Series-221-223-224Configuration

Supported Applications

The Dwyer Series 221, 223, and 224 are magnetic liquid level controls designed for heavy-duty industrial environments. These flanged chamber switches feature a removable float to facilitate inspection and maintenance without removing the entire assembly from service. Documented applications include oil refineries, chemical plants, power generating stations, pumping stations, heat transfer systems, sanitary/waste water facilities, drip legs, hydraulic systems, and boilers.

Operating Conditions & Performance

The series operates via mutual magnetic attraction between a plunger on the float and a magnet on the switch assembly. The switch actuates when the float reaches the operating point and returns to its original position by gravity as the level drops. Repeatability is specified at ±1/4" (6.4 mm).

Performance ratings vary by construction code, specific gravity, and temperature:

• C1-60 Construction: Rated for 600 psig (41 bar) at 100°F (38°C), reducing to 550 psig (38 bar) at 475°F (246°C). Requires a minimum specific gravity of 0.6.
• C1-75 Construction: Rated for 1000 psig (69 bar) at 100°F (38°C), reducing to 850 psig (59 bar) at 475°F (246°C). Requires a minimum specific gravity of 0.75.

Process temperature ranges up to 475°F (246°C). Ambient operating temperature is rated to 212°F (100°C).

Variations by Series and Connection Type

• Series 221: Features a flanged carbon steel chamber with standard 1" NPT pipe weld connections. Optional configurations include 1" socket weld hubs or flanges.
• Series 223: Utilizes 1" RF forged steel ANSI specifications for process connections, available in side/bottom or side/side orientations. Flange centerline is 14" (356 mm).
• Series 224: Similar to Series 223 with 1" RF forged steel ANSI flanges but features a longer flange centerline of 14½" (371 mm). Available in side/side process connection configurations.

Configuration Options

The series offers extensive configurability across enclosures, circuit arrangements, and special service options to meet diverse installation requirements.

Enclosure Ratings and Materials

• G (General Purpose): NEMA-1. Housing materials include painted steel and aluminum.
• WT (Weatherproof): NEMA-3R, 4, 4X. Constructed from painted steel, aluminum, and neoprene.
• E (Explosion-proof): NEMA-7, 9; Class I Groups B, C, D; Class II Groups E, F, G. Aluminum housing. CSA approved for Groups C, D, E, F, G only.
• EV (Explosion-proof – Vapor-proof): NEMA-7, 9; Class I Groups B, C, D; Class II Groups E, F, G. Housing includes aluminum and neoprene. CSA approved for Groups C, D, E, F, G only.

Electrical connections vary by enclosure: terminal blocks are provided for G, WT, or E enclosures, while EV enclosures include 18" (460 mm) leads.

Circuit Arrangements and Switch Types

• Mercury Switches: Available in single-stage SPST configurations that close as level falls or rises, SP-DT arrangements where one circuit closes as the other opens, and DP-ST/DP-DT two-switch options.
• Snap-Acting Switches: Offered in single-stage (SPDT) and two-stage (2 SP-DT) configurations. Includes hermetically sealed snap switches (-7810HM/-7806HM).
• High Capacity DC Snap Switches: Single stage (-98XX series) and two stage options available.
• High Temperature Snap Switches: Continuous rating of 800°F (425°C). Note: For C1-60 types, pressure is rated at 350 psig (25 bar); for C1-75 types, pressure is rated at 550 psig (38 bar).

Options and Accessories

• HF: High temperature fins. Recommended if ambient temperatures are extremely high or process temperatures exceed 500°F (260°C) for extended periods.
• H2: Provides a 1" socket weld hub instead of the standard 1" NPT connection, and includes a breather and drain for E type enclosures. Recommended for high humidity or outdoor service.

Wetted Materials

The chamber is constructed from carbon steel. Trim materials include 316SS, 303SS, 304SS, and 430SS stainless steels.

Key Product Differences

Differences between the Series 221, 223, and 224 are primarily defined by their process connection geometry and flange specifications. The Series 221 is distinguished by its standard 1" NPT pipe weld interface with optional socket weld or flanged upgrades. In contrast, Series 223 and 224 are factory-configured with 1" RF forged steel ANSI flanges; the primary dimensional distinction between these two series is the flange centerline measurement (14" for Series 223 versus 14½" for Series 224). All three series share identical pressure/temperature rating envelopes based on their C1-60 or C1-75 construction codes and specific gravity requirements.

Weight varies by model: Series 221 weighs approximately 60 lb (27 kg), Series 223 is 70 lb (32 kg), and Series 224 is 77 lb (35 kg).