Abstract: In a second tank unit, a controller controls the on/off switching of a water supply solenoid valve so that water is stored in a sub tank within the level of Lu to Ll. At the same time, the controller controls the on/off switching of a pressurizing solenoid valve and a decompressing solenoid valve so that the air pressure in the upper space in the sub tank is maintained at a target value. As a result, regardless of the water level in the sub tank, the back pressure in the tank is maintained at the target value higher than atmospheric pressure. In this state, when a central controller turns on a water spouting solenoid valve, pressured water rapidly spouts from a nozzle. Moreover, a change in the target values of the back pressure promptly changes the height of the spouting water. Accordingly, water spouting can be promptly started/stopped, and the height or size of the spouting water can be readily and smoothly changed.

Abstract: In a second tank unit, a controller controls the on/off switching of a water supply solenoid valve so that water is stored in a sub tank within the level of Lu to Ll. At the same time, the controller controls the on/off switching of a pressurizing solenoid valve and a decompressing solenoid valve so that the air pressure in the upper space in the sub tank is maintained at a target value. As a result, regardless of the water level in the sub tank, the back pressure in the tank is maintained at the target value higher than atmospheric pressure. In this state, when a central controller turns on a water spouting solenoid valve, pressured water rapidly spouts from a nozzle. Moreover, a change in the target values of the back pressure promptly changes the height of the spouting water. Accordingly, water spouting can be promptly started/stopped, and the height or size of the spouting water can be readily and smoothly changed.