other goes to the suction intake of the compressor. This is also where the cycling compressor switch is mounted and it also has the low side pressure service port. This is where you add refrigerant if needed.

 

Technically, our systems do not use a "receiver" this is a high side container at the outlet of the condenser and was mounted in front of the radiator/condenser. They used to have a sight glass back when the a/c used an expansion valve )txv). The accumulator does "receive" spillover liquid from the evaporator and serves a similar purpose but it is in the low side of the system. That of holding excess refrigerant where it wont hurt anything.

 

By the way, cold pipes = low side, hot pipes = high side.

 

Jblakeny said it right earlier, if the accumulator is sweating, close the hood, your a/c is doing its best. Go inside and have a beer.

 

Ken

[[email protected]]

Ken--I worked for Automated Logic, a controls company for HVAC equipment, and had the opportunity to work in Florida last year for a few weeks, working on their "heat pumps", which is basically an air conditioner that is reversed, so it blows the warm air into the building, and the cold air out into the environment. Being from Wisconsin, we have never had the opportunity to work on/ see one of those before, so it was pretty interesting.

[jblakeney]

Ken--I worked for Automated Logic, a controls company for HVAC equipment, and had the opportunity to work in Florida last year for a few weeks, working on their "heat pumps", which is basically an air conditioner that is reversed, so it blows the warm air into the building, and the cold air out into the environment. Being from Wisconsin, we have never had the opportunity to work on/ see one of those before, so it was pretty interesting.

 

HAHAHA, ya..... I am just curious... What do you use in extreme cold climates... for heat that is.... I am in south Mississippi.... Heat pumps are second nature..... Strips are optional... Cold out side you radiate heat and chill inside.... When you flip the change over valve, you strike that and reverse it...

 

Jbo

[truckofwinandawesome]

Gentlemen,

 

The accumulator is the aluminum container that is mounted on the passenger side firewall in the engine compartment. It accepts liquid spill over from the evaporator and holds a bit of liquid in normal operation. It has two pipe connections one goes into the passenger compartment (from the evaporator) and the other goes to the suction intake of the compressor. This is also where the cycling compressor switch is mounted and it also has the low side pressure service port. This is where you add refrigerant if needed.

 

Technically, our systems do not use a "receiver" this is a high side container at the outlet of the condenser and was mounted in front of the radiator/condenser. They used to have a sight glass back when the a/c used an expansion valve )txv). The accumulator does "receive" spillover liquid from the evaporator and serves a similar purpose but it is in the low side of the system. That of holding excess refrigerant where it wont hurt anything.

 

By the way, cold pipes = low side, hot pipes = high side.

 

Jblakeny said it right earlier, if the accumulator is sweating, close the hood, your a/c is doing its best. Go inside and have a beer.

 

Ken

 

the Accumulator also has a small container of Dessicant to suck up any moisture in the system.

[[email protected]]

Gentlemen,

 

The accumulator is the aluminum container that is mounted on the passenger side firewall in the engine compartment. It accepts liquid spill over from the evaporator and holds a bit of liquid in normal operation. It has two pipe connections one goes into the passenger compartment (from the evaporator) and the other goes to the suction intake of the compressor. This is also where the cycling compressor switch is mounted and it also has the low side pressure service port. This is where you add refrigerant if needed.

 

Technically, our systems do not use a "receiver" this is a high side container at the outlet of the condenser and was mounted in front of the radiator/condenser. They used to have a sight glass back when the a/c used an expansion valve )txv). The accumulator does "receive" spillover liquid from the evaporator and serves a similar purpose but it is in the low side of the system. That of holding excess refrigerant where it wont hurt anything.

 

By the way, cold pipes = low side, hot pipes = high side.

 

Jblakeny said it right earlier, if the accumulator is sweating, close the hood, your a/c is doing its best. Go inside and have a beer.

 

Ken

 

the Accumulator also has a small container of Dessicant to suck up any moisture in the system.

 

 

Sounds like another normal maintenance item to me, how does one go about changing this dessicant. Seems like after time, it would get water logged and no longer useful. 

[jblakeney]

Gentlemen,

 

The accumulator is the aluminum container that is mounted on the passenger side firewall in the engine compartment. It accepts liquid spill over from the evaporator and holds a bit of liquid in normal operation. It has two pipe connections one goes into the passenger compartment (from the evaporator) and the other goes to the suction intake of the compressor. This is also where the cycling compressor switch is mounted and it also has the low side pressure service port. This is where you add refrigerant if needed.

 

Technically, our systems do not use a "receiver" this is a high side container at the outlet of the condenser and was mounted in front of the radiator/condenser. They used to have a sight glass back when the a/c used an expansion valve )txv). The accumulator does "receive" spillover liquid from the evaporator and serves a similar purpose but it is in the low side of the system. That of holding excess refrigerant where it wont hurt anything.

 

By the way, cold pipes = low side, hot pipes = high side.

 

Jblakeny said it right earlier, if the accumulator is sweating, close the hood, your a/c is doing its best. Go inside and have a beer.

 

Ken

 

the Accumulator also has a small container of Dessicant to suck up any moisture in the system.

 

 

Sounds like another normal maintenance item to me, how does one go about changing this dessicant. Seems like after time, it would get water logged and no longer useful. 

 

 

Maintenance is preformed on the accumulator when the system is opened for service. i.e. when the lines are broken open, such as A/C job. Compressor, Accumulator, Orifice and/or expansion block,........

 

A running system with no problems that has not been opened before no need to be worried about this.....

 

But to answer your question you have to change the accumulator. Which will require you to vacuum the system. And recharge the system... NOT NORMAL MAINTENANCE.

 

Jbo

[truckofwinandawesome]

Gentlemen,

 

The accumulator is the aluminum container that is mounted on the passenger side firewall in the engine compartment. It accepts liquid spill over from the evaporator and holds a bit of liquid in normal operation. It has two pipe connections one goes into the passenger compartment (from the evaporator) and the other goes to the suction intake of the compressor. This is also where the cycling compressor switch is mounted and it also has the low side pressure service port. This is where you add refrigerant if needed.

 

Technically, our systems do not use a "receiver" this is a high side container at the outlet of the condenser and was mounted in front of the radiator/condenser. They used to have a sight glass back when the a/c used an expansion valve )txv). The accumulator does "receive" spillover liquid from the evaporator and serves a similar purpose but it is in the low side of the system. That of holding excess refrigerant where it wont hurt anything.

 

By the way, cold pipes = low side, hot pipes = high side.

 

Jblakeny said it right earlier, if the accumulator is sweating, close the hood, your a/c is doing its best. Go inside and have a beer.

 

Ken

 

the Accumulator also has a small container of Dessicant to suck up any moisture in the system.

 

 

Sounds like another normal maintenance item to me, how does one go about changing this dessicant. Seems like after time, it would get water logged and no longer useful.

 

 

Maintenance is preformed on the accumulator when the system is opened for service. i.e. when the lines are broken open, such as A/C job. Compressor, Accumulator, Orifice and/or expansion block,........

 

A running system with no problems that has not been opened before no need to be worried about this.....

 

But to answer your question you have to change the accumulator. Which will require you to vacuum the system. And recharge the system... NOT NORMAL MAINTENANCE.

 

Jbo

 

 

you beat me to the punch, the Dessicant in the Accumulator is NOT USER SERVICABLE, because as soon as you open the system, the dessicant is ruined because of the Moisture laden air, and because the Accumulator is a Sealed unit apart from the A/C lines.

[dewfpo]

you beat me to the punch, the Dessicant in the Accumulator is NOT USER SERVICABLE, because as soon as you open the system, the dessicant is ruined because of the Moisture laden air, and because the Accumulator is a Sealed unit apart from the A/C lines.

 

I must disagree with the above statement. Just opening the system does not necessarily ruin the dessicant. Maybe in high humidity areas and/or if the system has been open for a while, but a brief opening to change out something like an orifice valve in a very dry climate does not necessarily require the accumulator to be replaced.

 

DEWFPO

[jblakeney]

you beat me to the punch, the Dessicant in the Accumulator is NOT USER SERVICABLE, because as soon as you open the system, the dessicant is ruined because of the Moisture laden air, and because the Accumulator is a Sealed unit apart from the A/C lines.

 

I must disagree with the above statement. Just opening the system does not necessarily ruin the dessicant. Maybe in high humidity areas and/or if the system has been open for a while, but a brief opening to change out something like an orifice valve in a very dry climate does not necessarily require the accumulator to be replaced.

 

DEWFPO

 

 

Providing you vacuum everything out in my area...... And the system was not left open for a long time.... Maybe... Would I, NO. I would replace it and vacuum the system. I don't like come backs.

 

Jbo

[Lahey99]

Great info above..i too am a refrigeration mechanic and there is no need to go above and beyond what the orignal post has stated. A++