Does the boiler have a low water cut off?

No, but the boiler operates in much the same way as low water cut off. The boiler has a pressure sensor installed. It will not operate when the pressure level falls below 7 psi. This will protect the heating elements from being dry fired which can lead to failure. However there are other safeguards in place to prevent element failure. Some municipalities require a low water cut off at the highest point in the radiant system. Consult with local authorities if this is a requirement in your market.