The FC Series Humidifiers have different port sizes, depending on their size. Those sizes are shown below in the table: “FNPT” Denotes Female National Pipe Thread, which are US-Standard conical threads. We do not recommend using Telflon tape and/or metal fittings to connect with these humidifiers – unless you order the stainless steel versions of the FC 100 and FC 150, which are the only sizes available in stainless steel.
| Series | # Tubes | Standard Ports |
| FC100 | 80 | 1/4″ FNPT |
| FC125 | 240 | 1/2″ FNPT |
| FC150 | 480 | 3/4″ FNPT |
| FC200 | 780 | 1″ FNPT |
| FC300 | 1660 | 1-1/2″ FNPT |
| FC400 | 2500 | 2″ FNPT |
| FC600 | 7000 | 2″ FNPT |