As someone who spent 7 years installing, repairing and maintaining Cornelius frozen carbonated beverage machines in 7-Eleven and other convenience stores, theatres and even outside fairs and festivals, I think I can offer some helpful tips for those looking to buy a used FCB machine. These tips are meant to address older model Cornelius machines that are commonly advertised on the internet, manufactured from 1989 to 2002, but may apply to newer machines as well. Please consult the manufactures web site or local service providers for your specific model.
Most people already know what a slurpee is but there is a big difference between a slushy and a slurpee when it comes to the product and the equipment that produces it. A slurpee is a frozen carbonated beverage (FCB). A slushy is a frozen non-carbonated beverage (FNCB). 7-11 is known as one of the biggest sellers of FCB's. Your average slushy (FNCB) freezes a mixture of flavored syrup and water and produces a slush that has a wet and heavy look and a coarse, icy consistency. Most FNCB machines are small counter top units. The product is usually manually prepared and added to the freezing container as needed. An FCB machine is larger and comes in floor and counter top models. An FCB machine freezes a mixture of flavored FCB syrup, which is specifically designed for FCB machines, and carbonated water. All modern FCB machines are fully automated. Water is carbonated and blended with FCB syrup on demand. As frozen product is dispensed it is automatically replaced with an equal amount of the blended mixture and refrozen. A properly produced slurpee should have a light, dry look and a creamy consistency.
Some things buyers should be aware of when shopping for a used Cornelius FCB machine are the model, age, past operating environment, electrical and plumbing requirements, and repair and maintenance cost. All machines have an ID sticker or plate on the front, usually right behind the cup/drip tray. The tray is easily removed for cleaning so the model number and date of manufacture can be easily accessed as well. Depending on the operating enviornment, age is a very important factor. A well maintained machine from a warm southern state may operate 24/7, 365 days per year and last only 5-7 years as opposed to one from a northern state which may be turned off on cold days and evenings and during winter months and last 8-12 years or more.
A 2 flavor Cornelius FCB machine requires a minimum 30 amp circuit breaker, 208 volts, single phase electrical supply. The 4 flavor models require a 50 amp circuit breaker. Some 2 and 4 flavor models manufactured in the early 1990's and before require a minimum of 219 volts and will have problems if the voltage is too low. Stores that had these particular machines required a buck-n-boost transformer for the machine to operate correctly. By obtaining the model number, you should be able to contact the manufacturer to obtain the year of manufacture as well as the power requirements.
The machine will also need a minimum 3/8 id water supply line and no less than 50 psi of water pressure. Anything less will create inconsistent water/syrup mixtures. Water pressure and supply line id may need to be increased on long runs.
What you generally don't hear about when buying a used FCB machine is the maintenance and repair costs. That's most likely because some vendors are merely resellers and may have no service knowledge. Again, your maintenance costs will be pretty much based on the operating environment and how you use the machine. The recommended maintenance schedule (and my experience proves this to be true) for a 2 flavor machine operating 365 days a year will require a minimum 2 basic and 1 full preventive maintenances per year. The basic maintenance includes replacing rear o-rings, re-lubrication of rear seal components and the dispensing valves, re-brixing (water/syrup ratio adjustment), re-calibration of the freeze times, inspection of the electrical components (contactor, start/run capacitors) and general cleaning. A basic pm should take an experienced tech approx 1.5 - 2.5 hours. The full maintenance includes a basic maintenance as well as replacement of the beater body and blades inside the freeze chamber and shouldn't require much more time than the basic maintenance. Parts and labor prices will obviously vary from place to place but I estimate a basic pm on a 2 flavor machine to run between $125 - $250 and add another $100 - $150 for a full pm. Keep in mind that other parts not included in these pm's can and do fail from time to time and will add to your annual maintenance cost.
One other note, I have found that these machines do not operate well in hot, unventilated areas of 90+ F degrees. Freeze times can take longer, beater motors and compressors can overload and trip off, and main circuit breakers can trip.
A Cornelius FCB machine that is installed, set-up, and maintained correctly will function well for many years and will produce a consistent superior quality beverage. I hope this information helps those of you in the market for a used FCB machine.