YOKOGAWA SC42-SP34 Conductivity Sensor – 2-Electrode Plug-In Conductivity Cell (Cell Constant 0.01 cm⁻¹, Pt1000)

Product Information

Manufacturer	YOKOGAWA (Yokogawa Europe – label reads “Made in the Netherlands”)
Model	SC42-SP34
Product Type	Contacting conductivity sensor / plug-in conductivity cell (2-electrode)
Product Family	Yokogawa SC42 series – pure water / low conductivity sensors
Cell Constant	0.01 cm⁻¹ (per Yokogawa model code; exact calibrated value is on each sensor’s certificate)
Temperature Element	Pt1000 (built in)
Material	Stainless steel AISI 316L body and electrodes, PEEK insulation
Serial Number	Partly visible on label (starts “UD-06…”); full number not clearly visible in the supplied photograph
Condition	Brand New
Category	Accessories – Marine Sensors & Instrumentation
Supplier	SM MARINE SERVICE™, Chattogram, Bangladesh

Product Introduction

The YOKOGAWA SC42-SP34 is a high-quality stainless steel, 2-electrode contacting conductivity sensor designed for measuring very low conductivity in pure water, condensate and boiler feed water. With a cell constant of 0.01 cm⁻¹ and a built-in Pt1000 temperature element for automatic temperature compensation, it gives stable and accurate readings in ultra-pure and high-purity water systems.

SM MARINE SERVICE™ (https://www.smmarineservice.com/) supplies brand new Yokogawa SC42-SP34 conductivity sensors to ship owners, ship managers, power plants and industrial customers worldwide. The units shown in our photographs are new sensors with protective yellow net sleeves, including versions with connection cable fitted.

What Is This Equipment?

A conductivity sensor (conductivity cell) measures how well water conducts electricity. Pure water conducts very poorly; when salts, chemicals or seawater leak into the water, conductivity rises. The SC42-SP34 sends a raw conductivity signal and a Pt1000 temperature signal to a Yokogawa conductivity analyzer/transmitter, which shows the value in µS/cm and can give alarms.

In the Yokogawa model code, SC42 = conductivity sensor family, S = stainless steel 316L, P = plug-in type with plug-socket connector (no ID-chip), 3 = cell constant 0.01 cm⁻¹, and 4 = 2-electrode flow-cell type.

Main Features

• 2-electrode contacting conductivity measurement for pure and ultra-pure water
• Cell constant 0.01 cm⁻¹ – pre-calibrated by the manufacturer
• Built-in Pt1000 temperature element for temperature compensation
• Robust AISI 316L stainless steel body and electrodes with PEEK insulation
• Plug-socket connector with gold-plated contacts – quick sensor replacement
• Rated up to 150 °C and 10 bar (142 PSIG)
• Intrinsically safe approvals (ATEX/IECEx, FM, NEPSI) for the plug-socket version
• Large-bore design for flow fittings (FF40 / FS40 / FD40 holders)

Yokogawa SC42-SP34 conductivity sensor – nameplate showing model SC42-SP34, Made in the Netherlands

Main Technical Specifications

Measuring principle	2-electrode contacting conductivity
Cell constant	0.01 cm⁻¹
Typical measuring range	Approx. 0.02 to 2,000 µS/cm (depends on analyzer)
Electrodes / body	Stainless steel AISI 316L
Insulation	PEEK
O-ring	FKM (Viton)
Temperature element	Pt1000 (IEC 751)
Process temperature	0 to 150 °C (32 to 302 °F)
Process pressure	0 to 10 bar g (0 to 142 PSIG)
Connection	Plug-socket connector, gold-plated contacts
Ingress protection	IP65 (with connector fitted)
Mounting	Plug-in into flow fitting / holder (FF40, FS40, FD40)
Hazardous area	ATEX / IECEx Ex ia IIC T3…T6 Ga, FM Class I Div 1, NEPSI
Weight (package)	Approx. 0.65 kg
Country of manufacture	The Netherlands (as printed on label)

Specifications are from Yokogawa’s published general specifications for the SC42 series; please confirm against your installed system before ordering.

Inside the Unit: PCBs, Modules & Part Numbers

The SC42-SP34 is a passive sensor – it has no PCB, circuit board or electronic card inside. It contains only the measuring electrodes, the Pt1000 temperature element and the plug-socket connector. All electronics are in the connected Yokogawa conductivity analyzer/transmitter. Related part numbers that customers often search together with this sensor:

K1500AG – O-ring set (Viton)

Viton O-rings 29.74 × 3.53 mm (pack of 5) for sealing the sensor in its fitting.

K1500AH / K1500AK / K1500FX – Alternative O-rings

FFKM, EPDM and silicone O-ring options for different process media.

K1500HE – O-ring set for FS40-S23 fitting

Silicone O-ring set for the FS40-S23 flow fitting subassembly.

K1522PS – Protection sleeve

Protection sleeve for 3/4" NPT sensor versions.

WU40 – Sensor cable

Yokogawa sensor cable used with SC42 plug-in sensors (cable length/suffix: Not verified for the units shown).

Main Components & Related Units

• Analyzers / transmitters: Yokogawa FLXA21, FLXA202, SC202S (named in Yokogawa SC42 documentation); compatibility with older EXA SC450 / SC402 analyzers – Not verified
• Flow fittings / holders: FF40, FS40 (e.g. FS40-S23), FD40
• Junction boxes: BA10, BA11
• Extension cables: WU40, WU10, WE10, WF10
• Related sensor models: SC42-SP24, SC42-SP14, SC42-SP04, SC4A, SC41-SP34 (older equivalent)

Marine & Industrial Applications

• Ship auxiliary boiler feed water and condensate conductivity / salinity monitoring
• Detection of seawater leakage into condensate systems
• Fresh water generator and distilled water quality monitoring
• Steam turbine and power plant condensate polishing
• Reverse osmosis (RO) and demineralizer outlet water
• Pharmaceutical, semiconductor and high-purity water systems

Close-up of a brand new Yokogawa SC42-SP34 conductivity cell with plug-socket cable connector

Common Problems & Troubleshooting

• Unstable or drifting reading: check for air bubbles in the flow fitting and make sure the sensor is fully immersed.
• Reading too low: electrodes may be fouled or coated – clean as described by Yokogawa and re-check calibration.
• Wrong temperature value: measure the Pt1000 resistance (about 1000 Ω at 0 °C, about 1078 Ω at 20 °C).
• No reading / open circuit: inspect the plug-socket connector, cable and terminals for moisture or damage.
• Wrong value after replacement: enter the correct cell constant from the new sensor’s certificate into the analyzer.

Safety note: isolate and depressurise the line and allow it to cool before removing the sensor. In hazardous areas follow the intrinsic safety rules and certificates.

Common Alarms

Alarm messages are generated by the connected analyzer (not by the sensor). Please refer to your analyzer’s manual for its specific alarm and error codes.

Maintenance Tips

• Inspect and clean the electrodes at regular intervals.
• Replace O-rings (e.g. K1500AG) whenever the sensor is removed.
• Keep the connector dry and clean; fit the protective cap when disconnected.
• Store spare sensors at -30 to 50 °C in their original packing.
• Verify calibration against a reference instrument periodically.

Spare Parts & Replacement Availability

SM MARINE SERVICE™ supplies the Yokogawa SC42-SP34 and related conductivity sensors and accessories. For a fast quotation please send: model number, nameplate photo, required quantity, cable requirement, vessel name / IMO (if marine) and delivery port. We arrange worldwide shipping to ships and ports.

Why This Equipment Is Still Used

The SC42 series is widely installed in boiler, condensate and pure water systems. Its rugged 316L construction, high temperature rating and simple plug-in replacement make it a trusted choice, and an exact replacement avoids changing fittings, cables or analyzer settings.

FAQ

Q1. What is the Yokogawa SC42-SP34?
A 2-electrode stainless steel plug-in conductivity sensor with cell constant 0.01 cm⁻¹ and Pt1000.

Q2. What does SP34 mean?
S = stainless steel, P = plug-in connector, 3 = cell constant 0.01 cm⁻¹, 4 = 2-electrode flow type.

Q3. Does the SC42-SP34 contain a PCB?
No. It is a passive sensor; the electronics are in the analyzer.

Q4. Which analyzers work with it?
Yokogawa FLXA21, FLXA202 and SC202S are named in Yokogawa documentation. Other analyzers – please ask us.

Q5. What is the maximum temperature and pressure?
150 °C and 10 bar (142 PSIG).

Q6. Which temperature element is inside?
Pt1000.

Q7. Can it be used for boiler feed water on ships?
Yes, it is suitable for low-conductivity condensate and feed water monitoring.

Q8. Which holder does it need?
FF40, FS40 or FD40 flow fittings.

Q9. What is the O-ring part number?
K1500AG (Viton, 29.74 × 3.53, pack of 5); alternatives K1500AH, K1500AK, K1500FX.

Q10. Is your SC42-SP34 new?
The units shown are brand new; please confirm current availability with us.

Q11. Do you ship worldwide?
Yes, SM MARINE SERVICE™ ships worldwide to vessels and ports.

Short Product Description

The YOKOGAWA SC42-SP34 is a brand new 2-electrode plug-in conductivity sensor made in the Netherlands, with a cell constant of 0.01 cm⁻¹, a built-in Pt1000 temperature element and an AISI 316L stainless steel body with PEEK insulation. Rated up to 150 °C and 10 bar, it is used for pure water, boiler feed water, condensate, fresh water generator and RO water conductivity monitoring on ships, power plants and industrial plants. It connects to Yokogawa conductivity analyzers such as the FLXA21/FLXA202 and fits FF40/FS40/FD40 flow holders. SM MARINE SERVICE™ supplies this sensor with worldwide shipping and technical support.

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SM MARINE SERVICE™ – Marine Automation & Navigation Equipment Supplier

Available Equipment Conditions: New • Used • Refurbished • Reconditioned (Specific product condition and availability are subject to confirmation.)

Stock Locations: Bangladesh • China

Services: Worldwide Shipping • Technical Support • Spare Parts Supply • Marine Equipment Sourcing

Samir Market, DT Road, Pahartali, beside CDA Market, Chattogram, Bangladesh

Mobile / WhatsApp / Viber: +88 01818 929292

Email: info@smmarineservice.com

Website: https://www.smmarineservice.com/

Contact SM MARINE SERVICE™ today with your model number and nameplate photo for a quick quotation on the Yokogawa SC42-SP34 conductivity sensor.

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