🌬️ RFS-4100-021 CLEVELAND PRESSURE SWITCH
General Purpose Proving Switch for HVAC & Energy Management Systems
The Cleveland Controls RFS-4100-021 is a versatile air pressure proving switch engineered for dependable airflow and pressure monitoring. Designed to detect positive, negative, or differential air pressure, it’s a trusted choice for HVAC and energy management applications requiring precision and reliability.
✅ Key Features
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✅ Adjustable Setpoint Range: 0.15" to 5" WC for flexible airflow or pressure monitoring.
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✅ Multi-Function Sensing: Detects positive, negative, or differential air pressure.
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✅ Durable Construction: Plated housing with diaphragm and calibration spring.
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✅ High Reliability: Rated for 100,000+ cycles at maximum rated load.
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✅ Simple Installation: ¼" OD compression fittings and ¼" 90° quick-connect terminals.
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✅ Flexible Mounting: Can be installed with diaphragm in any vertical plane.
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✅ Trusted in HVAC Systems: Commonly used in fans, blowers, duct pressure, and draft proving.
📊 Technical Specifications
| Specification | Detail |
|---|
| Manufacturer |
Cleveland Controls |
| Model |
RFS-4100-021 |
| Type |
Air Pressure Proving Switch |
| Setpoint Range |
0.15" – 5" WC |
| Pressure Type |
Positive, Negative, or Differential |
| Maximum Pressure |
½ psi (0.03 bar) |
| Operating Temperature Range |
40°F to 180°F (–40°C to 82.2°C) |
| Mounting Position |
Diaphragm in any vertical plane |
| Electrical Connections |
¼" 90° Quick-Connect Spade Terminals |
| Tubing Connection |
¼" OD Rigid Tubing (Compression Fitting) |
| Cycle Life |
100,000 cycles minimum at rated load |
⚠️ Notes
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Mount with the diaphragm in a vertical plane for accurate operation.
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Designed for air and compatible gases only – not for liquid pressure sensing.
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Keep tubing dry and debris-free to prevent false readings or switch failure.
🔧 Common Applications
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HVAC airflow or draft proving
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Fan and blower status monitoring
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Filter restriction indication
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Boiler and furnace pressure safety control
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Energy management systems and control panels
⚠️ Common Symptoms of a Faulty Pressure Switch
If your RFS-4100-021 or similar pressure switch is failing, you may notice:
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🚫 Blower or fan won’t start even when the system calls for air.
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🔄 Unit cycles on and off frequently or fails to maintain airflow.
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💡 Error codes or lockout indicating airflow or pressure faults.
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🕳️ Weak or delayed ignition in boiler or furnace systems.
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📉 Inconsistent system performance or airflow pressure readings.
Tip: Before replacing the switch, check tubing for clogs, cracks, or moisture buildup — these often mimic switch failure symptoms.
💡 Shopping Tips
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🧭 Verify Setpoint Range: Confirm your required pressure range is within 0.15"–5" WC.
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🔄 Match Electrical Ratings: Ensure your system voltage and switch function align with this model.
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⚙️ For Air Only: Do not use for liquid or refrigerant applications.
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💧 Maintenance Tip: Keep sample lines dry and clean to avoid false triggering.
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🔁 Replacement: Fits most systems using Cleveland Controls RFS-4000 series switches.
❓ Frequently Asked Questions (FAQ)
Q: Can this switch detect both positive and negative pressure?
A: Yes — it can detect positive, negative, or differential air pressure, depending on the tubing configuration.
Q: How should it be mounted?
A: Always mount with the diaphragm in a vertical plane for accurate calibration.
Q: Is this switch compatible with outdoor units?
A: Yes, but it must be protected from direct water exposure. Use a weatherproof enclosure if installed outdoors.
Q: What size tubing does it use?
A: It accepts ¼" OD rigid tubing with built-in compression ferrules and nuts.
Q: How do I know if my old switch is bad?
A: If your fan or blower won’t start, or you’re seeing airflow fault codes, the pressure switch is a likely culprit.
