Air inlet valve 4000-VFG from TPI-Polytechniek is designed for wider houses requiring an extra supply of air in ventilation. It continues a pattern of development in which the same company introduced air inlet valve type 3000-VFG with double the capacity of its standard inlet 145-VFG. Again bigger than former inlets in the range, the 4000-VFG has a large capacity of about 5500 m3 per hour at a pressure of 20 Pascal when fully opened. The inlet is also more square, giving a relatively short length that allows better control of minimum ventilation.
