Vacuum sustaining heating systems and methods

A heating system integrating a closed-loop, two-pipe vapor vacuum distribution sub-system, comprising:

• a vapor source adapted to generate vapor, the vapor source having a vapor source temperature sensor and a vapor source pressure sensor adapted to sense a vapor source temperature and a vapor source pressure of the vapor from the vapor source;
• a plurality of radiators;
• an up-feeder conduit connecting said vapor source to said radiators;
• a down-return conduit for returning condensate by gravity from each radiator, wherein said down-return conduit contains no steam traps;
• a separator adapted to separate the condensate into liquid and gas phases, and to feed the liquid phase into the vapor source, wherein the separator comprises a gravity return condensate line from the separator via a check valve into the vapor source, and wherein the separator comprises a separator temperature sensor adapted to sense a separator temperature of the condensate at the separator;
• a vacuum pump connected to the separator to evacuate air from the heating system to a preset vacuum interval, wherein the vapor source, the radiators, the up-feeder conduit, the down-return conduit, and the separator are sufficiently air-tight to ensure vacuum pump operation;
• a vapor source control unit for controlling the vapor source based on a building temperature controller, and additionally based on a preset vapor source temperature interval by measuring the vapor source temperature sensed by the vapor source temperature sensor and/or the vapor source pressure sensed by the vapor source pressure sensor;
• and
• a vacuum pump control unit for controlling the vacuum pump based on the vapor source pressure sensor to maintain the preset vacuum interval in the heating system, and additionally based on a preset separator limiting temperature of the separator temperature sensor,
• wherein when the vapor source is on and the separator temperature is below the preset separator limiting temperature, the vacuum pump is turned on, and wherein when the vapor source is on and the separator temperature exceeds the preset separator limiting temperature, the vacuum pump is turned off, thereby switching the vacuum pump off when hot vapor enters the separator and allowing the vacuum pump to remove only air without being exposed to hot vapor.