Mercoid Series 251/253/254

Welded Chamber Level Control — High-Pressure External Mount

Pressure to 1250 psig (86 bar) — Temperature to 750°F (400°C)

The Mercoid Series 251/253/254 is a welded chamber level control for the most demanding high-pressure, high-temperature applications. The heavy-duty welded carbon steel chamber handles pressures to 1250 psig (86 bar) and temperatures to 750°F (400°C), with 400°F (205°C) at the electrical head assembly. The external magnet design reduces the possibility of magnetic particle build-up inside the armature tube. Hermetically sealed switches and explosion-proof housings are available for hazardous locations. The welded construction and external mount design make it ideal for boilers, steam drums, and high-pressure process vessels. The 253 and 254 variants offer flanged process connections for higher-integrity installations.

Request a Quote Contact Us

Specifications

Service

Compatible liquids.

Wetted Materials

Body: carbon steel, optional 316 SS; Float and Trim: 303/304/316/430 SS.

Temperature Limit

Process: 750°F (399°C). Heat fins required above 500°F (mercury), 400°F (snap), 350°F (hermetic snap).

Pressure Limit

1250 psig (86 bar) at 100°F; 1000 psig (69 bar) at 750°F. Higher ratings available.

Enclosure Rating

NEMA 4X standard. Optional explosion-proof housings.

Repeatability

±1/4″ (6.4 mm).

Switch Type

Hermetically sealed snap switch or mercury switch. Optional DPDT or two stage.

Electrical Rating (Hermetic Snap)

5A @ 125 VAC, 5A @ 240 VAC, 5A @ 30 VDC resistive.

Electrical Rating (Mercury)

4A @ 120 VAC/DC, 2A @ 240 VAC/DC. Higher ratings available.

Electrical Connections

Screw terminal.

Conduit Connection

3/4″ female NPT.

Process Connections

251: 1″ female NPT and 1″ socket weld hub; 253: 1-1/2″ 600 lb ANSI flange; 254: 1-1/2″ 900 lb ANSI flange.

Set Point Adjustment

±1″ (25.4 mm).

Mounting Orientation

Vertical.

Specific Gravity

0.6 minimum.

Weight

251: 35 lb (15.9 kg); 253: 42 lb (19 kg); 254: 50 lb (22.7 kg).

Agency Approvals

UL and CSA.

Popular Models

Model Number	Description
251-WT-7810-C1-60	Welded chamber level control, high-pressure, SPDT hermetic snap switch.
253-WT-7810-C1-60	Welded chamber, 1-1/2″ 600 lb ANSI flange, hermetic snap switch.
254-WT-7810-C1-60	Welded chamber, 1-1/2″ 900 lb ANSI flange, hermetic snap switch.

Ready to order or need more information?

Contact our team for pricing, availability, and application support.

Request a Quote