My soda machine is freezing up and then not cooling. It starts at the left side on the small copper line and then if left plugged in will also freeze the big line and then the fins behind the lines. What is causing this?

Could you get the model # of the machine? It sounds like you could have a thermostat issue.

i believe it is made by legacy vendors the model # is 3040

Could you get the model # of the machine? It sounds like you could have a thermostat issue.

You have a few possibilities.

First, check the simple stuff. Make sure that the evaporator fan is running and there is good air flow. Next, make sure that the condensation drain is not clogged.

To check the thermostat, umplug the machine and crank the thermostat up and down. You should hear a clicking noise. If you still suspect the thermostat, unplug it and put a continuity meter across the contacts and crank it again. The continuity should open and close coinciding with the clicks.

Some drink machine models have a defrost cycle. That is why the model info is important but it isn't very common for them to have defrost.

So, after you've checked those things, my guess is that you are getting low on freon and need a recharge. From my experience, that's the most common cause of coils freezing over.

You have a few possibilities.

First, check the simple stuff. Make sure that the evaporator fan is running and there is good air flow. Next, make sure that the condensation drain is not clogged.

To check the thermostat, umplug the machine and crank the thermostat up and down. You should hear a clicking noise. If you still suspect the thermostat, unplug it and put a continuity meter across the contacts and crank it again. The continuity should open and close coinciding with the clicks.

Some drink machine models have a defrost cycle. That is why the model info is important but it isn't very common for them to have defrost.

So, after you've checked those things, my guess is that you are getting low on freon and need a recharge. From my experience, that's the most common cause of coils freezing over.

I find this very interesting, Not to be a smart ass but if it takes freon to cool the tubes to make cold air how can it freeze up without freon? I personally can't get anything to freeze without freon. Just a another one of my stupid thoughts.
Vend1ng

My soda machine is freezing up and then not cooling. It starts at the left side on the small copper line and then if left plugged in will also freeze the big line and then the fins behind the lines. What is causing this?

If the whole coil freezes up solid if left on then it will be t-stat, evap fan, or air leak (i.e. door seal, vend port door, etc).
If only part of the coil is freezing up starting at the small tube going into the big tube and depending on the tube configuration it is caused by low freon. If it is low freon you will have some ice build up with lots of moisture in the machine. If t-stat you'll have lots of ice and none to very little moisture. Just a thought.
Vend1ng

I ordered a new t stat and i am going to install it tonight.

I find this very interesting, Not to be a smart ass but if it takes freon to cool the tubes to make cold air how can it freeze up without freon? I personally can't get anything to freeze without freon. Just a another one of my stupid thoughts.
Vend1ng

It's one of those quirks with refrigeration. It's not out of freon, just low on freon.

When the pressure in the low pressure side (evaporator coils) is too low, the freon boils too quickly is certain areas of the coils and not at all in other areas. This causes the coils to act ineffeciently and, overall the machine won't chill properly. A good sign of this happening is that the machine will run continually without reaching its target temperature. The reason I suppose that this is happening here is that the frost keeps building. Any frost should thaw after the unit reaches the target temperature and the compressor cuts off.

So, those areas where the freon boils too quickly will start to frost up. The frost acts as an insulator which slows down the boiling in that particular area of the coils and also inhibits the heat exchange there. This causes the the ultra cold spots and frost to spread. As the frost spreads and grows, it restricts air flow. The restricted air flow causes the frost to spread more quickly and build more quickly. It snow balls, so to speak.

When a machine is properly charged, the freon boils evenly across the evaporator coils; the machine operates more efficiently, it cycles properly, and any frost that may accumulate melts during the cycle.

When you're charging a machine, the specs will tell you how much freon to put in one. It's very difficult to inject the right amount by just measureing the stuff because you never know just how much you have in your hoses. So, if you're charging an empty (of freon) machine, you cut off the evaporator fan, run the system, and add the recommended amount. As you start to add, frost will appear where the capillary tube (that tiny little copper tube) enters the evaporator coils. As more freon enters the system, frost will usually form on the ends of the evaporator coil tubes and will usually remain there as the system runs and you've added -as best as you can tell- the recommended amount. Then you slowly add a little more and a little more until that frost melts. That's how you know you've reached the proper charge.

If you're charging a partially charged machine, then you just keep adding little bits more until that frost melts.

It's one of those quirks with refrigeration. It's not out of freon, just low on freon.

When the pressure in the low pressure side (evaporator coils) is too low, the freon boils too quickly is certain areas of the coils and not at all in other areas. This causes the coils to act ineffeciently and, overall the machine won't chill properly. A good sign of this happening is that the machine will run continually without reaching its target temperature. The reason I suppose that this is happening here is that the frost keeps building. Any frost should thaw after the unit reaches the target temperature and the compressor cuts off.

So, those areas where the freon boils too quickly will start to frost up. The frost acts as an insulator which slows down the boiling in that particular area of the coils and also inhibits the heat exchange there. This causes the the ultra cold spots and frost to spread. As the frost spreads and grows, it restricts air flow. The restricted air flow causes the frost to spread more quickly and build more quickly. It snow balls, so to speak.

When a machine is properly charged, the freon boils evenly across the evaporator coils; the machine operates more efficiently, it cycles properly, and any frost that may accumulate melts during the cycle.

When you're charging a machine, the specs will tell you how much freon to put in one. It's very difficult to inject the right amount by just measureing the stuff because you never know just how much you have in your hoses. So, if you're charging an empty (of freon) machine, you cut off the evaporator fan, run the system, and add the recommended amount. As you start to add, frost will appear where the capillary tube (that tiny little copper tube) enters the evaporator coils. As more freon enters the system, frost will usually form on the ends of the evaporator coil tubes and will usually remain there as the system runs and you've added -as best as you can tell- the recommended amount. Then you slowly add a little more and a little more until that frost melts. That's how you know you've reached the proper charge.

If you're charging a partially charged machine, then you just keep adding little bits more until that frost melts.

I'm not sure how to even reply to this, But since other people read this for reference I will just say "There are no quirks of refrigeration its not magic it is very logical" There are so many wrongs in your statement I don't know how to address them all. I will list a few facts:
You cannot freeze the entire evap coil without a full charge of freon.
You can have some ice build up on a small portion of the evap coil (generally the upper right hand corner on a dixie-narco)when low on freon.
Logically: A dixie-narco has 10 oz of freon in a system that is probably designed to 125% of its neccessary capacity so it can opperate at varing conditions. We try to maintain about 36-38 degrees for cold pop. Since we have about a +25% capacity we can probably maintain that temp with only 8oz of freon with a longer run time and shorter off time.If you drop to 5oz of freon that is half the capacity of the evap coil and it would probably about 48 to 50 degree pop that is when the customers will start complaining about the pop not being cold enough. Thats not cold enough to satisfy the t-stat. Compressor will run continually and ice may form on the first 1/4 of the evap coil. So yes it is possible to determine how much freon is in a system logically. Freon doesn't wear out. If it is low on refrigerant it has a leak by law the leak must be repaired and recharged. By law if I charge for freon by the ounce or pound I have to have a way to weigh it that is about all the scales are good for. When charging a system turn evap fans off frost suction line (big tube) back to the break over point (where the line goes from cold box to warm box). You have a plus or minus from that distance to the compressor. Do not frost back to compressor or you may damage the compressor. Stopping frost line at break over point keeps condensation from dripping on customers floor. If evap lines start defrosting while charging you probably over charged the system. Thats just my thoughts after doing about 10,000 compressors in my career.
Vend1ng

I'm not sure how to even reply to this, But since other people read this for reference I will just say "There are no quirks of refrigeration its not magic it is very logical" There are so many wrongs in your statement I don't know how to address them all. I will list a few facts:

Explain that to the machine I just topped off last week. The coils would freeze solid is two days after I would thaw them out. Hasn't frozen since I topped it off.

Or ask Inspectepedia:"When the surface of a cooling coil or suction line drops below 32 degF (say from too little refrigerant in the system or too little flow of warmer air across the cooling coil) frost formation is likely on that surface."
Reference:http://www.inspectapedia.com/aircond/ACCoilFrost.htm

Or try Yahoo answers:http://answers.yahoo.com/question/index?qid=20070731190839AA51MXE

Here's one from DIY Chat room: http://www.diychatro...icing-up-45255/
"Because it takes X amount of time for it to freeze/ice up the lower portion where you see the frost.
Once that portion becomes ice.
The liquid refrigerant can travel further up the coil and freeze it also.

Find and fix the leak. "

My t-stat did not show up yesterday, but after re reading all of this I started to think maybe I don't know what the evaporator fan is. I have only found one fan and it is in the very bottom of the machine in front of the compressor. Is there another fan above, that is in the cold area of the machine? If so how do I get to it? I have had this thing unplugged for two days and yesterday just for grins I plugged it back in and within 20 minutes the small 1/4 inch copper tube had frosted up for about the first 6" on the left hand side if you were looking into the machine from the open door.Yes I did have the machine closed for the 20 minutes it was running. Can it freeze that quickly from bad thermostat?

The evaporator fan is behind the evaporator coils and should be running constantly, independant of the compressor. Even if you can't see it, you should be able to hear it and feel the air flow. The only way to get to it is to pull the coils out.

Try this. Plug the machine in and let it run for a minute. The compressor and compressor fan should be running. Now turn the thermostat down and see if the compressor/fan shuts off. If that happen your thermostat is probably OK.

If the compressor and compressor fan is off, you should still hear the evaporator fan running. If the machine is quiet than that is your problem. Then your task will be to determine why it isn't running.

So the evaporator coil is the long set of coils that are in the cooled area of the machine right behind the copper tubes? Can I remove them without losing freon? How do I do that? Sorry for my ignorance, I know nothing about refrigeration, but it looks like I'm fixing to learn!

The evaporator fan is behind the evaporator coils and should be running constantly, independant of the compressor. Even if you can't see it, you should be able to hear it and feel the air flow. The only way to get to it is to pull the coils out.

Try this. Plug the machine in and let it run for a minute. The compressor and compressor fan should be running. Now turn the thermostat down and see if the compressor/fan shuts off. If that happen your thermostat is probably OK.

If the compressor and compressor fan is off, you should still hear the evaporator fan running. If the machine is quiet than that is your problem. Then your task will be to determine why it isn't running.

Explain that to the machine I just topped off last week. The coils would freeze solid is two days after I would thaw them out. Hasn't frozen since I topped it off.

Or ask Inspectepedia:"When the surface of a cooling coil or suction line drops below 32 degF (say from too little refrigerant in the system or too little flow of warmer air across the cooling coil) frost formation is likely on that surface."
Reference:http://www.inspectapedia.com/aircond/ACCoilFrost.htm

Or try Yahoo answers:http://answers.yahoo.com/question/index?qid=20070731190839AA51MXE

Here's one from DIY Chat room: http://www.diychatro...icing-up-45255/
"Because it takes X amount of time for it to freeze/ice up the lower portion where you see the frost.
Once that portion becomes ice.
The liquid refrigerant can travel further up the coil and freeze it also.

Find and fix the leak. "

"Explain that to the machine I just topped off last week. The coils would freeze solid is two days after I would thaw them out. Hasn't frozen since I topped it off."Lets look at this:
If your right:
1.You just added freon to a system that has a leak ..... you'll get to do that again.(plus thats against the law).
2.When you have a leak its either on the suction side or the high side, If its on the suction side you've sucked air into the system, air and freon don't mix. If its on the high side you'll get to add freon sooner.
3. If you sucked air into the system and didn't change filter drier you just contaminated the filter drier.
If I'm right:
1. You just over charged the system pushing liquid back into the compressor ... your going to get to change out a compressor.
2. The pop in the machine will be cool at best.
3. Once you change out the compressor you'll find you need to replace the t-stat.
Now you have spent 300.00 wholesale or 650.00 retail when all you needed was a t-stat.
For those that want a simple way to determine low freon, t-stat, bad compressor:
Disconnect evap fan(s) turn compressor on if lines frost anywhere past the accumalator you have plenty of freon and the system is working. If t-stat should shut off compressor at any time doing this its working. I don't know how to put it any simpler, It takes freon to make frost,or ice not magic not quirks not BS theories. Since the beginning of time ice is cold no ice is not cold. An evaporator is a big block of ice created chemically when you need it. If its a big block of ice the size of the evap coil it has lots of freon if its a small block of ice less than the size of the evap it doesn't have enough freon. Simple chemical reaction, expansion, contraction, horse power, current, capacity, volume, flow, BTU's, pressure, suction,thats designed by engineers repaired and improved by those that know better. Just a thought.
Vending

Right. The evaporator coils are located within the fins described in your initial post and are all connected to those copper tubes. Before you pull the coil, did you check for air flow? If there is flow, that's not your problem. If there is none, you can do a couple of checks before you get into pulling the coils.

If you put your hand across the fins, you should feel a slight suction. If you reach behind and above the coils, you should feel the blowing. Be careful because the fan may not always be properly shrouded and it can cut your hand if you come in contact.

If there is no air flow, then check that the fan is getting power. There is an electrical line that runs from a junction under the machine to the fan. It may be bundled with the copper tubes that run from the bottom and is about the size and thickness of a household extension cord. There will often be a plug somewhere in that line. Pull the plug and put a multi-meter to the feed side to make sure it is getting power. Then put the ohm-meter part to the motor side to check continuity. You should get some resistance but off the top of my head, I couldn't tell you what it should be. If the circuit is either open, or there's little to no resistance, there's a problem with the motor.

I've never pulled the coils on that type of machine but it can be done. They are usually attached to the fan shroud by some screws on the ends. Unless someone wants to step in and give more accurate instruction on that particular machine, I will say that you can do it by just taking your time. The copper lines will bend some just be careful not to bend them a lot. The fins can be sharp so be careful not to cut yourself. Also, the fins are delicate so be careful not to bend them.

P.S. Did you check the condensation drain? From what you describe that doesn't sound like your problem but it's one of those easy things to check. When you thaw the machine, does the water drain out the back or does it pool up and drain out the front?

Last night I pulled the condensation drain loose and cleaned it rel good,but that made me have a thought. If the machine was not level could that cause this problem?

Right. The evaporator coils are located within the fins described in your initial post and are all connected to those copper tubes. Before you pull the coil, did you check for air flow? If there is flow, that's not your problem. If there is none, you can do a couple of checks before you get into pulling the coils.

If you put your hand across the fins, you should feel a slight suction. If you reach behind and above the coils, you should feel the blowing. Be careful because the fan may not always be properly shrouded and it can cut your hand if you come in contact.

If there is no air flow, then check that the fan is getting power. There is an electrical line that runs from a junction under the machine to the fan. It may be bundled with the copper tubes that run from the bottom and is about the size and thickness of a household extension cord. There will often be a plug somewhere in that line. Pull the plug and put a multi-meter to the feed side to make sure it is getting power. Then put the ohm-meter part to the motor side to check continuity. You should get some resistance but off the top of my head, I couldn't tell you what it should be. If the circuit is either open, or there's little to no resistance, there's a problem with the motor.

I've never pulled the coils on that type of machine but it can be done. They are usually attached to the fan shroud by some screws on the ends. Unless someone wants to step in and give more accurate instruction on that particular machine, I will say that you can do it by just taking your time. The copper lines will bend some just be careful not to bend them a lot. The fins can be sharp so be careful not to cut yourself. Also, the fins are delicate so be careful not to bend them.

P.S. Did you check the condensation drain? From what you describe that doesn't sound like your problem but it's one of those easy things to check. When you thaw the machine, does the water drain out the back or does it pool up and drain out the front?

WOOOOHOOOOO!!!!!!!! Fixed it!!!!!!! Thanks to everyone for their help. I have learned quite a bit!! The machine was an inch lower in front than in back and I assume the condensation was not draining. It has now ran for about 4 hours without freezing up and it is cooling!!! Thanks again for all the replys.

well I went ahead and changed the thermostat since I had already ordered a new one and it ran good for about 4 days, very little frost on lines. Then this morning it has quit cooling all together. Acts like compressor isn't even coming on. Does that sound like freon??

this machine is a USI model 3040. I have a dixie narco model 368 that all of the cooling equiptment works great. Can I just switch the entire compressor deck? Will everything bolt up correctly?

well I went ahead and changed the thermostat since I had already ordered a new one and it ran good for about 4 days, very little frost on lines. Then this morning it has quit cooling all together. Acts like compressor isn't even coming on. Does that sound like freon??

No, The compressor will run without freon .....You need to determine if compressor is running .... Is the condensor fan running (fan next to compressor)? Is the condensor or compressor hot?
Vend1ng

this machine is a USI model 3040. I have a dixie narco model 368 that all of the cooling equiptment works great. Can I just switch the entire compressor deck? Will everything bolt up correctly?

No!
Vend1ng