CCS 6900G/P pressure switch



CCS 6900G/P Pressure Switch Installation and Troubleshooting Guide

In industrial fluid and pneumatic systems, pressure switches play an important role in pressure protection, alarm interlocking, and sequential control. CCS non explosion proof switches are known for their long lifespan and set point accuracy in harsh environments, and are widely used in situations that require reliable pressure monitoring. The CCS 6900G/6900P series pressure switches adopt an externally adjustable structure, support SPDT or DPDT contact configuration, and provide multiple electrical rating levels. For engineers who are replacing shutdown pressure switches, optimizing existing control systems, or handling on-site faults, understanding their installation specifications, wiring logic, adjustment methods, and common troubleshooting paths is key to ensuring long-term stable operation of the equipment.

Product positioning and electrical specifications

CCS 6900G/6900P pressure switches are non explosion proof pressure control components designed to maintain long lifespan and stable set point accuracy under adverse environmental conditions. The electrical connection is made through built-in free leads or cables, and users need to complete the termination in a suitable junction box or terminal facility. According to different contact configurations, switches are divided into two main forms: SPDT standard and DPDT.

The SPDT standard wiring colors are: RED corresponds to N/C, BROWN corresponds to C, and BLUE corresponds to N/O. Under DPDT configuration, the first group consists of RED N/C 1, BROWN C 1, BLUE N/O 1; The second group consists of BLACK N/C 2, YELLOW C 2, and PURPLE N/O 2. When wiring, it is necessary to check the common terminal, normally closed terminal, and normally open terminal to avoid connecting the load to the wrong contact.

Electrical ratings are divided into multiple levels. The 11 AMP level can withstand 11 A, 1/4 HP, 125/250 VAC, 5 A, 30 VDC, as well as 0.5 A, 125 VDC. The AMP rating is 5 A, 125/250 VAC, and 5 A, 30 VDC. The AMP level is 1 A, 125 VAC and 1 A, 30 VDC, and uses gold contacts, suitable for low-level signal switching. When selecting, the appropriate level should be chosen based on the load type, current size, DC arc extinguishing requirements, and switching frequency. If used for PLC input or low-voltage signal circuits, the gold contact version can reduce oxidation effects and improve contact reliability.

When ordering or replacing, the complete catalog part number should be specified, including optional modifications and factory set points. If specific pressure action values are required on site, it is recommended to indicate the factory set values when ordering to reduce on-site adjustment errors. The nameplate indicates the maximum withstand voltage limit, which must not be exceeded during installation and operation.

Safety preparation before installation

Before installing the pressure switch, all pressure must be released. Whether installing or disassembling, pressurized operation may result in medium ejection, component flying out, or personal injury. At the same time, the pressure resistance limit listed on the nameplate shall not be exceeded. For situations where equipment or personnel are protected from unsafe pressure hazards, installation and operation must be carried out in accordance with applicable specifications, regulations, and standards, and coordinated with system design or procedures to mitigate the risks that may arise from switch failure.

General safety requirements include: complying with all warnings and precautions; Comply with government or other applicable regulations; The built-in free lead or cable should be mechanically protected and terminated in a suitable junction box or terminal facility; If the on-site wiring is located in an explosive environment, certified termination facilities must be used. Non explosion proof switches shall not be used in hazardous areas that require explosion-proof certification. Electrical connections must be completed by qualified electricians, and wiring is strictly prohibited during power on to avoid the risk of electric shock.

Mechanical installation and pipeline connection

The CCS 6900G/6900P pressure switch can be installed in any position, usually fixed on a flat surface, using two mounting holes and M5 screws with a minimum length of 50 mm. The installation surface should be flat and sturdy to avoid deformation of the housing due to vibration or thermal expansion. Most units provide female NPT ports that can be connected to NPT pipe fittings or NPT tapered pipe threads, with a maximum installation torque of 12 ft.lb. It is recommended to use union or bendable tubing to eliminate excessive stress on the shell. All threaded connections should avoid excessive torque, otherwise it may damage the port or housing.

The pipeline sealing compound is superior to Teflon tape, but both are acceptable. Be careful when using to avoid introducing sealing materials into pressure switches or inside pipelines. Sealing debris may block the pressure channel, causing the switch to be unable to sense the actual pressure. After installation, all connections should be checked for leaks and the switch ports should be confirmed to be compatible with the medium. For situations with high vibration, it is recommended to increase vibration reduction measures or use flexible connections.

Electrical connection and grounding

Electrical connections must be made under power-off conditions. Before operation, it is necessary to check whether there is a multi circuit power supply to ensure that all relevant power sources have been isolated. The wiring should comply with NEC and all applicable specifications. The conductor is located within the male conductor connection, and the conduit casing should be tightened with a wrench or subjected to a maximum torque of 12 ft.lb. When wiring, as many wires as possible should be retained as service loops for subsequent maintenance and replacement.

Proper grounding is crucial. Grounding must be completed using the provided grounding wire. Users are responsible for ensuring the effectiveness of ground fault protection and equipotential bonding functions, or adopting other equally effective methods. If the system requires a terminal box kit, corresponding accessories can be optionally provided. For DPDT switches, the two sets of contacts should be wired separately to avoid confusion at the common end. If the load is inductive or capacitive, contact protection and arc extinguishing measures should be considered to extend the electrical life.

Pressure setting and adjustment

The pressure setting of CCS 6900G/6900P pressure switch is externally adjustable, but the factory set model is not suitable for on-site adjustment. Before adjustment, if the electrical circuit cannot be used for testing, the power should be disconnected and a suitable circuit tester or light box should be used to determine the contact status. Release the maintenance cover, insert a screwdriver into the adjustment screw slot, rotate clockwise to increase the set value, and counterclockwise to decrease the set value. After the adjustment is completed, tighten the maintenance cover again, reconnect the circuit, apply a maximum torque of 12 ft.lb, and then restore the power supply.

When adjusting, gradually approach the target value and avoid a large rotation at once. It is recommended to read the action point and reset point after the system pressure stabilizes, and confirm whether the hysteresis meets the requirements. For critical applications, the set values, adjustment dates, and operators should be recorded. If the switch is used for alarm or interlocking, actual pressure verification should be performed after adjustment, rather than relying solely on electrical testing. Multiple verifications can confirm the repeatability accuracy.

Common troubleshooting

1. The switch does not operate. Firstly, confirm whether the system pressure has reached the set point. If the pressure is normal but the switch does not operate, check whether the pressure port is blocked, whether the sensing element is stuck, and whether the adjusting screw is loose or damaged. In terms of electrical aspects, check whether the wiring between the common terminal and the normally open/normally closed terminal is correct, whether the contacts are oxidized, and whether the load is disconnected. For the gold contact version, it is generally reliable under low-level signals, but overloading may cause permanent damage.

2. Switch misoperation. Possible reasons may include system pressure fluctuations, pump start stop impacts, water hammer, vibration, set point too close to working pressure, excessive installation torque causing shell stress, sealing material entering pressure channels, contact bounce, or external electromagnetic interference. Damping should be increased, set points adjusted, installation rigidity improved, or shielded cables used.

3. Port or thread leakage. Check if the NPT threads match, if the sealing compound or Teflon tape is appropriate, and if the installation torque is within 12 ft.lb. Insufficient torque can cause leakage, while excessive torque can damage threads. If using tapered pipe threads, ensure that the engagement length is sufficient.

4. Poor contact of the contacts. Check if the wiring terminals are loose, if the wires are oxidized, and if the contacts are burned due to overload. Confirm that the actual load does not exceed the rated value. For DC loads, special attention should be paid to arc extinguishing capability, and if necessary, freewheeling diodes or RC absorption circuits should be added.

5. Grounding or interference issues. If the system experiences random misoperation, check whether the ground wire is reliably connected, whether the cable is laid in parallel with the power line, and whether the shielding layer is single ended grounded. In a multi circuit system, it should be confirmed that there is no mixing of wires from different circuits.

6. The adjustment is invalid. If there is no change in the set point after rotating the adjustment screw, it may be due to the factory setting being locked, the adjustment mechanism being damaged, or the pressure channel being blocked. At this point, the operation should be stopped and qualified service personnel should be contacted. Do not forcefully rotate to avoid damaging the internal mechanism.

7. DPDT second group contacts are abnormal. Check the BLACK, YELLOW, PURPLE wiring and confirm the second set of common and normally open/closed terminals. If the first group is normal and the second group is abnormal, it may be due to wear and tear of the internal linkage mechanism or wiring errors.

8. Malfunctions caused by the environment. Temperature exceeding the allowable range, corrosive media, humidity, freezing, or mechanical impact may all affect performance. It should be ensured that the switch operates under the specified environmental conditions, and protective covers or isolation devices should be installed if necessary.

Checklist for Replacing Shutdown Pressure Switches

When replacing CCS or other brand pressure switches that have been discontinued, one should not only look at their appearance. The following items should be checked: port type and thread specification, female NPT or male NPT; Pressure range and pressure resistance limit; Set point and adjustable range; Contact form SPDT or DPDT; Electrical ratings, including AC/DC current and horsepower; Do you need gold contacts; Electrical connection method, free lead or conduit; Lead color and quantity; Installation hole spacing and screw specifications; Working temperature; Is explosion-proof certification required; Media compatibility; Vibration and impact requirements.

If the original system is a safety protection circuit, the set points and interlock logic must be rechecked after replacement. If the original switch is set by the factory, the replacement part should also specify the same set point. If the original system uses DPDT to achieve dual circuit control, the replacement parts must keep the two sets of contacts independently available. If the original switch is used for low-level signals, the gold contact version should be selected. After the replacement is completed, leakage testing, electrical testing, and actual pressure action testing should be conducted.

Maintenance and regular verification

Daily maintenance includes checking for leaks, tightening terminals, mechanical protection of cables, grounding continuity, and cleaning of enclosures. After cutting off the power and releasing the pressure, the contact status and adjustment mechanism can be checked. It is recommended to conduct a set point verification at least once a year, which can shorten the cycle for safety critical applications. During verification, calibrated pressure sources and electrical indicators should be used to record the action and reset values. If set point drift, increased contact resistance, or delayed response is found, it should be replaced in a timely manner.

The service can only be performed by qualified personnel. Unauthorized disassembly may affect performance and void warranty. Spare parts should be stored in a dry and clean environment to avoid corrosion and mechanical damage. For switches that have been idle for a long time, they should be checked for flexibility before installation.