Series-401Configuration

Supported Applications

The Dwyer Series 401 Magnetic Liquid Level Controls are top-mounting devices designed for pressurized or non-pressurized tanks and sumps. These heavy-duty controls utilize a magnetically actuated switch mechanism operated by a float to manage high and low liquid levels. The series supports single-stage (Type 401-1) and two-stage operations (Types 401-2, 401-3, 401-4), providing configurations for pump operation combined with high or low alarms, shutdowns, or dual alarm functions.

Operating Conditions & Performance

The Series 401 operates in environments requiring robust pressure and temperature ratings. The series supports process temperatures from -20 to 500°F (-29 to 260°C) with an ambient operating limit of 212°F (100°C). Pressure capabilities vary by float material, offering up to 600 psi at 500°F MAX. for specific stainless steel configurations.

Measurement ranges extend to depths of 12 ft., accommodating fluids with a specific gravity from 0.50 to 1.0. Operating depth limits and guide rod lengths are dependent on the float size, material, and fluid specific gravity; critical dimensions must be verified with the factory before placing an order.

Pressure and Temperature Ratings by Float Type

• 4-1/2" Copper: 150 PSI @ 300°F MAX.
• 4-1/2" 304 S.S.: Available at 300 PSI or 600 PSI, both rated to 500°F MAX.
• 7" 304 S.S.: Ratings include 450 PSI @ 100°F MAX., 425 PSI @ 200°F MAX., and 300 PSI @ 500°F MAX.
• 3-1/2" x 6" S.S.: Available at 300 PSI or 450 PSI, both rated to 100°F MAX.

Configuration Options

The Series 401 is configurable across multiple dimensions including enclosure type, switch mechanism, flange assembly, and float material. The series supports various NEMA ratings depending on the selected housing:

• G (General Purpose): NEMA-1.
• WT (Watertight-Dusttight): Suitable for NEMA 1, 2, 3, 4, and 4X.
• E (Explosion-Proof): NEMA 7, 9; Class I Groups B, C, D; Class II Groups E, F, G, Division I and II. CSA approved for Groups C, D, E, F, G only.
• EV (Vapor Proof-Explosion-Proof): NEMA 7, 9; Class I Groups B, C, D; Class II Groups E, F, G, Division I and II.

Switch options include mercury contacts or snap action contacts with Single Pole Single Throw (SPST), Single Pole Double Throw (SPDT), and Double Pole Double Throw (DPDT) configurations. Electrical ratings for AC circuits cover 120V, 240V, and 440V; DC ratings cover 30V, 125V, and 250V.

Flange and Guide Rod Configurations

The series offers flanges in Cast Iron (CI) or Carbon Steel (CS) with pressure classes of 125# or 150#. Flange sizes include 4", 5", 6", and 8". Guide rods are available in Brass or 303SS, with lengths up to 12 ft.

Key Product Differences

The Series 401 distinguishes itself through specific construction types that define the control logic:

• Type 401-1 (Single Stage): Lower stage has adjustable deadband; upper stage has fixed deadband. Typically used for pump operation and high alarm or shutdown.
• Type 401-2 (Two Stage): Lower stage has adjustable deadband; upper stage has fixed deadband. Used for pump operation with high alarm/shutdown.
• Type 401-3 (Two Stage): Upper stage has adjustable deadband; lower stage has fixed deadband. Used for pump operation and low alarm or shutdown.
• Type 401-4 (Two Stage): Each stage has a fixed deadband with an adjustable deadband between stages. Typically used for high/low alarms or shutdowns, including high-high or low-low scenarios.

Circuit specifications vary by switch type and action. Mercury contact switches are identified by codes starting with 48 (e.g., -4820), while snap action contacts use codes such as 78XX for standard applications and 98XX for high-capacity DC applications requiring heat fins if process temperature exceeds 350°F.