1, evaporation pressure is too low:
(1) Insufficient water quantity.
(2) less cold load.
(3) The throttle orifice failure (only low evaporation pressure).
(4) The evaporator's heat transfer pipe due to fouling and other pollution caused by the heat transfer deterioration (only low evaporation pressure).
(5) The refrigerant quantity is insufficient (only causes the evaporation pressure to be too low).
(1) Check the cold water loop, so that the amount of water to reach the rated water.
(2) Check the setting temperature of automatic starting and stopping device.
(3) Check the expansion throttle tube is unblocked.
(4) Cleaning the heat transfer tube.
(5) Supplementary refrigerant to the required quantity.