I know that this may sound like I don't know what I am talking about, but it actually is most likely there to protect while in shipping, BUT, just in case it is not only for shipping, I would leave it on unless it contacts something that it would mess up. In either case, it will not hurt the unit in any way for it to be on or off. If it is there for shipping, then it will not hurt to leave it on. if it is there to prevent dirt build-up, then leaving it on is what should be done, but it isn;t going to hurt it either way.

I am not at my shop now at 12:08 AM but if you feel you must have a better answer than that, I can ask my service manager and he will tell me. I have not installed one of these new Hydro's myself as of yet. That is why I hired a service manager and other mechanics, so I wouldn't have to do all of the work myself. since this chance has occurred recently, I will have to ask them. But I have done many units and have NOT seen one of these sleeves on there before.

Let me know if there is anything else that I can do for you. I will be happy to work with you further if needed.

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