Pressure Switch Replacements
Upgrade guide for Siemens QPL pressure switches and other discontinued sensors.
Connection Type Alert
Siemens QPL series has two distinct connection types: QPL15 (O-ring) and QPL25 (1/4" Thread). Mixing these up will prevent installation. Verify the exact model code before ordering.
Replacement List
| Brand | Discontinued Model | End of Life | Official Replacement | Key Differences | Interchange? | Action / Advice |
|---|---|---|---|---|---|---|
| Siemens | QPL25.003 | Discontinued | QPL25.003B | B-version is the direct successor. Check 1/4" Thread vs O-ring. | Yes | Replace after 10 years / 50k cycles. |
| Siemens | QPL25.050 | Discontinued | QPL25.050B | B-version is the direct successor. Check connection type. | Yes | Check range and setpoint. |
| Siemens | QPL15.150 | Discontinued | QPL15.150B | B-version is the direct successor. QPL15 uses O-ring connection. | Yes | Ensure O-ring seal integrity. |
| Siemens | QPL25.500 | Discontinued (Regionally) | QPL25.500B | B-version is the direct successor. | Yes | Verify availability with authorized distributor. |
Priority Procurement & Maintenance Advice
- Lifecycle Management: Siemens recommends replacing pressure switches after ~10 years or 50,000 cycles. Don't wait for failure.
- B-Version Migration: Systematically upgrade all QPL switches to the "B" version (e.g., QPL25.003B) to unify spare parts inventory.
- Setpoint Verification: After replacement, always verify the High/Low pressure trip points and interlock function.