... lose≤6%2, Freeze Protection: Vacuum can prevent freeze in cold climate,-20 degree3, Working pressure: 2.0 bar for working ... .0 bar for testing, need water feeder or valve connect to existing government cold water4, Safety: even have water in tube, but the ... no damage to the tubes.5, High efficiency and temperature: Water inside will arrive 95 degree.6, Provide enough heat energy ...