Siemens QPL25.050B is a high-performance gas pressure switch. Proiectat pentru monitorizarea presiunii medii și joase, de la 5-50 mbar, are grad de protecție IP54 și o durată de viață mecanică de 100,000 cicluri. Este utilizat pe scară largă pentru protecția de siguranță a sistemelor de ardere. Verificați parametrii modelului, intervalul de presiune și interfața de montare în timpul achiziției pentru a asigura compatibilitatea deplină cu cerințele sistemului.
- Definiția codului modelului
| Segment de cod | Sens | Descriere |
| QPL | Cod seria produsului | Basic series of Siemens gas pressure switches for gas and air pressure monitoring |
| 25 | Structura & parametrii nominali | Serie 25, rated current 6A AC, rated voltage 250V AC/DC, IP54 protection |
| 50 | Pressure adjustment range | Interval reglabil: 5-50 mbar (0.5-5.0 kPa) |
| B | Version mark | Tip standard, resetare automată, SPDT contact configuration |
- Parametrii de specificație de bază
| Categorie | Specificații | Observații |
| Parametrii de bază | ||
| Tip de produs | Mechanical gas pressure switch | Safety monitoring for combustion systems |
| Comanda nr. | 1117087 | Official Siemens part number |
| Adjustment Range | 5-50 mbar (0.5-5.0 kPa) | Adjustable set point |
| Max Working Pressure | 690 mbar (69 kPa) | Upper limit of continuous operating pressure |
| Switch Differential | Aproximativ. 5-10 mbar | Pressure difference between switch-on and switch-off |
| Parametrii electrici | ||
| Tensiune nominală | AC 250V / DC 250V | Maximum operating voltage |
| Curent nominal | AC 6A / DC 1A | Sarcină rezistivă |
| Tip de contact | SPDT | 1 deschis în mod normal + 1 în mod normal închis |
| Conexiune electrică | Terminal box compliant with DIN EN 175 301-803 | Clasă 3 protecția izolației |
| Mecanic & Parametrii de mediu | ||
| Pressure Port | G1/4 internal thread (ISO228) | Center position at bottom casing |
| Measuring Port | Ø9mm, 10mm length with locking screw | For pressure calibration |
| Temperatura ambiantă | -20°C ~ +60°C | Interval de temperatură de funcționare |
| Medium Temperature | -40°C ~ +60°C | Applicable gas temperature |
| Grad de protecție | IP54 | Dustproof and waterproof |
| Mechanical Lifespan | 100,000 cicluri | Switch actuation times |
| Applicable Media | Clasă 1/2/3 gases & non-corrosive gas | Natural gas, liquefied petroleum gas, etc. |
- Full QPL25 Series Model List
| Model | Interval de presiune | Max Working Pressure | Observații |
| QPL25.003B | 0.3-3 mbar | 690 mbar | Low pressure monitoring |
| QPL25.010B | 1-10 mbar | 690 mbar | Ultra-low pressure application |
| QPL25.050B | 5-50 mbar | 690 mbar | Standard medium-low pressure |
| QPL25.150B | 15-150 mbar | 690 mbar | Medium pressure monitoring |
| QPL25.500B | 100-500 mbar | 720 mbar | High pressure monitoring |
- Cross-brand Replacement Comparison
| Marca | Model | Interval de presiune | Principalele diferențe | Sugestie de înlocuire |
| Siemens | QPL25.050B | 5-50 mbar | Original authentic product, stabilitate ridicată | Priority choice |
| Honeywell | C6097A | 5-50 mbar | Lower price, similar response speed | Înlocuire directă |
| Danfoss | KPI 36 | 5-50 mbar | Different mechanical structure, high adjustment precision | Verify mounting dimensions |
| Dungs | LGW50A2 | 5-50 mbar | German brand, calitate de incredere | Complet compatibil |
| Baltur | PAMPA | 5-50 mbar | Burner dedicated, rentabil | Suitable for Baltur combustion systems |
- Depanare comună & Întreţinere
5.1 Defecte comune & Cauze
| Fenomen de eroare | Cauze posibile | Pași de depanare |
| No switch action under normal pressure | Improper setpoint; oxidized/damaged contacts; aging/damaged diaphragm; cabluri libere | Recalibrate setpoint; test contact continuity; inspect diaphragm; fasten terminals |
| No switching under abnormal pressure | Excessive switch differential; mechanical stuck; spring fatigue | Adjust differential; clean moving parts; replace spring assembly |
| Frequent contact ablation | Supraîncărcare; unstable voltage; mismatched contact material | Verificați curentul de sarcină; install surge suppressor; replace contact assembly |
| Inaccurate pressure reading | Blocked measuring port; deformed diaphragm; calibration error | Clean port; replace diaphragm; recalibrate with standard pressure source |
5.2 Ghid de întreținere
- Safety Precaution
Cut off gas supply and release pressure
Disconnect power supply
Cool down equipment to room temperature
- Calibration Procedure
① Remove protective cover and locate adjusting screw
② Connect standard pressure source and set target value
③ Clockwise rotation increases set pressure, counter-clockwise decreases
④ Test switching action and confirm accurate trigger point
⑤ Reinstall cover and ensure tight sealing
- Component Replacement
Diafragmă: Dismount with special tools, pay attention to gasket installation direction
Contact: Replace whole switch module instead of single contact
Spring: Use identical specification spare part to guarantee precision
- Mediul de aplicare & Cazuri industriale
6.1 Scenarii aplicabile
✅ Recommended Applications
Safety monitoring for industrial & civil gas burners
Pressure protection system of gas boilers
Pressure control of natural gas pipelines
Gas supply system of industrial furnaces
Pressure monitoring for biogas power generation equipment
❌ Inadmissible Applications
High-pressure gas system over 690 mbar
Corrosive gas atmosphere
Medium temperature exceeding 60°C or below -20°C
Severe vibration and outdoor exposed installation without protection
6.2 Typical Industry Applications
| Industrie | Aplicație | Funcţie |
| HVAC | Commercial gas boiler | Monitor gas pressure to ensure combustion efficiency and safety |
| Prelucrarea alimentelor | Baking furnace gas system | Avoid incomplete combustion caused by low pressure |
| Industria Energiei | Biogas power station | Stabilize biogas pressure and protect generating units |
| Fabricarea | Ceramic kiln | Precise temperature control via gas pressure regulation |
| Commercial Kitchen | Large cooking equipment | Safety interlock to prevent gas leakage accidents |
- Sfaturi de selecție & Avoidable Risks
Selection Mnemonic
QPL series for gas service, 25 stands for 6A rating
Last three digits define pressure range, B means standard auto-reset
050 model fits 5-50 mbar, G1/4 thread for installation
IP54 solid protection, match gas medium properly
Note cheie
- Pressure Matching
Keep actual working pressure within 20%-80% of adjustment range to maintain accuracy.
- Cerințe de instalare
Mount vertically with diaphragm downward to avoid condensed water accumulation.
Install filter at pressure port to prevent internal impurity damage.
Secure wiring firmly to avoid false triggering.
- Safety Regulations
Interlock with gas leakage alarm device.
Conduct regular inspection and calibration every 6 luni.
Perform pressure and leakage test after maintenance.
- Purchase Notice
Choose genuine Siemens products; counterfeit items have unstable quality.
Keep original package and certificate for after-sales service.
Working Principle of QPL25.050B
Principiul de bază: Air pressure deforms diaphragm, mechanical linkage drives contact on-off to realize overpressure interlock protection
- Pressure Sensing
Gas flows into inner chamber through G1/4 port and acts on rubber diaphragm, driving axial displacement with pressure variation.
- Mechanical Force Balance
Diaphragm thrust counterbalances preset spring tension. Rotate adjusting screw to change spring preload and set trigger pressure threshold.
- Linkage Actuation
When pressure rises to set value, diaphragm overcomes spring resistance and pushes rod to drive lever mechanism. Spring rebounds when pressure drops below threshold.
- Contact Switching
Lever movement switches SPDT contacts, reverses circuit status and transmits electric signal for burner start-stop and alarm interlock.
- Differential Pressure Stabilization
Fixed pressure differential prevents frequent switching and unnecessary equipment startup/shutdown.
- Modul de resetare
Standard automatic reset; contacts recover initial state once pressure returns to normal range.
Application Scenarios of QPL25.050B
Applicable Sites
- Low pressure monitoring and protection for gas boilers and water heaters
- Supply pressure interlock control of oil and gas industrial burners
- Pressure stabilization detection for commercial kitchen stoves and hot air furnaces
- Medium-low pressure monitoring of natural gas and liquefied gas pipelines
- Safety protection for furnace and drying equipment gas supply
- Start-stop interlock for clean combustible gas such as biogas and coal gas
Forbidden Sites
- Gas pipelines with pressure higher than 690mbar
- Gas medium containing corrosion, dust and oil contaminants
- Ambient temperature below -20℃ or above 60℃
- Sites with fierce vibration and uncovered outdoor installation
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