I was shift manager for McDonald’s during high school. We were suppose to clean them every two weeks(Saturday). The whole cleaning and maintenance process was suppose to take about 7 hours. From cleaning, adding fluids, and adding some lubricant to parts. However I only had two hours to do everything. The machine we had cost $18,000. They are super sensitive. If you don’t add the proper amount of ice cream the machine can’t go into heat mode. Heat mode is suppose to happen overnight because the process would take somewhere around 5-8 hours to kill of any bacteria. You can’t make shakes or dispense ice cream if this process doesn’t happen and it will tell you do either do the heat mode again or clean the machine. Hints why it’s always down. At least for us. Machine was about 8 years old when I was there. However if you take an actually ¢Penny you short something in the back into tricking the machine that you cleaned it. After a while it will act up to the point of no fix. We would call the tech. Tech charges about $100 dollar per hour and fee to show up. McDonald’s themselves don’t pay for the service, the franchise owners pay. They hate paying. Sorry for my English. It’s not my first language.