1. The air in the economizer and condenser has not drained yet when firing. The safety valves of economizer and condenser need to be turned on to exhaust steam. Return pipe valves also need to be turned on, enabling the steam in the economizer and condenser to return to softened water tank.

2. The outlet water temperature is so high that economizer and condenser will have vaporization phenomenon. The outlet water temperature of economizer and condenser need to be controlled.

3. The check valve of the inlet of economizer and condenser is not at normal conditions. The check valve needs to be repaired.