One of the most common myths about nodules is the diagnosis itself! Usually doctorâs donât have the necessary equipment (stroboscopy) to diagnose vocal problems. So all problems are called nodules. Every singer has a colleague who had ânodulesâ for this reason.
An RTU is a type of AHU. AHU stands for Air Handling Unit and the acronym RTU means Rooftop Unit. The Roof Top Unit is an outdoor AHU. As RTUs are mounted on the roof, there is no concern about creating extra space indoors for it as would be the case for the other types of AHU.
FCU is fan coil unit which is intalled for samll capacities and have less options than AHU like no humidity control and no special options for heat recovery of air filters. AHU means Air Handling Units and are available in number of varities and tonnages from small upto large capacities.