• 9366 Deerwood Lane N Maple Grove
  • 763-425-7890 / 800-328-2350
  • sales@pfcequip.com

Walchem’s WEL Series electrodes

Cost-effective differential pH and ORP electrodes for industrial applications. They are modular in design with a rugged CPVC housing that contains the electronics; pH and ORP cartridges can easily be connected or replaced in minutes without tools.

Differential preamp HF Resistant
Universal mounting, easy to install Low Ionic Strength pH cartridge
Easily replaceable electrode cartridges Resistant to electronic noise, ground loops
Electronics are not discarded with the electrode CE Performance & Safety Certifications
Optional ATC Measurement Performance
Cartridge Styles: Range 0 to 14 pH (0 to 12 without sodium ion error) ±1999 mV (ORP)
Flat Surface Response 95% in less than 5 seconds
Bulb / Rod Temperature Range with preamplifier 32 to 158ºF (0 to 70ºC)
Pressure Limit 100 psi without preamplifier 32 to 212ºF (0 to 100ºC)
walchem sensors

Walchem’s amperometric disinfection sensors

offer a cost effective and reliable solution to your disinfection control requirements. Compatible with the WDIS and WebMaster® series controllers, the sensors continuously and directly measure the chemical concentration, without the use of reagents.

We offer sensors, in varying ranges of concentration, for free chlorine/bromine, total chlorine, chlorine dioxide, ozone, peracetic acid and hydrogen peroxide. Whether the application is a cooling tower, food and beverage, drinking water, wastewater, or swimming pool, these sensors are the ideal solution.

  • Low maintenance – no costly reagents or tubing to replace
  • Broad range of applications – wide variety of oxidizers and measurement ranges
  • Fast response – continuous measurement technique
  • No waste – the sample can be returned to the process
walchem sensors

Walchem Non-Membrane Chlorine and Chlorine Dioxide Sensors

  • Designed for higher pressure and temperature, clean water applications
  • Free Chlorine and ClO2 sensors
  • Amperometric 3-electrode sensors
  • The measuring and counter electrodes are in direct contact with the sample
  • The reference electrode is isolated from the water by an electrolyte-filled housing


  • High pressure sample loops where the water cannot be discharged to open atmosphere

    • Up to 8 bar (117 psi)
    • Hot tubs, cooling towers

  • Disinfection of hot potable water systems as currently required by the new ASHRAE standards

    • Up to 70 °C (158 °F)
    • Hospitals, schools, universities

walchem sensors

Walchem’s WDS Series Sensor

  • Differential pH and ORP sensors are designed for industrial applications to be long-lasting and reliable.
  • Differential measurement technique uses two electrodes, one for the process measurement and the other for the reference measurement.
  • Replaceable salt bridge for long life
  • Field proven differential design
  • Transmits signal 3,000 feet (915 meters)
  • Walchem preamplifier models are compatible with Walchem controllers
  • Conventional preamplifier models are compatible with GLI and Aquametrix (Lisle Metrix) controllers
  • Resistant to ground loop problem

Measurement Performance

  • Pressure Limit 100 psi @ 149°F 0.7 MPa @65°C
  • Temperature 23 to 203°F -5 to 95°C
  • Stability 0.03 pH per day, non-cumulative 2 mV per day, non-cumulative
  • Sensitivity 0.001 pH 0.1 mV
  • Range 0 to 14 pH -2000 to 2000 mV (ORP)
walchem sensors

Boiler Contacting Conductivity Sensors

These cell constant 1.0 sensors are designed for boilers with water up to 10,000 μS/cm and pressures up to 250 PSI, 16.7 atm). These inline sensors are constructed from stainless steel and PEEK.

Performance specifications vary with the type of controller, refer to the controller brochure. Typical boiler temperatures are 0 to 205 °C, 32 to 401 °F.

General Purpose Contacting Conductivity Sensors (for W100 Series)

These passive sensors are available in a variety of cell constants for use in conductivities up to 300,000 μS/cm. Typical applications include RO systems and boiler condensate monitoring. They may be mounted inline or submersion, using either polypropylene (0-100 °C, 100 PSI) or stainless steel (0-120 °C, 200 PSI) ½” NPT mounting fittings.

walchem sensors

Walchem Contacting conductivity sensors

Measure conductivity of a solution via electrodes. They are ideal for use in cooling towers and boilers, reverse osmosis equipment, and other non-oily applications. A variety of cell constants are available to handle a range of conductivities. They are available in several different configurations:

Cooling Tower Contacting Conductivity Sensors

Contacting ConductivityThese cell constant 1.0 sensors are designed for cooling towers with water up to 30,000 μS/cm. Lower pressure (up to 150 PSI, 10 atm) polypropylene sensors are available with graphite or stainless steel electrodes, and may be installed inline or submersion. High pressure (up to 300 PSI, 20 atm) inline sensors are constructed from stainless steel and PEEK.

WebMaster controllers require active sensors.

These sensors contain electronics to convert the sensor signal to a voltage that these controllers can read. W400 series controllers use passive sensors that have cables dressed specifically for them. W100 series controller’s passive sensors are dressed differently.

Performance specifications vary with the type of controller, refer to the controller brochure. Typical cooling tower temperatures are 0 to 70 °C, 32 to 158 °F.

walchem sensor

Walchem High Temp & Pressure PH / ORP Sensor

  • Booted BNC, waterproof cable
  • High operating pressure
  • Steam sterilizable
  • Higher temperature rating


  • 102964 Gland, stainless steel, high pressure, ORP
  • 102963 Electrode, ORP, high temperature – high pressure, 10 ft. cable
  • 102029 Electrode, pH, high temperature – high pressure, 10 ft. cable
  • 102028 Gland, stainless steel, high pressure, in-line, pH & ORP
  • 102027 Gland, stainless steel, high temperature – low pressure, pH & ORP
walchem sensor

Walchem Electrodeless Conductivity Sensors

ECond SensorsElectrodeless conductivity sensors measure conductivity of a solution utilizing encapsulated, non-contacting, toroidal technology.

They may be installed in a variety of very harsh chemical control applications, including oily cleaner baths, chromates, rinse tanks, fume scrubbers and other concentrated chemicals up to a conductivity of 1000 mS/cm. The non-contacting, toroidal sensor technology is immune to thin coatings and the contamination and calibration problems that direct contacting sensors are prone to.

CPVC or PEEK construction
In-line or submersion
W400 and WebMaster controllers require active sensors. These sensors contain electronics to convert the sensor signal to a voltage that these controller can read. Each sensor is specific for the range of conductivity that it can detect.

Measurement Performance for Active Sensors:

  • Temperature Accuracy: ± 1% of Reading
  • Temperature Resolution: 1 ° (C or F)
  • Temperature Range: -5 to 80 °C, 20 to 180 °F (CPVC) -5 to 88 °C, 20 to 190 °F (PEEK)
  • Conductivity Accuracy: ± 1% of Span within the specified range
  • Conductivity Resolution: 1 μS/cm, 1 μS/cm, 0.1 mS/cm, 1 mS/cm
  • Conductivity Ranges: 100–1000 μS/cm, 1000–10,000 μS/cm, 10–100 mS/cm , 100–1000 mS/cm

W100 controllers require passive sensors. A single sensor functions over the entire range of conductivity (500 – 2,000,000 μS/cm), and the range is selected in the controller’s software.

Measurement Performance for Passive Sensors:

  • Temperature Accuracy: ± 1% of Reading
  • Temperature Resolution: 1 ° (C or F)
  • Temperature Range: 0 to 70 °C, 32 to 158 °F (CPVC) 0 to 88 °C, 32 to 190 °F (PEEK)
  • Conductivity Accuracy: ± 1% of Span within the specified range
  • Conductivity Resolution: 1 μS/cm, 1 μS/cm, 10 μS/cm , 10 μS/cm and 100 μS/cm
  • Conductivity Ranges: 500–12,000 μS/cm, 3,000–40,000 μS/cm, 10,000–150,000 μS/cm, 50,000–500,000 μS/cm, and 200,000–2,000,000 μS/cm
CPVC Material Sensor
PEEK Material Sensor

Walchem copper and nickel sensors

Optoelectronic devices that are used in conjunction with Walchem’s on-line analyzers in a variety of applications including electroless copper or nickel baths, microetch baths and a number of other chemistries that contain more than 0.10 grams/liter (g/L) of copper or nickel ions.

Flow-through sensors are available for out-of-tank monitoring of solutions, and immersible sensors (copper only) are available for direct in-tank monitoring.

Measurement Performance – Cu

  • Copper Concentration Accuracy ±0.01 g/L (0.001 oz/gal)
  • Copper Concentration Resolution 0.001 g/L (0.0001 oz/gal)
  • Microetch Copper Concentration Range 0.1 – 99 g/L (0.01 – 13.2 oz/gal)
  • Electroless Copper Concentration Range 0.1 – 5.5 g/L (0.01 – 0.73 oz/gal)

**Note: The measurement range is the range of settings in the controller. Many factors in the chemical
composition affect the absorbance, so Walchem cannot guarantee that every copper solution in this
range can be measured

Measurement Performance – Ni

  • Electroless Nickel Concentration Range 0.1 – 25 g/L (0.01 – 3.32 oz/gal)
  • Nickel Concentration Resolution 0.001 g/L (0.0001 oz/gal)
  • Nickel Concentration Accuracy ±0.01 g/L (0.001 oz/gal)
  • Optional pH Input Range 0 – 14 pH
  • Optional pH Resolution 0.01 pH
  • Optional pH Accuracy Electrode and calibration dependent
  • Optional pH Automatic Temperature Compensation Pt100 or Pt1000
  • Temperature Range 0-100°C (32-212°F)
  • Temperature Accuracy ±0.1°C (±0.18°F)
  • Temperature Resolution 0.05°C (0.09°F)
walchem sensor

Walchem Accessories

Walchem Handheld Little Dipper Fluorometer

Handheld Little DipperThe Handheld Little Dipper is a small, lightweight, highly durable handheld fluorometer ideal for quick measurements in the field. Two versions are available for both cooling tower and boiler system applications. Simple to operate, the Handheld Little Dipper is a perfect tool for system verification.

  • Dustproof, watertight, highly durable case
  • Small size easily fits in shirt or jacket pocket
  • Operates using AA batteries for >10,000 measurements per set
  • Single-point (100 ppb) calibration
  • 5 second warm up
  • Low maintenance field fluorometer

Walchem Little Dipper 2

If your water treatment chemical supplier can provide inhibitor with PTSA or Fluorescein fluorescent dye in the formulation, the Little Dipper 2 makes it easy for our WebMaster to measure and control the Little Dipper 2 concentration!

Turner Designs’ Little Dipper 2 is an accurate, single channel, light industrial fluorometer which installs directly into process streams. It provides an analog signal output proportional to the concentration of the fluorophore being measured. The Little Dipper 2 is a rugged, 24/7 sampling device that provides maximum performance, minimal maintenance, and solid state reliability.

  • Simple calibration with the Web Master ONE
  • Simple installation – now with built-in isolator
  • Provides better control of treatment chemicals
  • Solid-state LED/Photodiode technology, no moving parts
  • Typical sensitivity to less than 1 ppb
  • Quick-disconnect watertight connector
  • Improved turbidity and dissolved iron rejection

Walchem WFM Flowmeters

Utilize the multi-jet principle to provide dependable, accurate performance. They are available in ¾, 1, 1½ and 2” NPT pipe sizes. A pulse output provides a signal to a controller or to a metering pump for proportional chemical feed. A two-wire reed switch or three-wire Hall effect sensor may be specified.


  • WFM071 Water Meter Contactor, ¾”
  • WFM101 Water Meter Contactor, 1″
  • WFM151 Water Meter Contactor, 1½”
  • WFM201 Water Meter Contactor, 2″

Walchem Paddle Wheel

Impeller-type insertion meters designed for use in pipe sizes from ½” to 6”.

High quality jewel bearings provide accurate performance across the entire flow range.

Hall effect sensor output can be connected directly to your controller or metering pump.

  • WFP050 ½” Mounting Tee
  • WFP075 ¾” Mounting Tee
  • WFP100 1″ Mounting Tee
  • WFP150 1½” Mounting Tee
  • WFP200 2″ Mounting Tee
  • WFP300 3″ Saddle
  • WFP600 6″ Saddle
  • WFP400 4″ Saddle

Walchem Epoxy Encapsulated Solenoid for Cooling Towers & boilers

Normally Closed Operation
May Be Mounted In Any Position
1/2”, 3/4” and 1” Sizes


  • 102014 Solenoid Valve, Cooling Tower, 1/2”, 120V
  • 102013 Solenoid Valve, Cooling Tower, 3/4”, 120V
  • 102012 Solenoid Valve, Cooling Tower, 1”, 120V
  • 102219 Solenoid Valve, Boiler, 1/2”, 100-300 PSI, 120V
  • 102220 Solenoid Valve, Boiler, 3/4”, 100-300 PSI, 120V
  • 102571 Solenoid Valve, Boiler, 1/2”, 0-100 PSI, 120V
  • 102572 Solenoid Valve, Boiler, 3/4”, 0-100 PSI, 120V

Walchem preamp for ORP & PH

What do you do when your favorite pH/ORP electrode isn’t available with a built-in preamplifier, but you need to send the signal a few hundred feet? Hook up to this external preamp and you can go 1000 feet if necessary! Compatible with all of Walchem’s controllers.

NEMA 4X, epoxy coated, die-cast aluminum wall mount enclosure

Boost signal for reliable transmission up to 1,000 ft via 22 awg wire

No temperature simulation resistor required when used with Walchem controllers

Walchem Point Level sensors for Webmaster or Webalert

Provide simple low tank level input for controllers and solenoid metering pumps. They are used to stop your metering pump when chemical level is low or for direct input to your Walchem WebMaster or WebAlert for remote low level indication.

190964-3 Switch with 3′ Tube
190964-5 Switch with 5′ Tube

Walchem The motorized ball valve for Boilers

Delivers a torque of 150 in-lbs using a non-reversing motor, opening the valve in 5 seconds and minimizing pressure hammer. The motor is protected in a NEMA 4X enclosure and features an integral thermal overload protector with automatic reset. Repair kits are available as well.

Walchem’s boiler flow control four-V port globe valves

Are equipped with a micrometer dial and pointer which enables the valve to set within 1/100th of a turn of the handwheel. This allows you to fine tune the blowdown flow rate. In the event that the valve becomes clogged, it may be opened to allow the debris to pass, and then returned to the original position.

Walchem Orifice Unions

Offer back pressure and flow control, limited by the available orifice sizes. Each union is supplied with four plates