Can You Use Drainback Systems in Colder Climates?

Drainback System Design for Colder Climates

In colder climates, drainback systems need to be designed to prevent freezing of the collector loop and the drainback piping. This is typically achieved by adding freeze protection to the system, such as a freeze stat or a thermostatically controlled drainback valve. The freeze stat will trigger the valve to open, allowing the water to drain from the collector loop when the temperature falls below a certain threshold.

Freeze Protection Techniques

One common technique is to use a freeze stat with a temperature threshold of around 25°F (-4°C), which is lower than most drainback systems require. This allows the system to drain the collector loop before the water inside it has a chance to freeze. Another technique is to use a thermostatically controlled drainback valve, which can be set to open at a specific temperature to allow the water to drain from the collector loop.

Insulation and Pipe Sizing

In addition to freeze protection, proper insulation and pipe sizing are crucial in colder climates to prevent heat loss and reduce the risk of freezing. The collector loop and drainback piping should be insulated with a minimum of 1 inch (25 mm) of foam insulation, and the pipe sizing should be sufficient to ensure that the water can drain quickly enough to prevent freezing. For example, a 1-inch (25 mm) pipe should be sized to handle a flow rate of at least 2 gallons per minute (7.5 liters per minute) to ensure that the water can drain quickly enough to prevent freezing.