A/C Charge by Myself

[RustyRatRod]

I am not getting into the argument but I charged my first AC system in probably 1979. Been to MANY different classes with GM, Ford, Chrysler and Toyota. In AUTOMOTIVE AC systems, I was trained...and everybody I know to charge from the low side. That's how I've always done it. That's how everybody around here does it. Never had an issue.

Auto Air of Macon has been in business better than fifty years. That's how they do it. That's how they train people in their classes to do it.

Again, I am not arguing. Just stating that's how everybody around here has always done it. I have even had home HVAC guys tell me it's backwards from their work, that they DO charge through the high side. I have also seen compressor failures BECAUSE of being charged through the high side. EVERY SINGLE AC kit you see in the auto parts store that comes with a charging hose comes with a hose that fits the low side only. The instructions on every single kit we sell say to charge through the low side. I even have a set of nice Robinair gauges that read on the low side gauge "CHARGE THROUGH LOW SIDE".

Is it perhaps a difference between automotive and other types of HVAC and refrigeration?

 

[toolmanmike]

I am not getting into the argument but I charged my first AC system in probably 1979. Been to MANY different classes with GM, Ford, Chrysler and Toyota. In AUTOMOTIVE AC systems, I was trained...and everybody I know to charge from the low side. That's how I've always done it. That's how everybody around here does it. Never had an issue.

Auto Air of Macon has been in business better than fifty years. That's how they do it. That's how they train people in their classes to do it.

Again, I am not arguing. Just stating that's how everybody around here has always done it. I have even had home HVAC guys tell me it's backwards from their work, that they DO charge through the high side. I have also seen compressor failures BECAUSE of being charged through the high side. EVERY SINGLE AC kit you see in the auto parts store that comes with a charging hose comes with a hose that fits the low side only. The instructions on every single kit we sell say to charge through the low side. I even have a set of nice Robinair gauges that read on the low side gauge "CHARGE THROUGH LOW SIDE".

Is it perhaps a difference between automotive and other types of HVAC and refrigeration?

Agreed!

 

[67Dart273]

Is it perhaps a difference between automotive and other types of HVAC and refrigeration?

No. No difference. The ONLY reason they teach low side only is because some of these folks don't have that much experience, and no one wants to "chance" a liquid slug into a compressor.

The ONLY THING you are doing, here, on the high side IS WITH THE SYSTEM STOPPED. You are doing what amounts to the "same thing" that the condenser is doing, IE sending "high pressure" liquid from the high side to the low side.

As long as you don't "dump" any liquid into the low side, there is zero chance of ever hurting a compressor.

I'm not saying you HAVE to do this. I'm saying that claiming it is damaging is wrong. When you get into larger systems, and it matters not whether they are high, med, or low temp systems, you get something that holds 5 lb or more of gas, you will be there all week long trying to charge it with gas on the low side.

This in my mind, is just one more example of "skeered liability" gone amuck. One of my favorites is I used to have a plastic case of KD tool cold chisels. The federal warning said "do not strike with hard metallic object." I guess a ball pein hammer is out of the question!!

 

[RustyRatRod]

That makes sense. Thanks. And yes, I read the very FIRST time and UNDERSTOOD when you said with the system OFF.

LOL

Let me ask you this. Is there an advantage in doing it one way as opposed to the other? In other words will one way have a better outcome and possibly make it cool better?

 

[67Dart273]

Furthermore, some modern blends like 410A MUST BE charged as a liquid to avoid separation, see here:

How to properly charge an air conditioning system

"Blends like R410a or 404a must be added to a system as a liquid. Pure refrigerants like R22 can be added in liquid or vapor states. If adding liquid into the suction like, throttle it in slowly to avoid slugging the compressor or diluting and washing out the compressor oil."

Heed this: "adding liquid into suction, throttle" What they are talking about is inverting the can for liquid, and liquid right up to the gauge manifold, but working the valve to adjust flow and pressure to avoid liquid into the compressor.

 

[67Dart273]

That makes sense. Thanks. And yes, I read the very FIRST time and UNDERSTOOD when you said with the system OFF.

LOL

Let me ask you this. Is there an advantage in doing it one way as opposed to the other? In other words will one way have a better outcome and possibly make it cool better?

In most cases simply a time saver, but if you are adding one of these mixed oil/ refrigerant cans, liquid could very well help separation, as in the 410A example above. in AC systems, one thing you DO NOT want to do on a hermetic compressor, is to run the thing with the internals in a vacuum. This can cause electrical problems, corona / flash over, etc, as well as quickly building heat in the compressor, which is cooled by returning refrigerant to the "can" of the compressor.

 

[RustyRatRod]

Muchas grassy ***, Del!

 

[toolmanmike]

In most cases simply a time saver, but if you are adding one of these mixed oil/ refrigerant cans, liquid could very well help separation, as in the 410A example above. in AC systems, one thing you DO NOT want to do on a hermetic compressor, is to run the thing with the internals in a vacuum. This can cause electrical problems, corona / flash over, etc, as well as quickly building heat in the compressor, which is cooled by returning refrigerant to the "can" of the compressor.

Just to keep us on task here, let's not talk about 410A. It's a freon for residential ac units.

 

[toolmanmike]

There has been a very good discussion here. I have learned a lot. The bottom line is the original poster should get some help charging his AC.

 

[slantsixdan]

Let me ask you this. Is there an advantage in doing it one way as opposed to the other? In other words will one way have a better outcome and possibly make it cool better?

No. Optimal outcome is a result of proper system assembly, prep, and charging. Taking a sloppy "Yer pressures should be somewhere in the neighborhood, whatever, it's all good, not rocket science, hurr" approach works about as well as 'Plug gap? Don't matter, as long as it's somewheres between 0.020" and 0.060" yer fine, it's not rocket science' or 'Fuel mixture? Pfft, whatever. Just install whatever jets you happen to find in the bottom of your toolbox and turn the idle mixture screw till the engine stays running, it's not rocket science'. If the job's worth doing, it's worth doing properly.

A/C systems (mobile or not) can be charged via the low side or via the high side. High-side charging can be faster. The procedures are different, and (again) you have to really know what you're doing or you will break stuff and/or hurt yourself. The risks, dangers and consequences of high-side charging when you don't know what you're doing are greater than those of low-side charging.

 

[rednesss]

I am not getting into the argument but I charged my first AC system in probably 1979. Been to MANY different classes with GM, Ford, Chrysler and Toyota. In AUTOMOTIVE AC systems, I was trained...and everybody I know to charge from the low side. That's how I've always done it. That's how everybody around here does it. Never had an issue.

Auto Air of Macon has been in business better than fifty years. That's how they do it. That's how they train people in their classes to do it.

Again, I am not arguing. Just stating that's how everybody around here has always done it. I have even had home HVAC guys tell me it's backwards from their work, that they DO charge through the high side. I have also seen compressor failures BECAUSE of being charged through the high side. EVERY SINGLE AC kit you see in the auto parts store that comes with a charging hose comes with a hose that fits the low side only. The instructions on every single kit we sell say to charge through the low side. I even have a set of nice Robinair gauges that read on the low side gauge "CHARGE THROUGH LOW SIDE".

Is it perhaps a difference between automotive and other types of HVAC and refrigeration?

THIS^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ but by all means, 99.9% of the planet can't be right.

 

[fastcuda68]

I have a 68 barracuda with the new sanders pump and the original a/c in the car. I just filled it with the new 134 with one of those blue hoses that hook on the low side and have a little gauge I got from wal mart. I didnt use a vaccum at all, I did use a new drier. It's been working great for 4 years now, ymmv.