Through Wall Reference Electrodes

data Through-wall reference electrodes are used for measuring corrosion potential on the inside of condenser waterboxes, circulating pipes, tanks and vessels. These electrodes are installed by threading into a tapped hole on the wall; a junction box is typically attached to the other end to protect the wiring connections. Through-wall reference electrodes can be ordered with any of the sensing elements listed in the adjacent sidebar.

The Standard Probe (Model FS) uses a CPVC extension tube and a inch NPS PVC nipple for attachment. It can be used at pressures up to 40 psi (270 kPa) and intermittent temperatures up to 180F (82C). The Heavy Duty Probe (Model FH) has a glass reinforced epoxy (G-10 GRE) extension tube and a 316L stainless steel nipple. It can be used at pressures up to 75 psi (0.5 MPa) and intermittent temperatures up to 210F (98C). Model FH is available in three size variations:  Model FH10 is threaded into a 1 inch NPT hole, Model FH7 is threaded into a 3/4 inch NPT hole, Model FH5 is threaded into a 1/2 inch NPT hole; all three variations have a 1 inch NPT thread on the termination side. 

The temperature limits stated are those for the wetted materials of construction. Through-wall reference electrodes should generally not be continuously used at temperatures exceeding 110F (45C) because the reference potential will be significantly different from its value at ambient temperature and the electrode service life will be drastically shortened. The product will survive occasional brief temperature excursions up to the limits stated in the preceding paragraph. For applications involving continuous exposure to temperatures over 110F (45C), our Process Vessel Reference Electrode is recommended.

The design life of a reference electrode is an estimate of the time based on test results it would take for enough salt to diffuse out from the inner core to lower the salt concentration to below saturation. At EDI, we use several techniques to extend this time as much as possible. One of these techniques is to increase the amount of salt reserve contained in the gel. This is one reason why longer life electrodes have physically bigger housings. Download our paper Factors Affecting the Accuracy of Reference Electrodes to learn more.


Complete Product Information is available for downloading as pdf files. Click on the link below to download.
Standard Probe (Model FS ).
Heavy Duty Probe (Model FH ).