The steam valve, activated by the lever at right or left with the red knobs, is an electrically activated solenoid valve with a large passage. This solenoid valve is either fully open, or closed.
To adjust the steam flow/power there is an extra, horizontal lever. When adjusted, the activating lever opens the valve always immediately at the preferred flow. When necessary, the flow/power can still be adjusted on the fly by the horizontal lever. The hot water lever, in the centre with red knobs, activates two solenoid valves simultaneously. Hot water from the steam boiler passes through one valve, the other supplies cold water. A pump runs during the supply of cold water. Cold water supply is restricted by a jet under the solenoid valve.This mix of hot and a bit of cold water results in a steady, non-spattering stream from the hot water spout.
The temperature of this mix can be managed by adjusting the pressure of the pump. A lower pressure supplies less cold water, resulting in a higher temperature from the spout. A higher pressure supplies more cold water to the mix, this results in a lower temperature. The pump pressure can be adjusted over a wide range, so the temperature of the hot water can be tuned accurately.
To ensure the hot water is always at identical temperature, the machine is programmed to not activate re-filling the steam boiler during hot water supply, as this would cause a slight drop in pump pressure, resulting in a slight raise in temperature of the hot water.