I don’t have a book on it but I do have the same system. Those are sight glasses for metering your high pressure soap and wax. one glass per bay. If it is like mine, follow the lines from your hp soap and wax tanks, they should go to a manifold and split depending on your number of bays. Each line will go up to a solenoid, probably mounted right under the sight glass. From there the hp soap and wax lines should meet and go through the sight glass. The line off the top of the sight glass that you had that was cut should then run down to your pump. The sight glass shows how much soap or wax is going to the bay. Right below the sight glass,on the bottom of the box looking at the front of the unit you will see the set screws that set the metering of product to the bays. When it is plumbed correctly, or at least like mine, when the bay is running on hp soap or wax you will see the product moving through the sight glass and going down to the pump. There is a ball in the sight glass that will float and indicate how much product is passing through to the pump. When the bay is running you can adjust the set screw and the ball will rise or fall showing how much product is passing to the pump. Hope that helps.
