1) For the A/C control as per design below to receive dry contact input, it needs to purchase a special unit from manufacturer and is expensive.
2) The control will be cheaper if it is by the RMU provided by the electrical contractor. This RMU can be programmed to control the input from the keycard and the balcony door dry contact (with time delay).
Besides, this balcony dry contact control is not in the original MVAC design dated Feb 2016, why this is added in the VE design? Could you please review the design and advise the amendment?