The invention relates to a dish-shaped 
flame low-
nitrogen negative-pressure hot water unit and an operation method thereof. The dish-shaped 
flame low-
nitrogen negative-pressure hot water unit is provided with an 
enclosure; a 
combustor is arranged at the front end of the 
enclosure; the 
combustor is provided with a 
fuel gas inlet, an air inlet and a 
smoke inlet; the dish-shaped 
flame low-
nitrogen negative-pressure hot water unit is provided with a 
gas mixing chamber, and a 
spinning disk is arranged in the 
combustor; a 
combustion chamber and a water-cooling wall are arranged in the 
enclosure, anda circulating water tubulation is arranged at the rear part of the combustor; the upper part of the circulating water tubulation is provided with an upper space , the water-cooling wall, the circulating water tubulation and the upper space are all fully filled with circulating water; a heat exchange tube is mounted in the upper space, the heat exchange tube is filled with external supply hot water, and a 
smoke discharge pipe is arranged at the other side of the circulating water tubulation, which is opposite to the 
combustion chamber; a gas extraction device for enabling a circulating water 
system to be kept under a negative pressure is arranged at the upper space; moreover, the dish-shaped flame low-nitrogen negative-pressure hot water unit is provided with an explosion-proof device. Inaddition, the dish-shaped flame low-nitrogen negative-pressure hot water unit is provided with a PLC (
Programmable Logic Controller) and a plurality of sensors and an 
automatic control frequency converter which are in 
signal and control connection with the PLC. The dish-shaped flame low-nitrogen negative-pressure hot water unit adopts dish-shaped flame low-nitrogen negative-pressure manual or 
automatic control operation, is perfect and reasonable in structure and has the obvious advantages of high efficiency, energy saving, environment protection, safety and automatic operation.