JUMO EMF Series Mechanical Temperature Switch / Thermostat (EMF-23)
The JUMO EMF-23 is a heavy-duty, industrial-grade mechanical surface-mounted or panel-mounted temperature switch (thermostat) designed for reliable temperature control, monitoring, and safety thermal limitation. Operating on the principle of liquid expansion, this highly dependable instrument features a rugged mechanical microswitch driven by a liquid-filled capillary tube and sensing bulb. Housed in a durable, impact-resistant industrial casing, the EMF-23 functions entirely without external electrical control power, making it an ideal choice for fail-safe overheating protection, process thermal tracking, and safety interlocks in demanding industrial machinery and heating systems.
Key Features
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Power-Free Liquid Expansion Principle: Utilizes a fluid-filled measuring system that expands against an internal micro-diaphragm as temperature changes, providing precise, crisp contact switching entirely independent of external electrical supply lines.
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Highly Configurable Design: Features an internal mechanical adjustment dial (accessible under a protective housing cover or as a front panel layout) to set specific switching or limit thresholds cleanly.
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Snap-Action Microswitch System: Outfitted with high-capacity SPDT (Single Pole Double Throw) silver contacts that switch instantly when reaching the set threshold, avoiding contact chatter or arcing even under slow process shifts.
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Flexible Copper or Stainless Steel Capillary: Equipped with a flexible, armored capillary tube that allows the heavy sensing bulb to be located deep within fluid wells, pipelines, or ducts while keeping the switch body safely accessible on the control board or frame wall.
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Robust Industrial Enclosure: Packaged in a compact, rugged housing with integrated mounting tabs and a standard cable entry knockout gland to maintain seal integrity in harsh factory environments.
Technical Specifications
| Feature | Specification |
| Model Series | EMF-23 (EMF Series) |
| Brand | JUMO GmbH & Co. KG |
| Product Type | Mechanical Capillary Thermostat / Temperature Switch |
| Operating Principle | Liquid Expansion (Hydraulic) |
| Contact Configuration | 1 x SPDT (Single Pole Double Throw / Changeover contact) |
| Switching Capacity (Max) | Up to 16 A at 230 V AC (Resistive) / 2.5 A (Inductive, cos phi = 0.6) |
| Sensor / Capillary Material | Copper or Stainless Steel (Model specific options available) |
| Housing Dimensions | Compact block profile with integrated side-mounting brackets |
| Ingress Protection Rating | Typically IP40 to IP54 (Depending on final installation configuration) |
| Approvals & Compliance | DIN EN 14597 certified configurations available, CE Marked, RoHS Compliant |
Applications
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Industrial Furnace & Boiler Monitoring: Serving as a primary high-limit safety cut-out switch to prevent thermal runaway in gas, oil, or electric water-heating boilers.
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Hydraulic Fluid Power Units (HPUs): Monitoring hydraulic oil reservoir temperatures to alert control systems or activate forced-air oil cooling systems before fluid breakdown occurs.
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Heat Exchangers & Pipelines: Regulating localized temperature limits on industrial steam tracing, cooling water lines, and chemical processing heat exchangers.
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HVAC Air Duct System Safety: Acting as an anti-freeze protection thermostat or an over-temperature cut-out in large facility ventilation air handling units (AHUs).
