Hello,
I worked on a DTG for about 9 months. From time to time I would do the maintenance and printing on it. I was trained, but seeing as i was the shop manager I had a printer on that machine day to day. However, I did get on it frequently. This is all just to say what the heck is the capping hose? Only thing I could think of was the hose on the filter that you would use during maintenance. Maybe If I could get a better idea of what you mean I could provide better help.