CCS 646DZE Adjustable Differential Pressure Switch – Explosion Proof

Overview

The CCS 646DZE Series Adjustable Differential Pressure Switch is a high-performance industrial pressure control device engineered specifically for hazardous area applications. Utilizing the patented CCS Dual-Snap® Belleville disc spring principle, this series provides highly stable, repeatable switching performance even under extreme vibration, shock, and pressure cycling conditions  .

Unlike conventional diaphragm-only switches, the 646DZE integrates aerospace-based engineering principles with a rugged midsize enclosure and hermetically sealed electrical assembly. The result is a pressure switch capable of maintaining long-term calibration stability in demanding oil & gas, offshore, chemical, and industrial environments.

This series is internally adjustable in the field, allowing precise set point configuration without removing the device from service. The switch supports differential pressure ranges from:

0.4 to 1000 PSID

(0.028 to 68.94 bar / 2.76 to 6895 kPa) 

Technical Specifications

Dual-Snap® Belleville Disc Technology

The defining engineering feature of the 646DZE Series is the Dual-Snap® sensing mechanism.

This technology provides:

• Fast snap action switching

• Reduced contact chatter

• High cycle life

• Repeatable actuation points

• Stable deadband control

• Vibration resistance

Compared to traditional diaphragm pressure switches, the Belleville disc mechanism improves mechanical repeatability and increases operational longevity in cyclic systems.

Hazardous Area & Explosion Protection

The 646DZE Series is designed for operation in hazardous environments and offers:

• Explosion-proof hermetically sealed electrical assembly 

• NEMA 4, 7, 9, 13 / IP66 enclosure rating 

• UL / CSA Listed 

• ATEX certification (Option Y) 

• Dual Seal ANSI/ISA-12.27.01 

• NACE MR0175 / ISO 15156 compliance 

These certifications make the 646DZE suitable for:

• Class I, Div 1 & Div 2 hazardous areas

• Oil & gas production facilities

• Refineries

• Offshore platforms

• Chemical processing plants

• Gas compression systems

Adjustable Set Point Range

The series covers multiple pressure ranges including:

• 1.2–18 PSID

• 6–75 PSID

• 10–75 PSID

• 20–150 PSID

• 50–375 PSID

• 330–1000 PSID 

Deadband varies by range (approx. 0.8 to 80 PSI depending on model)  .

Field setting is performed by opening the access cover and adjusting the internal wheel mechanism. Clockwise increases set point; counterclockwise decreases  .

Electrical Characteristics

Available electrical configurations:

• SPDT

• DPDT

• Double Break

Typical ratings include:

• 15A @ 125/250 VAC

• 15A @ 480 VAC

• 2A @ 28 VDC

• Gold contact options available (-7008 suffix) 

Hermetically sealed assemblies improve reliability in corrosive and high-humidity environments.

Pressure Ratings

Depending on range:

• Max System Pressure: up to 3000 PSIG 

• Proof Pressure: up to 5000 PSIG 

• High over-pressure capability (system & proof) 

This makes the series suitable for high-pressure hydraulic and gas systems.

Wetted Materials

Standard wetted parts include:

• 300 Series Stainless Steel Pressure Port

• Polyimide Diaphragm (Standard)

• Stainless Steel Diaphragm (-7011 option)

• Viton O-Ring 

Optional material suffixes are available for compatibility with various media.

Operating Temperature

Operating temperature range:

-40°F to 186°F (-40°C to 86°C)

(Temperature depends on O-ring selection) 

Industrial Applications

The CCS 646DZE Series is widely used in:

• Differential pressure monitoring across filters

• Pump protection systems

• Compressor monitoring

• Hydraulic safety interlocks

• Gas pressure differential alarms

• Burner management systems

• Offshore drilling equipment

• Refinery process control

• Chemical plant pressure monitoring

• Pipeline safety systems

Ordering Logic

Part numbers follow structured configuration:

Example:

646DZEM1-7011

Series + Electrical Option + Suffix 

Available suffix examples:

• 7008: Gold Contacts

• 7054: 2 Meter Free Leads

• 7065: 18” Teflon Free Leads

• 7108: 1/4”-18 NPT Female High Pressure Port 

Request a Quote for CCS 646DZE Adjustable Differential Pressure Switch – Explosion Proof

For a quotation, model configuration assistance, lead time, and technical consultation regarding the CCS 646DZE Adjustable Differential Pressure Switch Series, contact Seven Star LLC. Our engineering team can assist in selecting the correct pressure range, electrical configuration, and certification option for your hazardous area application.

Selecting the Right 646DZE Model

The most common selection mistake with differential pressure switches is choosing a range where the set point sits at the very edge of the adjustable span. Pick the range so that the required set point falls comfortably within it, which gives better repeatability and room to re-adjust later. Then check that the maximum static line pressure the switch will see is within the system pressure rating of the chosen range, not just the differential.

• Set point and direction: the differential value and whether the switch should act on rising or falling differential.
• Static pressure: the normal and maximum line pressure on both ports.
• Electrical duty: SPDT, DPDT or double break, and whether a low-energy PLC input calls for gold contacts.
• Area classification and certification: the approvals required for the installation location.
• Process medium: sour service or corrosive fluids may drive the NACE option and wetted material choice.

For replacements, the full model number on the switch nameplate defines range, electrical configuration and options, and is the quickest way to order a like-for-like unit.

Installation and Calibration

Mount the switch on a vibration-free support where possible and connect the high and low pressure ports the right way round, as a reversed connection is a frequent cause of a switch that never trips. Use a three- or five-valve manifold so the switch can be isolated, equalised and tested without disturbing the process. Seal conduit entries as required for the hazardous area.

Calibrate on the bench or in place with a calibrator applying differential pressure: approach the set point slowly, note the trip and reset values, and adjust until the trip occurs at the required value. Record the deadband observed, since it determines when the switch resets.

Maintenance and Troubleshooting

• Functionally test trips at the interval set by the site inspection or safety programme.
• Check impulse lines for blockage, trapped gas in liquid service or liquid in gas service.
• If the switch chatters, look for pulsation in the process and consider a snubber.
• Inspect cover seals and conduit sealing after work on the enclosure.

Applications in Oman and the GCC

In regional oil and gas facilities, the 646DZE is used for filter differential alarms, compressor lube oil and seal systems, pump protection and flow confirmation on skids. Its hazardous area approvals and sour-service options make it a good fit for wellhead, gathering and gas compression installations.

Sourcing Through Seven Star LLC

Seven Star LLC supplies CCS pressure and differential pressure switches across Oman and the GCC. Send us the nameplate model number or your process data, and we will confirm the right configuration and lead time.

Related Products

• 16137-225 – Siemens APACS+/QUADLOG I/O BUS B Cable (2.5 M)
• Teledyne B71875 InstaTrace Oxygen Sensor
• Hach 21679-69 DEHA Reagent 1 Powder Pillows
• Liquiline CM442 Multiparameter Transmitter
• ABB AHM550 – Hydrazine Analyzer – Navigator
• ABB-Color analyzer Aztec AW637
• SHINKAWA VM-5K-411512-000-000-111-0/IS0/EX5 Dual Vibration Monitor