Cognesense - Measure, Monitor, Protect

664, 666 & 668 (F)

For terminal operators, refinery and chemical engineers, boiler and heater treater operators, water and wastewater utilities, and EPC specifiers who need high-integrity point-level control on pressurized vessels or bypass chambers, the Omnitrol 664F / 666F / 668F delivers rugged flanged chamber construction, factory specific-gravity calibration, and predictable switching differentials across a wide range of process fluids.

Unlike float switches or capacitance probes that can foul, drift, or require frequent field adjustment, the 66xF family uses displacer-based magnetic switching inside a forged flanged chamber that is hydrostatically tested to 1.5× its rated pressure. Each unit is tuned at the factory to the process liquid density, providing accurate alarm actuation with no field calibration required.

This design makes the series ideal for API 2350 overfill protection, separator service, heater treaters, steam systems, and pressurized tank bypass chambers, ensuring safe isolation, long service life, and reliable switching in critical industrial environments.

664, 666 & 668 (F) Flanged Chamber Mounted Controls

Details

The Omnitrol 664F / 666F / 668F provides single-point mechanical level switching using a displacer and magnetic snap-action mechanism housed within a pressure-rated flanged chamber.

Each unit is factory-set to the liquid’s specific gravity, ensuring predictable actuation without field calibration.

The compact flanged chamber design enables straightforward installation on:

Pressurized vessels
External bypass columns
Separator chambers
Interface vessels

The switch head can also be serviced without entering the vessel, reducing maintenance downtime and improving safety.

With UL and CSA approvals, compatibility with ANSI 150–1000 lb flanges, and ratings up to 1000 psig at 500 °F, the 66xF series is designed for demanding refinery and industrial service.

Applications

High-Pressure Alarm Protection: The flanged chamber design safely handles pressures up to 1000 psig at 500 °F, providing dependable alarms for heater treaters, steam drums, and high-pressure vessels.
Tight Alarm Bands for Light Products: Models such as the 666F and 668F offer small, predictable switching differentials at low specific gravities, ensuring stable control and minimizing false alarms with light hydrocarbons.
Pressurized Tanks with Bypass Chambers: The external chamber isolates the sensing element, allowing the switch head to be serviced without opening the vessel or compromising pressure integrity.

Technical Specifications

Parameter

Specification

Models

664F (4″ chamber), 666F (6″ chamber), 668F (8″ chamber)

Technology

Mechanical displacer with magnetic snap-action switching

Chamber Style

Flanged external bypass chamber

Pressure / Temperature

Up to 1000 psig at 500 °F (depending on configuration)

Specific Gravity

Maximum SG 1.7, factory calibrated

Displacer

Graphite standard (other materials optional)

Process Connections

ANSI 150 / 300 / 600 / 1000 lb flanges (model dependent)

Enclosures

Weather-resistant, explosion-proof, vapor-proof, rain-tight

Hazardous Area Ratings

UL / CSA Class I Groups B-D; Class II Groups E-G

Switch Options

SPDT or DPDT microswitches with field wiring terminals

Mounting

Side chamber bypass or pressurized vessel ports

Certifications

UL and CSA approved

2026 COST ESTIMATE

Support

If you have a question not covered here, please contact support for assistance.

Do these switches require field calibration?

−

No — they are factory calibrated to your liquid’s specific gravity.

Can this model handle high-pressure and high-temperature service?

Yes — up to 1000 psig and 500 °F, depending on configuration.

Why is the flanged design beneficial for high-pressure applications?

The flanged design provides a highly robust, secure, and easily verifiable pressure seal that meets standard plant piping specifications. This is critical in high-pressure applications where integrity is paramount, and it simplifies the process for maintenance isolation using standard spool piece removal.

What is the significance of the hydrostatic proof test?

⁠The hydrostatic proof test verifies the physical integrity of the welded chamber by subjecting it to 1.5 times the maximum rated pressure before it leaves the factory. This provides an extra layer of quality assurance and regulatory compliance, confirming the vessel integrity for high-pressure service.

Can I service the switch without opening the vessel?

⁠Yes — the external chamber design allows head removal without tank entry.

What applications benefit most from the 66xF design?

Pressurized vessels, heater treaters, bypass chambers, separators, boilers, API 2350 overfill points.

When should I select the 666F or 668F over the 664F?

Pressurized vessels, heater treaters, bypass chambers, separators, boilers, API 2350 overfill points.

When should I choose the 66xC or 66xW versions instead?

66xC for compact NPT-connected short chambers
66xW for long welded chambers or custom nozzle spacing
76x series for dual setpoints