Retrofitting Level Switches: Upgrade Without Replacing Piping
Updated: Aug 6
When a level switch fails or needs upgrading, the instinct is often to replace the entire assembly — chamber, piping, and all. But that's rarely necessary. The Jerguson Tri-Magnet Level Switch allows you to retrofit an existing switch mechanism without touching the piping or chamber at all. Here's how the process works and why it matters for maintenance planning.
The Problem with Traditional Switch Replacement
Why Full Replacement Is Costly and Disruptive
Traditional level switch replacement typically requires:
Draining and isolating the entire system
Removing the chamber from process piping
Breaking pipe connections and unions
Installing new chamber and reconnecting piping
Pressure testing the new connections
Extended downtime while piping work is completed
For a single switch failure, this level of disruption is excessive. In many cases, the chamber and float mechanism are still functional — only the switch housing or sensing element has failed or needs upgrading.
When Retrofit Makes Sense:
Existing switch mechanism has failed (electrical or mechanical fault)
Upgrading from mechanical to magnetic switch technology
Switching switch type (SPDT to DPDT, or adding additional switch points)
Original switch is obsolete and parts are unavailable
Chamber and float assembly remain in good working condition
How the Tri-Magnet Retrofit Works
The Jerguson Tri-Magnet Level Switch is specifically engineered to convert existing float-and-rod assemblies without requiring any piping modifications.
The Retrofit Procedure:
Step 1: Remove Old Components Remove the old housing, switch mechanism, and pressure tube. This exposes the existing float rod that remains connected to the float inside the chamber.
Step 2: Remove Old Attraction Sleeve If the existing design used a magnetic attraction sleeve, remove it from the float rod. This clears the rod for the new Tri-Magnet components.
Step 3: Install New Float Tube and Magnet Fit the new float tube and permanent magnet assembly onto the existing float rod. This becomes the new magnetic sensing element.
Step 4: Install Tri-Magnet Switch Assembly Slide the Tri-Magnet switch assembly over the magnet and rod, then tighten the retaining nut to secure it in position.
Step 5: Verify Operation The retrofit is complete. No piping changes were required — the chamber, float, and process connections remain untouched throughout the entire procedure.
Why This Retrofit Approach Works
Magnetic Coupling Eliminates Piping Dependency
The Tri-Magnet design uses magnetic coupling between the internal float assembly and the external switch mechanism. Since there's no direct mechanical or electrical connection crossing the pressure boundary, the switch can be changed without breaking into the pressurized system.
Float Rod Compatibility
Most existing float-and-rod assemblies are compatible with Tri-Magnet retrofit components, since the rod itself doesn't need modification — only the external switch mechanism changes.
Retrofit vs. Full Replacement
Factor | Tri-Magnet Retrofit | Full Chamber Replacement |
Piping Work Required | None | Full disconnect/reconnect |
System Downtime | Minimal (hours) | Extended (days) |
Pressure Testing | Not required | Required after reconnection |
Process Isolation | Brief (switch area only) | Extended (full system) |
Chamber Condition Required | Must be in good condition | N/A (chamber is replaced) |
Complexity | Low (mechanical swap) | High (piping + electrical) |
When Retrofit Is NOT Appropriate
Retrofit is not suitable if:
Chamber itself is damaged (corrosion, cracks, structural issues)
Float rod is bent or damaged (won't move freely for magnetic sensing)
Process conditions have changed significantly (different pressure/temperature rating needed)
Complete system upgrade is planned (new chamber technology desired)
In these cases, full replacement remains the appropriate solution.
Applications for Level Switch Retrofits
Power Generation Feedwater tank level alarms, condensate receiver switches, deaerator level control
Chemical Processing Reactor level alarms, storage tank high/low switches, batch process control points
Oil & Gas Separator vessel level switches, storage tank alarms, process vessel monitoring
Water Treatment Clarifier level control, chemical feed tank alarms, backwash initiation switches
General Industrial Any application using float-and-rod level switches that need technology upgrades or failed switch replacement
Planning Your Retrofit
Before beginning a retrofit:
Inspect the chamber — Confirm no corrosion, cracks, or structural damage
Check float rod condition — Verify smooth movement without binding
Confirm compatibility — Verify your existing float rod diameter matches Tri-Magnet specifications
Determine switch requirements — Number of switch points needed, SPDT vs. DPDT configuration
Schedule brief isolation — Even though piping isn't touched, the switch area needs isolation during the swap
Learn More
If you have level switches that need upgrading or have failed, a Tri-Magnet retrofit may eliminate the need for costly piping work. Contact Clark-Reliance to discuss compatibility with your existing installation.
📧 sales@clark-reliance.com📞 +1 (440) 572-1500
