Dimensions and duct outlets Figure 1. Dimensions and duct outlets Duct outlets, R model s 1 Supply air from the unit to the apartment 2 Extract air from the apartment to the unit 3 Exhaust air flowing outdoors from the unit 4 Outdoor air to the unit Figure 1. Dimensioning figure and space required for installation of the Vallox Silent Klick siphon A Service space B Power plug cord C Siphon D Alternative siphon E Space required for installation Figure 3. Condensing water outlet dimensioning (Vallox TSK Multi 50 MV)