Omron PS-3S Electrode Holder — Specs, Variants & How to Order

By Abdullah Zahid
15 min read
Omron PS-3S 3-electrode resin holder for conductive liquid level control in building water tanks and sump pump systems

Omron PS-3S Electrode Holder — Specs, Wiring Overview, and How to Order from Anywhere in the World

If you are specifying or replacing an electrode holder for a conductive liquid level control system — a building water tank, sump pump circuit, or booster pump skid tied to an Omron 61F series controller — the Omron PS-3S is likely already on your drawing. It is a 3-electrode resin holder from the PS-[]S(R)/-31 family, built with a PBT body, rated for -10 to 70°C at atmospheric pressure, and designed to work directly with Omron F03-01 electrode rods and Omron conductive level controllers. The decision that trips most buyers is not whether to use this family, but which variant to order: PS-3S, PS-3SR, PS-31, or something else entirely.

If you have already confirmed the PS-3S is the correct part for your build, check current pricing and availability at LeadTime.ca — we ship worldwide.

Who Should Buy the Omron PS-3S — and Who Shouldn't

The PS-3S is the right electrode holder when your control scheme uses exactly three sensing points — a common reference electrode, a low-level electrode, and a high-level electrode — for standard pump-start and pump-stop logic. It is a compact, cost-effective choice for engineers staying within the Omron conductive level ecosystem.

  • Your application requires 3-point level control (common, low, high) and no additional alarm or interlock electrodes.
  • The level controller in use is an Omron 61F series or equivalent conductive controller that does not require a built-in resistor at the holder (non-R configuration).
  • The liquid is a conductive water-based medium — tap water, wastewater, make-up water — not an oil, solvent, or highly resistive fluid.
  • The operating environment falls within -10 to 70°C at atmospheric pressure, without steam, vacuum, or high-pressure washdown exposure.
  • The electrode rods used are Omron F03-01, purchased separately and cut to the required level setpoints by the installer.
  • Tank-top mechanical access is available and the mounting geometry suits a vertical-hanging electrode arrangement.

If your control scheme needs four or five sensing points, look at the PS-4S or PS-5S. If your controller wiring or noise-immunity design calls for a built-in resistor, the PS-3SR (6.8 kΩ integrated) is the correct variant. For tight mounting spaces where a different mechanical format is needed, consider the PS-31 single-piece model.

On this page:

What the Omron PS-3S Actually Does in a Level Control System

The PS-3S is a passive mechanical component. It does not contain active electronics in the standard non-R form — it is the physical interface between the liquid in the tank and the Omron level controller on the panel. Its PBT resin body mechanically holds three conductive electrode rods in fixed, parallel positions so they hang vertically into the liquid without touching each other or the tank wall. It insulates those rods from one another and from the mounting structure, maintaining the electrical isolation that makes conductive level sensing work.

When liquid rises to touch an electrode, it completes a low-current circuit back to the controller through the conductive medium itself. The controller — typically the 61F series — interprets that completed circuit as a level signal and triggers the appropriate output: starting a pump, stopping a pump, or setting an alarm. The PS-3S simply maintains the integrity of those three signal paths. Insulation resistance is specified at a minimum of 100 MΩ, which defines the baseline electrical quality the holder must maintain to prevent false level detections from leakage between terminals.

This simplicity is what makes PS-3S installations long-lived in normal building water environments. There are no moving parts, no electronics to fail, and no calibration required after initial electrode length adjustment. The R variants — PS-3SR — add a 6.8 kΩ built-in resistor per electrode circuit, which some controllers require for proper operation or noise rejection. The PS-3S without the R suffix does not include that resistor.

Typical System Architecture for PS-3S Installations

The PS-3S sits between the tank and the controller, serving as the physical entry point for level signal wiring into the control panel. Understanding the component chain helps maintenance teams troubleshoot quickly when level faults appear.

  • Omron 61F series conductive level controller (panel-mounted) — provides excitation voltage, interprets electrode circuit continuity, and drives output relays.
  • Low-voltage signal cable (shielded, routed away from power conductors) — runs from panel to tank top.
  • Omron PS-3S electrode holder (tank-top mounted) — mechanically supports and insulates three electrode rod connections, provides the wiring terminal block.
  • Omron F03-01 electrode rods (purchased separately) — hang vertically into the tank at installer-set lengths for common, low-level, and high-level setpoints.
  • Conductive liquid (tap water, wastewater, make-up water) — completes the low-current sensing circuit between common electrode and level electrodes when submerged.

Where the PS-3S Gets Installed: Applications and Deployment Scenarios

Building water supply and drainage systems represent the core application for the PS-3S. In overhead storage tanks and underground cisterns tied to domestic booster pump packages, the three-electrode scheme handles everything a simple level control loop needs: a common reference, a low-level point that starts the fill pump, and a high-level point that stops it. The PBT resin body is appropriate for tap water and treated potable water service at indoor ambient temperatures.

Sump and basement lift station control is another common deployment. In mechanical rooms and basement pits where float switches are prone to fouling, tangling, or mechanical failure in dirty water, a conductive electrode system using the PS-3S offers a no-moving-parts alternative. The three electrodes handle pump-on and pump-off levels with the common electrode at the lowest point.

HVAC make-up water tanks and cooling tower basins also see PS-3S installations where the fluid is treated water within the operating temperature window and the control scheme does not require more than three sensing points. Light industrial process water tanks — rinse tanks, wash stations, and similar — are a secondary fit provided the fluid conductivity is sufficient and chemical compatibility with the PBT resin is confirmed.

The PS-3S is not the right choice when the application requires additional sensing points such as a high-high alarm or an intermediate level interlock. Four or five electrode points require the PS-4S or PS-5S. Non-conductive fluids, oils, aggressive chemicals, or applications requiring hygienic stainless construction fall outside the PS-3S envelope entirely.

Application Typical Deployment
Building potable water tank PS-3S with F03-01 rods on overhead or underground tank; 61F controller drives fill pump between low and high levels
Basement sump pump control PS-3S in sump pit; no-moving-parts alternative to float switch; common at bottom, pump-on and pump-off electrodes above
HVAC make-up water system PS-3S on treated water expansion tank; controls feed valve or pump for cooling system top-up
Cooling tower basin PS-3S monitoring basin level; triggers make-up water valve at low level, closes at high level
Light industrial process water tank PS-3S on rinse or wash tank; simple fill control without mechanical float exposure to dirty water
Retrofit of float-based system Existing float switch removed; PS-3S and 61F controller installed to improve reliability in fouling-prone environments

Omron PS-3S Specifications That Drive Purchase Decisions

Parameter PS-3S Specification
Manufacturer Omron
Model PS-3S
Product Family PS-[]S(R)/-31 electrode holders
Number of Electrodes (Poles) 3 (common, low level, high level)
Compatible Electrode Rods Omron F03-01 (purchased separately)
Body Material Resin (PBT — polybutylene terephthalate)
Insulation Resistance 100 MΩ minimum
Operating Temperature -10 to 70°C (no icing)
Operating Pressure Atmospheric pressure only
Built-in Resistor Not included (standard PS-3S); PS-3SR variant includes 6.8 kΩ resistor

Full technical specifications are available on the product page at LeadTime.ca.

PS-3S vs PS-3SR vs PS-31 vs PS-4S: Which Electrode Holder Do You Need?

Model Number of Electrodes Built-in Resistor Mechanical Format Best For
PS-3S 3 No Standard holder Standard 3-point water level control; controller does not require R version
PS-3SR 3 Yes (6.8 kΩ) Standard holder Same 3-point applications where controller wiring or noise immunity requires built-in resistor
PS-31 3 Refer to datasheet Single-piece compact format Tight mounting spaces or alternative mechanical interface requirements
PS-4S 4 No (standard) Standard holder 4-point control: adds high-high alarm or additional interlock electrode
PS-5S 5 No (standard) Standard holder 5-point control: full alarm and interlock scheme with intermediate level

If your control scheme requires a high-high overflow alarm or an intermediate level point, the PS-3S will not cover it — the PS-4S or PS-5S is the correct choice. For controllers that specifically call out an R-suffix holder in their wiring documentation, order PS-3SR, not PS-3S. Check current availability for the PS-3S and related variants at LeadTime.ca.

Expert Verdict: Is the PS-3S the Right Part for Your Project?

The Omron PS-3S is a well-matched component for engineers, OEMs, and maintenance teams who are already working within the Omron conductive level control ecosystem and need a compact, cost-effective 3-electrode holder for standard building water or sump applications. If your controller is a 61F series, your fluid is conductive water-based, your environment stays between -10 and 70°C at atmospheric pressure, and your control logic needs nothing beyond common, low, and high sensing points, the PS-3S fits cleanly without over-engineering the solution. The 100 MΩ minimum insulation resistance specification and PBT resin construction are appropriate for these everyday water service conditions, and the holder's direct compatibility with F03-01 electrode rods simplifies the bill of materials.

Where the PS-3S has real limits is equally worth stating directly. It is not suitable for non-conductive or aggressive fluids, steam, vacuum, or pressure above atmospheric. It does not belong in hygienic stainless applications, high-temperature process vessels, or any scheme that requires more than three sensing points. For those situations, the PS-4S or PS-5S covers additional electrode counts within the Omron family, the PS-3SR addresses built-in resistor requirements, and the PS-31 offers a different mechanical format for constrained mounting. Outside the Omron ecosystem, comparable electrode holder families from other industrial automation brands exist, but mixing controller and holder ecosystems adds configuration risk — staying Omron-to-Omron simplifies documentation, support, and spare part sourcing over the system's service life.

On the procurement side, the PS-3S is a low-cost accessory relative to the level controller it supports, and it is generally stocked by major industrial distributors serving North America. Lead times can range from same-day to a few weeks depending on the distributor and order quantity — worth confirming before committing to a commissioning schedule. The variant question is the real sourcing risk: ordering PS-3S when your design calls for PS-3SR, or PS-31 when clearances demand the compact format, creates rework that costs far more than the holder itself. A specialist distributor who can verify the variant against your controller model and check real-time Canadian stock adds meaningful value here. View current pricing and stock status for the Omron PS-3S at LeadTime.ca.

For volume pricing, lead time confirmation ahead of a scheduled shutdown, or help verifying the correct variant for your 61F controller, contact the LeadTime.ca team directly — we ship worldwide.

What Engineers Need to Know Before Ordering the PS-3S

Direct model-specific community feedback on the Omron PS-3S is sparse across the forums and distributor Q&A channels that engineers typically consult — Reddit's automation communities, PLCTalk, PLCS.net, MrPLC, and similar. This is not unusual for a passive accessory in a mature product family. The PS-3S does not generate failure reports or configuration debates the way a complex controller or communication module might. What does surface in broader conductive level sensing discussions is worth knowing before the first installation.

In general discussions of electrode-based level sensing, the recurring technical concern is electrode fouling — scale buildup, biofilm, or debris that bridges adjacent electrode rods and produces false level signals. This is a property of the sensing technology and the liquid handled, not a defect in the holder itself. Engineers specifying PS-3S for tanks with hard water or organic contamination should plan periodic electrode inspection intervals and document cleaning procedures at commissioning. A second recurring theme in these broader discussions is electrical noise: low-voltage electrode signals running parallel to power conductors are susceptible to interference, and users consistently note that shielded cable and physical separation from power runs resolves most intermittent false-trip complaints. Neither observation is specific to PS-3S, but both are directly relevant to any installation using this holder.

The ordering mistake that the datasheet and product family structure point to most clearly — and one that a specialist distributor conversation would catch — is the R versus non-R variant decision. The PS-3SR includes a 6.8 kΩ built-in resistor; the PS-3S does not. Some controller configurations and wiring schemes require the resistor version; others do not. Ordering the wrong suffix means the installation does not match the design drawing and may require a return before commissioning can proceed. When community data is thin, that is exactly the kind of question to raise with LeadTime.ca before the purchase order is placed.

Wiring and Installation Overview for the Omron PS-3S

  • Mount the PS-3S at the tank top so the electrode rods hang vertically and freely into the liquid without contacting the tank walls or each other; verify the holder is secure and the orientation is straight before tightening.
  • Install Omron F03-01 electrode rods into the holder and adjust lengths to the required common, low-level, and high-level setpoints; tighten electrode fittings without over-stressing the PBT resin body threads.
  • Route electrode signal cables from the holder to the control panel in a dedicated conduit or cable tray, physically separated from power conductors, to minimize electrical noise pickup on the low-voltage sensing circuit.
  • Terminate each electrode cable at the corresponding terminal on the Omron conductive level controller per the wiring diagram; confirm common, low-level, and high-level terminals are correctly mapped before energizing.
  • For PS-3SR installations, note that the 6.8 kΩ built-in resistor is already present in the holder head — verify the controller wiring documentation confirms this configuration is required before substituting PS-3SR for PS-3S or vice versa.

Full installation and wiring procedures are detailed in the Omron manufacturer documentation for the PS-[]S(R)/-31 electrode holder family and the applicable 61F controller instruction sheet. Always de-energize and lock out control circuits before opening the tank or working on electrode connections.

Compatible Electrodes and System Components

The PS-3S is one component in a conductive level sensing assembly. The following Omron components make up a complete system:

  • Omron F03-01 electrode rods — the conductive sensing rods inserted into the PS-3S holder; purchased separately and cut to installer-defined lengths for each level setpoint.
  • Omron 61F series conductive level controllers — the panel-mounted controllers that provide excitation voltage to the electrodes and drive pump or valve output relays based on liquid contact.
  • PS-3SR — the R-variant of the same 3-electrode holder, including a 6.8 kΩ built-in resistor for controller configurations that require it; a direct form-factor alternative when the resistor is specified.
  • PS-4S / PS-5S — the 4- and 5-electrode holders in the same PS-[]S(R) family, used when additional sensing points are required and the same F03-01 rod and controller ecosystem is in use.
  • PS-31 — the single-piece compact electrode holder in the same Omron family, suited to mounting configurations where the standard PS-3S format does not fit mechanically.

Wrong-Part Prevention Checklist Before You Submit the PO

Before releasing the purchase order for the Omron PS-3S, verify every item on this checklist against your design documents and control panel drawings:

  1. Confirm 3 electrodes are sufficient for the intended control logic (common, low, high) and no extra alarm or interlock electrodes are required.
  2. Verify whether the controller requires an integrated resistor version (PS-3SR) or a standard holder (PS-3S) without the R suffix.
  3. Check compatibility with Omron F03-01 electrode rods (thread, diameter, and length) and that the tank depth matches available electrode length.
  4. Confirm operating environment is within -10 to 70°C and at atmospheric pressure; not exposed to steam, vacuum, or high-pressure washdown.
  5. Ensure the liquid is a conductive water-based medium (e.g., tap water, wastewater) and not oil or highly resistive fluid.
  6. Validate mechanical mounting dimensions versus tank top openings, brackets, and any existing pipe fittings or flanges.
  7. Check that local electrical codes and panel layout allow routing of low-voltage electrode wiring away from power cables to minimize noise.
  8. Verify that the product SKU ordered (PS-3S vs PS-3SR vs PS-31 etc.) matches the drawing and BOM; double-check that the "3S" model, not "31" or "4S/5S," is on the purchase order.

If any item on this checklist raises a question before you commit, contact the LeadTime.ca team — we can verify compatibility against your controller model and check real-time stock before the order is placed.

Frequently Asked Questions

What is the difference between the PS-3S and the PS-3SR, and how do I know which one my 61F controller needs?

The PS-3S is the standard 3-electrode holder without a built-in resistor. The PS-3SR includes a 6.8 kΩ built-in resistor within the holder head. Which version your system requires depends on the specific Omron conductive level controller model and its wiring documentation — some controller configurations call out the R variant explicitly. Check the wiring diagram for your 61F or equivalent controller before ordering; if the drawing specifies the R model, order PS-3SR, not PS-3S.

Can I use the PS-3S with non-potable or lightly dirty water, and what maintenance does that require?

The PS-3S is suitable for conductive water-based liquids including light wastewater and non-potable water, provided the fluid temperature stays within -10 to 70°C and pressure remains at atmospheric. In dirtier water, electrode fouling from scale, biofilm, or suspended solids is the primary maintenance concern — it can bridge adjacent electrode rods and cause false level signals. Plan for periodic inspection and cleaning of the F03-01 electrode rods, and document cleaning intervals at commissioning based on the specific water quality of the application.

How do I set the correct electrode lengths to achieve my pump cut-in and cut-out levels?

Omron F03-01 electrode rods are installed into the PS-3S holder and cut to length by the installer on site. The common electrode is set at the lowest point (below the low-level electrode), the low-level electrode at the pump-start setpoint, and the high-level electrode at the pump-stop setpoint. After initial installation, fill and drain the tank to verify actual switching points, adjust electrode lengths if the cut-in or cut-out levels do not match the process requirement, and document the final lengths in the as-built records for future maintenance.

What are the most common causes of false trips with the PS-3S, and how are they resolved?

False level signals most often result from three sources: electrode fouling that electrically bridges adjacent rods, electrical noise coupling into the low-voltage signal cables, or loose terminal connections at the holder or controller. Cleaning the electrodes resolves fouling-related false trips. Running shielded signal cable in a dedicated conduit physically separated from power conductors addresses noise-related issues. Checking and re-tightening all terminal screws at the holder and controller corrects connection-related intermittent faults.

Is the PS-3S a direct mechanical replacement for the PS-31 in an existing installation?

The PS-3S and PS-31 are both 3-electrode holders in the Omron PS-[]S(R)/-31 family but have different mechanical formats — the PS-31 is a single-piece compact design intended for specific mounting configurations. They are not guaranteed to be direct drop-in replacements without verifying that the mounting interface, tank opening dimensions, and wiring entry geometry are compatible. Confirm the mechanical format against the existing installation drawing before substituting one for the other.

What is the typical lead time for the PS-3S in Canada, and should I keep a spare on hand?

The PS-3S is generally stocked by major industrial automation distributors serving North America, and lead times for in-stock orders are typically short. For non-stock or bulk orders, lead times can range from several days to a few weeks depending on the distributor and order size. Given that the PS-3S is a low-cost accessory relative to the cost of pump downtime, keeping at least one spare on hand for critical applications — building water supply, sump pump circuits — is a practical maintenance decision. Contact LeadTime.ca to confirm current stock status and lead time before scheduling a critical installation or shutdown.

Why Order Through LeadTime.ca

  • Global shipping — LeadTime.ca fulfills orders worldwide, not limited to any single country or region.
  • Variant verification — our team can confirm whether your controller and design require PS-3S or PS-3SR before the order ships, reducing wrong-part returns.
  • Real-time stock checks — we can confirm current Canadian and North American inventory status before you commit to a build or maintenance schedule.
  • Volume and project pricing — contact us for pricing on larger quantities or multi-line automation orders.
  • Specialist sourcing — we stock and source industrial automation components that generic catalog channels may not hold or may not be able to verify for application compatibility.

At-a-Glance Summary

  • The Omron PS-3S is a 3-electrode resin holder from the PS-[]S(R)/-31 family, used with Omron conductive level controllers for water-based level sensing applications.
  • Body material is PBT (polybutylene terephthalate) resin; minimum insulation resistance is 100 MΩ.
  • Operating range: -10 to 70°C at atmospheric pressure; no icing, no steam, no vacuum, no pressure above atmospheric.
  • Compatible electrode rods: Omron F03-01, purchased separately and cut to length by the installer.
  • Standard PS-3S has no built-in resistor; PS-3SR includes a 6.8 kΩ built-in resistor — verify which variant your controller requires before ordering.
  • For 4- or 5-point control schemes, the PS-4S or PS-5S is required; for compact mounting formats, evaluate the PS-31.
  • Primary applications: building water supply tanks, sump pump circuits, HVAC make-up water, cooling tower basins, light industrial process water.
  • Not suitable for non-conductive fluids, oils, aggressive chemicals, high-temperature process vessels, or hygienic stainless applications.
  • Pricing is available on the product page; contact LeadTime.ca for current stock status and volume pricing.

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