| Model | DSA | FSA Series | VSA |
| Connection Type | Multiple | Multiple | Multiple |
| Fan | NA | Integrated | NA |
| Maximum Allowable Pressure | 60 psig (4.1 barg) | 60 psig (4.1 barg) | 60 psig (4.1 barg) |
| Maximum Allowable Temperature | Dependent on operator | Dependent on operator | Dependent on operator |
| Body Material | Cast Iron | Cast Iron | Cast Iron |
Armstrong Electrically Operated On-Off Humidifiers provide direct discharge into atmosphere at steam supply pressures of 2 to 60 psig (4.1 barg). These complete packages use a solenoid valve that turns the steam on and off. Series FSA Humidifiers come with an integral fan with oiless motor to provide rapid, uniform distribution of moisture. Series DSA and VSA Humidifiers are supplied without a fan, and are generally used in parallel with unit heaters.
