BOILER

摘要

Provided is a separatorless boiler the height of an upper header of which is suppressed, that can obtain the desired degree of dryness, and that has a small amount of retained water. The boiler is provided with the following: a boiler body (20) configured so that when combustion using a burner (30) is stopped, the water level inside water pipes (23) is lower than the upper end of the water pipes (23); an external water level detection means (50) that is in communication with an upper header (24) and a lower header (22) and detects the water level inside and outside of the boiler body; and a control means (100) configured so that if the water level detected by the external water level detection means (50) becomes a first set water level, the control means controls the operation of a water providing means (70) so that the water level inside the boiler body (20) is lowered. The boiler is provided with a header water level detection means (60) for detecting the water level that exists inside the upper header (24) due to the boiler water inside the water pipes (23) being forced up by air bubbles produced by the boiling of the boiler water. If the water level detected by the header water level detection means (60) becomes a second set water level, the control means (100) controls the operation of the water providing means (70) so that the water level inside the boiler body (20) is lowered.