Dry & Wet Layup Processes for HVAC Systems During Winter

Updated: Dec 1, 2021

by Ben Feeney

Determine the best method to winterize your HVAC system. Dry and wet HVAC system layups.

It’s that strange time of year again when temperatures fluctuate, and HVAC equipment enters a period of intermittent use. Shortly following this shoulder season is the winter shutdown.

Water treatment plays an important role in minimizing corrosion and deposit formation during both these periods. Selecting the right combination of chemical and mechanical layup methods for your facility can help save time, energy, and efficiency when spring start-up approaches.

Shoulder Season

Does your system stay off for several hours each day during the fall? The Association of Water Technologies (AWT) emphasizes the importance of running pumps for at least one hour for every six hours offline. This prevents stagnation and solids from settling, which can damage cooling equipment and piping. Often, chillers that are opened show poor results due to this period of stagnation.


Ahead of chiller layup, it’s vital to disinfect the system.