Explain to me why too little refrigerant is a bad thing?

[fleabag]

I remember reading somewhere that if the A/C in a car or anywhere really cools "too much" that it could have too little refrigerant in there. I understand that if it's really cold on one side then it should be really hot on the other side but couldn't you then just run the compressor motor slower so that ice doesn't form on the cool side and on the hot side it doesn't get too hot? Lets say to get decent cooling in a properly pressurized system the electric motor has to run at 250rpm. Now let's say some refrigerant escapes and it now runs so cold that ice forms on one side. But then you take down the RPM of the electric motor from 250rpm to 200rpm, so now the coils are cold enough and not too cold. Why can't you just continue with this setup? Why would there be a specified pressure if the system can run at a lower pressure and at a lower speed while providing the same cooling effect?

I really have limited knowledge on refrigerants so if anyone can enlighten me, please do.

 

[Crusty]

Posting in a fleabag thread!

 

[coxmaster]

Shouldnt this be in the garage?

 

[PottedMeat]

Shouldnt this be in the garage?

yes. this would be better answered in THE GARAGE.

 

[deadlyapp]

I could give you a response based on the thermodynamic properties of an AC system, but I really don't want to think or aid you in any way.

 

[sdifox]

Shouldnt this be in the garage?

He got his ass banned from The Garage.

 

[PhoKingGuy]

The AC in my cobalt was undercharged from the factory (haaaaa), it didnt cool better. It just didn't work period.

 

[BoomerD]

Why should anyone even attempt to answer a Fleadip question since he already knows everything and will only tell the poster how he's wrong...

 

[coxmaster]

He got his ass banned from The Garage.

I know.. I just wanted to ask

 

[fleabag]

He got his ass banned from The Garage.

Well it's not really related to "garage" stuff considering that it's about the general principles of thermodynamic cycles and air conditioners. Air conditioners come in other things besides vehicles.

 

[Capt Caveman]

I really have limited knowledge on refrigerants so if anyone can enlighten me, please do.

Excuse me, but you have limited knowledge on just about everything.

 

[fleabag]

Why should anyone even attempt to answer a Fleadip question since he already knows everything and will only tell the poster how he's wrong...

Because of this:

I really have limited knowledge on refrigerants so if anyone can enlighten me, please do.

I mean I can argue about it to some extent, it just depends on people's answer to this question. Sometimes you guys make smart assed comments that have no bearing on reality, or are very broad generalized statements that can't be backed up.

 

[moshquerade]

Because of this:



I mean I can argue about it to some extent, it just depends on people's answer to this question. Sometimes you guys make smart assed comments that have no bearing on reality, or are very broad generalized statements that can't be backed up.

Even when we make a specific statement that can be backed up you won't grasp it.

 

[fleabag]

Excuse me, but you have limited knowledge on just about everything.

Wrong. I'm an expert when it comes to tire inflation which is what got me the job at the gas station around the corner. They specifically mentioned in the newspaper listing "looking for expert at tire inflation and all things related to fuel economy and those who know more than some Korean engineers at Hyundai/Kia"...so I responded and got the job.

 

[grrl]

Posting in a fleatard thread.

I could give you a response based on the thermodynamic properties of an AC system, but I really don't want to think or aid you in any way.

This. Your past behavior has nullified your right to appropriate responses to your questions.

Why should anyone even attempt to answer a Fleadip question since he already knows everything and will only tell the poster how he's wrong...

And this. (See above.)

However, I'll give you one hint as to why your brainfart doesn't work - volumetric efficiency.


EDIT: And because of this attitude:

I mean I can argue about it to some extent, it just depends on people's answer to this question. Sometimes you guys make smart assed comments that have no bearing on reality, or are very broad generalized statements that can't be backed up.

Why would you "argue" about something you say you know nothing about?

And this demonstration of your cognitive deficiency (as well as your post immediately after this one):

Wrong. I'm an expert when it comes to tire inflation which is what got me the job at the gas station around the corner. They specifically mentioned in the newspaper listing "looking for expert at tire inflation and all things related to fuel economy and those who know more than some Korean engineers at Hyundai/Kia"...so I responded and got the job.

 

[fleabag]

Even when we make specific statements that can be backed up you won't grasp it.

A manufacturer's generic warning statement that is reprinted as a thoughtless, broad disclaimer I'm not going to believe especially when I can easily prove otherwise through my own testing and the testing of others. Most of the time manufacturers are correct in their warnings and they can indeed be proven to be useful in actual practice like the warning not to run such and such compressor for more than 10 minutes at a time to prevent overheating. Or don't smoke/make any sparks near a charging battery because the hydrogen could be ignited and explode. Or "high voltage", dangerous, etc etc. I can probably think of 100 things where the manufacturer's stern warning is valid and should be followed for every warning where it's just a load of crap and is for a limited circumstance. This whole bit about tire pressure thing is one of those, and in my experience and the experience of others has shown otherwise. What and how they come up with these warnings is perfectly logical, but that doesn't mean I have to agree with it especially if I can prove otherwise.

 

[Ika]

am I late to the party? never been in a fleabag thread before.

 

[chusteczka]

I have not been following this guy around so may be caught off guard here.

To ignore your paragraph of confusion and focus on your original question, with too little refrigerant an A/C compressor will short cycle. This means the compressor will turn on, turn off, and turn on again repeatedly in a relatively short period of time.

The compressor turns off too soon due to the low pressure switch on the inlet side when the system runs out of refrigerant. Too low of a pressure (vacuum) can weaken the seals and cause refrigerant to leak out.

The compressor then turns on again too soon because the system is asking for more refrigerant to cool off the refrigerated space.

The "short cycle" continues.


On another topic, it is good to run the A/C in the car at least once every 3 weeks or so. Even in winter (just turn the temperature dial to the hot side). This will lubricate the seals and prevent the seals from drying out. Dried out seals would allow refrigerant to leak out of the system, into the atmosphere.

It seems some of the new cars may automatically run the A/C with some of the other settings. I am not certain of this, though.

 

[killster1]

well if its leaking then its jacking up the environment ! Cant believe all you guys hate this guy so much jeez why even bother to post in this thread

 

[lxskllr]

It seems some of the new cars may automatically run the A/C with some of the other settings. I am not certain of this, though.

Defog is usually tied to the A/C system. It's an irritating practice, but I guess it ensures it gets used regularly.

 

[Pacfanweb]

^You A/C runs in the winter automatically. If you use "Defrost", or any position that directs even a little of the air to the Defrost ducts, the A/C compressor will run.

In fact, on the many of cars these days, there are only 2 positions in which the A/C does NOT run: Vent, and Floor.

The reason you can't just run the motor slower is the same reason your A/C in your car cools better if you rev it up. When the compressor runs, it pressurizes, but it also sucks....so that Latent Heat of Vaporization can take place.

It's simply not as efficient at lower speeds, even when fully charged.

There's a small "sweet spot" in which a system can be low and cause icing....if it's too low, the compressor will cycle on/off, or simply not run at all.

 

[grrl]

Defog is usually tied to the A/C system. It's an irritating practice, but I guess it ensures it gets used regularly.

That's done because it cold dry air removes the moisture more quickly.

 

[chusteczka]

Thank you for the information tying the A/C system into the Defrost/Defog setting, guys. I had not figured that out yet. :thumbsup:

 

[sdifox]

Wrong. I'm an expert when it comes to tire inflation which is what got me the job at the gas station around the corner. They specifically mentioned in the newspaper listing "looking for expert at tire inflation and all things related to fuel economy and those who know more than some Korean engineers at Hyundai/Kia"...so I responded and got the job.

Oh goodie, new sig material.

 

[lxskllr]

That's done because it cold dry air removes the moisture more quickly.

Oh, I realize that, but sometimes I don't want the A/C compressor running. Plain old A/Cless defog worked fine for decades, and it works well enough for most situations now. I like the system where you pick which set of ducts you want the air to come from, then use another selector to pick A/C or not. The biggest reason, is I like to use defog as my standard heat setting. I hate hot air on my feet, and a lot of times I don't want a breeze in my face. I like the indirect heating you get from defog.