Pipe freeze protection for nest

[eki]

When the outdoor air temperature (OAT) drops below freezing, a hydronic heating system becomes vulnerable to freezing. If the thermostat enters an energy-saving eco mode or lowered temperature set point schedule, it may delay calling for heat for several hours, increasing the risk of the water in the system freezing and potentially causing pipes to burst. It would be beneficial if the Nest algorithm included an option to automatically and periodically call for heat—such as for a set duration every 30 minutes or hour—but only when the OAT drops below freezing and regardless of the set temperature. While this feature might consume more energy, it would be a much better alternative to dealing with frozen pipes and the resulting water damage.

[Patrick_Caezza · Accepted solution]

@eki 

The Nest thermostats do have a Safety Temperature setting. Look at this link to see if this is what you are looking for.

Thermostat Safety Temperatures 

[eki]

The safety temperature alone is insufficient to prevent hydronic heating pipes from freezing, as it often takes several hours for the indoor temperature to drop low enough to activate the safety setting. By that time, the pipes may already have frozen. However, setting the thermostat to call for heat for 5 minutes every 30 minutes can effectively reduce the risk of pipe freezing without significantly raising the indoor temperature.