Quick Answer
To drain a hydronic system for winter, use a system blowdown valve or a drain valve to release water from the system, followed by a glycol drain to remove the antifreeze solution, and finally, a thorough flushing with water to remove any remaining debris.
Draining the System
The process of draining a hydronic system typically starts by opening the system blowdown valve, allowing the water to be released from the system. This valve is usually located near the boiler or heat source. The goal is to drain the system to a point where it is below the frost line, which is typically 12-18 inches below the soil surface. If you’re not sure where the system blowdown valve is, consult your system’s manual or contact a professional.
Glycol Drain
Once the water has been drained, the next step is to remove the antifreeze solution, also known as glycol, from the system. This is typically done by opening a drain valve located near the boiler or heat pump. The amount of glycol to drain will depend on the system’s design and the type of glycol used. As a general rule of thumb, you’ll want to drain enough glycol to bring the concentration down to 30-40% of the original amount. This will help prevent corrosion and damage to the system.
Flushing the System
After draining the glycol, the final step is to thoroughly flush the system with water to remove any remaining debris and prevent corrosion. This can be done by opening the drain valve and allowing the system to circulate water through the pipes. It’s recommended to flush the system at least twice to ensure all debris is removed. Once the system is clean, you can close the drain valve and prepare the system for winter storage.
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