Hey, everybody. This is John McCoy, production manager here at G&D Chillers. We’re going to address glycol level under normal operating circumstances. Depending on the style of glycol chiller you buy from us, there’s two different types of sight glass you’ll see on the reservoir. One of them is a window cut-out on our poly tanks. On our stainless tanks, there’s going to be an actual sight glass. It’s a clear piece of tube that allows you to see the level inside the system. Typically, you want to see that reservoir about two-thirds full at all times during the normal running process. You can have a little bit of wiggle room there but we really want to make sure that you’re maintaining at least two-thirds at all times inside your glycol reservoir. Contact Us