I have a Mitsubishi mini split that was installed last fall and we used it for heating over the winter and now when we started using it for cooling I've noticed a vinegar smell coming out of it. We have 5 zones but only one smells. Air filters and heat exchanger are clean, Mitsubishi tech support suggested I call the insrltaller and the installer never heard of anything like this. He's coming over to take a look on Friday but if any of you have some idea what's causing it or have experienced this, please let me know. Thanks!