Is Your Chiller Ready for Winter? A Cold-Weather Checklist for Glycol Chillers October 22, 2026 Most chiller problems people plan for happen in summer, when high temperatures push a system to its limits. Winter causes a different set of problems, and they’re easier to miss, because a chiller often looks like it’s running fine right up until it isn’t. Why cold weather is hard on air-cooled chillers An air-cooled chiller rejects heat to the outdoor air. When that air gets very cold, the condenser can reject heat too well. Head pressure drops, refrigerant flow through the expansion valve falls off, and the system can lose capacity, short cycle, or trip on low pressure. That’s what low-ambient controls are for: they cycle or slow the condenser fans, and on some systems regulate head pressure, to keep the refrigeration circuit stable when it’s cold outside. At the same time, anything carrying fluid outdoors is at risk. If glycol concentration has drifted or a section of piping isn’t protected, a hard freeze can split a line or damage a heat exchanger, and that’s a repair nobody wants to schedule in January. (For more seasonal tips from our team, see our post on chiller winter tricks & tips.) The winter checklist ☐ Check your glycol concentration. Over time, water top-offs, small leaks, and maintenance dilute glycol. Measure it with a refractometer (most G&D chillers ship with one) and compare the reading to your system’s design spec. Too little glycol raises freeze risk. Too much reduces heat transfer and makes pumps work harder. If you’re not sure what your spec should be, our tech support team can help. Our essential chiller maintenance tips cover glycol mixtures in more detail. ☐ Confirm your low-ambient controls are working. Watch the system on a cold morning. The condenser fans should cycle or slow down to hold pressure. If the compressor short cycles or trips on low pressure in cold weather, have it checked before the deep cold arrives. ☐ Test freeze protection and alarms. Verify that freeze protection, high and low pressure controls, and high temperature alarms respond the way they should. An alarm that doesn’t trip is worse than no alarm at all, because it creates false confidence. ☐ Inspect outdoor piping and insulation. Look for insulation that’s damaged, missing, or waterlogged, especially around valves, unions, and fittings. Wet insulation doesn’t insulate. ☐ Plan for holiday coverage. Many facilities run with a skeleton crew in late December. Make sure alarm notifications go to someone who is actually on call, and that contact lists are current. If your chiller has remote monitoring, confirm alerts are reaching the right phones. ☐ Think about critical spares. Shipping slows down over the holidays. Consider which parts would stop production if they failed, and whether it makes sense to keep one on hand. Don’t forget the load side Winter often brings lighter process loads, whether that’s a brewery’s slower season or a winery after crush. A light load combined with cold outdoor air is when short cycling is most likely. If your production slows down this time of year, it’s worth checking whether your setpoints and staging still fit how you’re actually running. Signs it’s time to call Call for help if you see the compressor short cycling, low-pressure trips on cold mornings, frost or ice forming on piping, a low glycol reading, or unusual noises at startup. Catching these early is the difference between a quick adjustment and an emergency repair. And if this winter is when you’re planning to replace or add a chiller, the slower season is a good time to start that conversation too. Take a look at our glycol chillers to see what’s available. Need help with a glycol check or your winter setup? Our tech support team is available 24/7. Contact Product Support →