Can the positive pressure of central air conditioning in Changsha Yuanda, Hunan be added?

The solution can only be added when the central air conditioning in Changsha Yuanda, Hunan Province is positive pressure. The working principle of Yuanda central air conditioning in Changsha, Hunan Province is to transfer heat through gas-liquid two-state conversion. The solution inlet is positive pressure and the outlet is negative pressure, so the solution can only be added under positive pressure. Therefore, the positive pressure of central air conditioning in Changsha Yuanda, Hunan Province can be solved.