How to choose the right compressor?

[melobyrro1]

Hi all, i need some help on how to choose the right compressor for vending machines,

 

can anyone clarify some of the specs and when it is important?

for most sodas machines probably 1/3hp is fine, but what does + mean?

is there a way to calculate the compressor ill need?

 

 

but how important is BTU? how is it gonna affect it?

 

there are compressors with less btu more hp and vice versa, whats the correlation?

[AZVendor]

Wait, wait, wait.   Why are you "choosing a compressor"?  You need to have a certified refrigeration guy doing this work.  If you think you're qualified yourself or you have to buy parts for your refrigeration guy yourself (he must not be certified) then you go by the model of compressor that is already on the deck you're rebuilding.  All of the design work was done by the vending manufacturer and all you have to do is cross reference their compressor to a new one.  Do that and you won't get the BTUs wrong, you'll get the freon lines in the correct places and, more importantly, you'll get the correct oil in the compressor. 

 

There's a lot more to this than you think, so stop thinking you can do this yourself.

[melobyrro1]

Wait, wait, wait.   Why are you "choosing a compressor"?  You need to have a certified refrigeration guy doing this work.  If you think you're qualified yourself or you have to buy parts for your refrigeration guy yourself (he must not be certified) then you go by the model of compressor that is already on the deck you're rebuilding.  All of the design work was done by the vending manufacturer and all you have to do is cross reference their compressor to a new one.  Do that and you won't get the BTUs wrong, you'll get the freon lines in the correct places and, more importantly, you'll get the correct oil in the compressor. 

 

There's a lot more to this than you think, so stop thinking you can do this yourself.

Thanks for the information, I really cant understand this groupy mentality here, "leave it for the pros" kinda of nonsense, information is information, is so undermining to say I cant do something, point me to right direction and ill learn... 

Im not asking for opinion if i should choose it or not, or if i should learn how they design ir or not, im asking how they do it, and if someone is willing they say, if not no one is obligated to respond.

 

Several months ago people here were all saying to leave decks alone, "leave for the pros" bs. 2 days with a ac tech, showed me the basics and I cant believe how easy it is to fix the vast mojority of decks, 

 

put in a service valve, change dryer, install a 3in1 starter, charge it, change the compressor, and that fixes 90% of problems ive had in the past several months.

 

boggles my minda people here were telling me to go to ac tech school, to do this stuff.

 

And to believe that people out there are doing things by the book, in this cut throat business, is so out of touch....

 

Thanks  

[rmorris1953]

I never knew it was so easy! I am surprised you needed any help. Good luck

[AngryChris]

First of all, this is a vending forum, not a refrigeration forum. If you want to learn about refrigeration, you should go to a refrigeration forum. Most of us here don't know how to repair decks because the equipment, part costs, and time cost way more than to have someone do it for us.

Secondly, there is a legal problem as most regions have laws prohibiting anyone from working on refrigeration without some kind of certificate. To advise you on something would be encouraging you to break those laws. It's just not worth it.

Every refrigeration guy I know has told me the same thing: refrigeration is generally all the same regardless of the application and no one should try to do refrigeration work without proper knowledge. You could hurt yourself or damage your refer units if you mess up.

I'm not trying to be rude, but you aren't the first guy to come here and ask for refrigeration information. It's just not worth it for most of us. It's not worth it for us to do it ourselves and it's not worth it to tell you "how to do it" when you already don't know how. If you think it's that easy, then get some refrigeration books, learn the ropes, and have at it. This just isn't the place to be asking.

Now, if you want information on how to replace electronics on most Vending machines, we can do that. Most of us don't even rebuild our own coin mechs OR validators. We send those off too.

[AZVendor]

Here's the thing about refrigeration, you have to be certified to buy parts but especially freon. There are heavily enforced federal laws that require you to know how to prevent the release of chloroflourocarbons into the atmosphere and you must pass a test to certify that you know how to prevent that release. That is the main focus of the certification and I for one believe that anyone trying to do this work without taking the proper legal steps is cheating the system and jeopardizing the environment.

This is just the beginning as just because you watched someone work on a system for 2 hours doesn't mean you understand how one works. You need to study the principals of medium temperature refrigeration to begin learning how these "simple" systems work. That study will teach you about freon types, characteristics and the nomenclature that applies to compressors. It's not necessarily responsible for us to tell anyone how to do this work without the aforementioned training.

[orsd]

Thanks for the information, I really cant understand this groupy mentality here, "leave it for the pros" kinda of nonsense, information is information, is so undermining to say I cant do something, point me to right direction and ill learn... 

Im not asking for opinion if i should choose it or not, or if i should learn how they design ir or not, im asking how they do it, and if someone is willing they say, if not no one is obligated to respond.

 

Several months ago people here were all saying to leave decks alone, "leave for the pros" bs. 2 days with a ac tech, showed me the basics and I cant believe how easy it is to fix the vast mojority of decks, 

 

put in a service valve, change dryer, install a 3in1 starter, charge it, change the compressor, and that fixes 90% of problems ive had in the past several months.

 

boggles my minda people here were telling me to go to ac tech school, to do this stuff.

 

And to believe that people out there are doing things by the book, in this cut throat business, is so out of touch....

 

Thanks  

The thing is, in the US doing the work w/o a license has the very high possibility of landing you 5 figure fines per machine, levied by a agency that absolutely, positively, DOES NOT F*CK AROUND.

That said, some of us will do stuff that does not require breaching the sealed refrigeration lines, like new 3 in 1 starters, evap fans, thermostats, etc. But actually working on stuff like compressor replacement and charging is a no go without a license, and proper equipment (vendor refrigeration systems are a different beast compared to residential HVAC and automotive HVAC systems- the 10 dollar cans of refrigerant at the auto parts store can f*ck up vendor refrigeration systems and overcharge them in a hurry.)

[melobyrro1]

Here's the thing about refrigeration, you have to be certified to buy parts but especially freon. There are heavily enforced federal laws that require you to know how to prevent the release of chloroflourocarbons into the atmosphere and you must pass a test to certify that you know how to prevent that release. That is the main focus of the certification and I for one believe that anyone trying to do this work without taking the proper legal steps is cheating the system and jeopardizing the environment.

This is just the beginning as just because you watched someone work on a system for 2 hours doesn't mean you understand how one works. You need to study the principals of medium temperature refrigeration to begin learning how these "simple" systems work. That study will teach you about freon types, characteristics and the nomenclature that applies to compressors. It's not necessarily responsible for us to tell anyone how to do this work without the aforementioned training.

not for r134, its not harmfull to environment according to epa, u can get freon, compressors, dryers at amazon, evaporators from dsvending, no license needed for r134, and i disagree that anyone need to understand all that to fix some issues, i dont need to understand how a auto engine works to change the oil, just guide thru steps how to change oil, or tires etc, at a point ure gonna hit a wall and you look for help, thats how people learn....

 

i appreciate the input, but again, it doesnt hurt to ask here, if you dont have info about it just dont respond, but i keep seeing in this forum a superiority attitude from some people, and its not welcoming...

[melobyrro1]

I never knew it was so easy! I am surprised you needed any help. Good luck

why the sarcasm? why even bother answering? if you cant add just pass on the thread...

 

for the majority of issues is more of a practice thing, getting good on welding, but like any other part in the vending machine, u dont need to understand how a light buld works to identify its bad and replace it..

 

every technical aspect eventually ure gonna hit a wall, then u raise ur knowledge, and thats healthy...

[AZVendor]

134a and all freons are covered by the federal certification requirements and buying freon from anyone other than a licensed seller who checks for certification is illegal. 

[rmorris1953]

why the sarcasm? why even bother answering? if you cant add just pass on the thread...

 

for the majority of issues is more of a practice thing, getting good on welding, but like any other part in the vending machine, u dont need to understand how a light buld works to identify its bad and replace it..

 

every technical aspect eventually ure gonna hit a wall, then u raise ur knowledge, and thats healthy...

 

 

Most of the time the people here are kind and thoughtful willing to help as much as possible. It was your sarcasm I was responding to. There are many things with refrigeration that can get you killed.

 

1. When using a torch on an R-12 system (R-12 is hazardous to the environment) when the flame comes in contact with the R-12 it is toxic and will kill you if you breathe it.

 

2. Overcharging a system can cause the compressor to overheat and has in rare cases blown out the side of the compressor causing a fire. 

 

3. Knowing what refrigerant to use is important. You can not mix because they aren't compatible. Some have to be compatible to the oil in the compressor. For the guy who is doing his job correctly gets shafted when he reclaims a system that is suppose to be R-12  and someone with no experience introduced R-134 to the system and now his reclaimed bottle is contaminated. It will cost him $100's to get it fixed.   

 

4. The system is balanced. Sometimes  there is a very fine line between overcharged and undercharged. Is it a cap tube system or an automatic expansion valve? Overcharging can cause the oil to enter the cap tube and then freeze going to the entrance to the evaporator. Undercharging can cause the evaporator to also freeze up in the vendor. 

 

5. BTU's is important in many ways but it is dependent on the system and the compressor. You have low temp, medium temp, and high temp and all are dependent upon the application.

 

6. What drier do you use? Bullet drier or a liquid drier? Do you have to change it and why? 

 

7. What is the proper gauge readings when charging the system? Do you weigh the refrigerant in? It depends on ambient temperature. Is air flowing through the evaporator or is there no air. Is the humidity high or low?  

 

8. Brazing is an art. What use to be a good seal with R-12 is no longer true with 134-A the molecules are smaller so the brazing is crucial to a good seal.  The use of a micron gauge is crucial to knowing if the system is tight. 

 

I have 30 years invested in my work and it isn't cut and dry all the time. I have been doing this long enough that I replaced the compressor that I replaced maybe 15 or more years ago. It gives me pride that I did a good job. I went to a refrigeration school after I had been doing it for 10 years. Night school two nights a week for 5 hrs. 10 months. Away from my family. I did it because it meant I could get a raise at work but I learned so much more.

 

For, me the hardest units to get right are AMS coldfoods.  Poor design IMO evaporator is too small and also the condenser is too small. It is a fine line.

 

I generally wouldn't respond but you hit a nerve with your attack. I saw it as a personal attack to me and others here that are professionals. Yes, there are cutthroats out there and rip off artist also. Most refrigeration companies don't want to deal with small units like we have. They will do them but charge a bunch. They are use to big air conditioning systems and don't want to be bothered because there isn't enough money involved. Your car mechanic doesn't know what he is doing and will blow it up.   

 

I'll end my rant here. There is a lot to know and how to do refrigeration properly and I have only barely touched what goes into it.

[melobyrro1]

Most of the time the people here are kind and thoughtful willing to help as much as possible. It was your sarcasm I was responding to. There are many things with refrigeration that can get you killed.

 

1. When using a torch on an R-12 system (R-12 is hazardous to the environment) when the flame comes in contact with the R-12 it is toxic and will kill you if you breathe it.

 

2. Overcharging a system can cause the compressor to overheat and has in rare cases blown out the side of the compressor causing a fire. 

 

3. Knowing what refrigerant to use is important. You can not mix because they aren't compatible. Some have to be compatible to the oil in the compressor. For the guy who is doing his job correctly gets shafted when he reclaims a system that is suppose to be R-12  and someone with no experience introduced R-134 to the system and now his reclaimed bottle is contaminated. It will cost him $100's to get it fixed.   

 

4. The system is balanced. Sometimes  there is a very fine line between overcharged and undercharged. Is it a cap tube system or an automatic expansion valve? Overcharging can cause the oil to enter the cap tube and then freeze going to the entrance to the evaporator. Undercharging can cause the evaporator to also freeze up in the vendor. 

 

5. BTU's is important in many ways but it is dependent on the system and the compressor. You have low temp, medium temp, and high temp and all are dependent upon the application.

 

6. What drier do you use? Bullet drier or a liquid drier? Do you have to change it and why? 

 

7. What is the proper gauge readings when charging the system? Do you weigh the refrigerant in? It depends on ambient temperature. Is air flowing through the evaporator or is there no air. Is the humidity high or low?  

 

8. Brazing is an art. What use to be a good seal with R-12 is no longer true with 134-A the molecules are smaller so the brazing is crucial to a good seal.  The use of a micron gauge is crucial to knowing if the system is tight. 

 

I have 30 years invested in my work and it isn't cut and dry all the time. I have been doing this long enough that I replaced the compressor that I replaced maybe 15 or more years ago. It gives me pride that I did a good job. I went to a refrigeration school after I had been doing it for 10 years. Night school two nights a week for 5 hrs. 10 months. Away from my family. I did it because it meant I could get a raise at work but I learned so much more.

 

For, me the hardest units to get right are AMS coldfoods.  Poor design IMO evaporator is too small and also the condenser is too small. It is a fine line.

 

I generally wouldn't respond but you hit a nerve with your attack. I saw it as a personal attack to me and others here that are professionals. Yes, there are cutthroats out there and rip off artist also. Most refrigeration companies don't want to deal with small units like we have. They will do them but charge a bunch. They are use to big air conditioning systems and don't want to be bothered because there isn't enough money involved. Your car mechanic doesn't know what he is doing and will blow it up.   

 

I'll end my rant here. There is a lot to know and how to do refrigeration properly and I have only barely touched what goes into it.

tnks, a lot of good information in ur rant, wish u had layed that out before

[melobyrro1]

tnks, a lot of good information in ur rant, wish u had layed that out before

tnks, a lot of good information in ur rant, wish u had layed that out before,

 

what i have issue with is u tell me not to touch it because of r12, i dont have any units with r12, and thats a wall prob ill never need to cross, points 1,3 n/a.

 

and there are edge problems u pointed out thats not atm applicable, 

 

there are levels of skill, mine is low, nothing wrong there, and nothing wrong with learning more with supervision.

 

the vast majority of problems i encounter is freezing at the capillary tube before getting to evaporator, or replacing the compressor, 

most of machines in my area are dn501e and r660, rvv500, bev max,

 

at my level, i only work with r134, what i do when freezing, open high line, install service valve, suck air out of it with pump, replace dryer just because its cheap and wont hurt, plug deck in, put a bit of gas in, , watch the manifold to see if loosing pressure, if not, put more freon in, feel for evaporator to be the "normal cold" stay around 25psi, this method has worked well so far for the vast mojority of problems i encounter,,,

 

brazing gets better with time and practice.

 

of course, there will be systems and walls i will hit, and at the point ill raise my level of skill.

[AngryChris]

tnks, a lot of good information in ur rant, wish u had layed that out before,

what i have issue with is u tell me not to touch it because of r12, i dont have any units with r12, and thats a wall prob ill never need to cross, points 1,3 n/a.

and there are edge problems u pointed out thats not atm applicable,

there are levels of skill, mine is low, nothing wrong there, and nothing wrong with learning more with supervision.

the vast majority of problems i encounter is freezing at the capillary tube before getting to evaporator, or replacing the compressor,

most of machines in my area are dn501e and r660, rvv500, bev max,

at my level, i only work with r134, what i do when freezing, open high line, install service valve, suck air out of it with pump, replace dryer just because its cheap and wont hurt, plug deck in, put a bit of gas in, , watch the manifold to see if loosing pressure, if not, put more freon in, feel for evaporator to be the "normal cold" stay around 25psi, this method has worked well so far for the vast mojority of problems i encounter,,,

brazing gets better with time and practice.

of course, there will be systems and walls i will hit, and at the point ill raise my level of skill.

You hit the nail on the head about working under supervision. None of us here can actually supervise you while you work. Why don't you hire an HVAC guy to help you over the weekend? You'd actually get answers to the questions you have and you'd have immediate communication and supervision right there. Pay him $25/hour cash. He might do it.

[Walta]

Please note you are required to hold a federal license to work on this equipment.

 

The laws are written to discourage DIY repairs and make legal DIY repairs cost prohibitive.

 

You could be fined $37,000 for each system you work on.

 

Please note anyone that reports you is eligible to receive a $10,000 reward. So publicly bragging about flaunting this law is not a bright idea.

 

Please note the following are violations

1 You may do anything to a system that may release the refrigerant without an EPA approved recovery system on site.

2 You cannot vent any refrigerant to the atmosphere even 134a.

 

Please take the time to read all 4 sections of this link.

 

https://www.epatest.com/609/manual/609_section2.html

 

Walta

[rmorris1953]

melobyrro, on 08 May 2016 - 09:42 AM, said:

 

at my level, i only work with r134, what i do when freezing, open high line, install service valve, suck air out of it with pump, replace dryer just because its cheap and wont hurt, plug deck in, put a bit of gas in, , watch the manifold to see if loosing pressure, if not, put more freon in, feel for evaporator to be the "normal cold" stay around 25psi, this method has worked well so far for the vast mojority of problems i encounter,,,

 

 

 

I am only responding to this because you are in error. I don't want others that don't have any experience to think it is that easy.

 

1. You do not tap the high side of compressor. High pressure can and will blow things up. 125# to 200# is what you will encounter with even more on different refrigrants.

 

2. The driers need not to be replaced unless the compressor has had a burnout or it is plugged. Some may disagree with this statement. Reason being every connection has a possibility of a leak. I don't change them just for that reason. Brazing metal is an art.

 

3. Using just analog gauges won't tell you if you have a leak unless you let them sit for a spell to see if they loose vacuum. Systems should be pressurized with nitrogen to detect leaks before adding refrigerant. The use of a micron gauge is a must.

 

4. Feeling for a "normal cold" isn't the correct assessment. It is a visual assessment mostly Where and how far is the frost line. What is the temp of the evaporator.

 

5. Most important 25 psi is to high on any of these systems. It is overcharged at 25psi with air going through the evaporator and way over with no air. My guess is the person who taught you didn't show you correctly.

 

Hopefully, others reading this don't make the same mistakes you have.

 

Heed Walta's warnings.

 

melobyrro, on 08 May 2016 - 09:42 AM, said:

 

at my level, i only work with r134, what i do when freezing, open high line, install service valve, suck air out of it with pump, replace dryer just because its cheap and wont hurt, plug deck in, put a bit of gas in, , watch the manifold to see if loosing pressure, if not, put more freon in, feel for evaporator to be the "normal cold" stay around 25psi, this method has worked well so far for the vast mojority of problems i encounter,,,

 

 

 

I am only responding to this because you are in error. I don't want others that don't have any experience to think it is that easy.

 

1. You do not tap the high side of compressor. High pressure can and will blow things up. 125# to 200# is what you will encounter with even more on different refrigrants.

 

2. The driers need not to be replaced unless the compressor has had a burnout or it is plugged. Some may disagree with this statement. Reason being every connection has a possibility of a leak. I don't change them just for that reason. Brazing metal is an art.

 

3. Using just analog gauges won't tell you if you have a leak unless you let them sit for a spell to see if they loose vacuum. Systems should be pressurized with nitrogen to detect leaks before adding refrigerant. The use of a micron gauge is a must.

 

4. Feeling for a "normal cold" isn't the correct assessment. It is a visual assessment mostly Where and how far is the frost line. What is the temp of the evaporator.

 

5. Most important 25 psi is to high on any of these systems. It is overcharged at 25psi with air going through the evaporator and way over with no air. My guess is the person who taught you didn't show you correctly.

 

Hopefully, others reading this don't make the same mistakes you have.

 

Heed Walta's warnings.