At Stemco Capillary Switch, a division of Senasys, we manufacture and supply high limit manual reset bulb and capillary switches used in commercial atmospheric hot water dispensers. These switches act as mechanical safety controls that shut off power to the heating element when water temperature exceeds a set limit. This helps protect the equipment from overheating and potential failure.
To view product specifications, visit our product page.
How Bulb and Capillary Switches Function as Hot Water Dispenser High Limit Controls
Each switch features a liquid-filled bulb installed in the tank to sense temperature changes. A capillary tube links the bulb to the mechanical housing, where internal pressure activates a manual reset switch once the water surpasses the temperature limit.
This setup provides accurate thermal response without relying on electronic sensing. The manual reset ensures the equipment remains off until a technician verifies safe conditions.
Why OEMs Choose Bulb and Capillary Switches
Commercial hot water systems require safety mechanisms that perform consistently in demanding environments. Bulb and capillary switches offer:
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Reliable temperature sensing inside the tank
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Mechanical operation that withstands humidity and frequent cycling
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Manual reset control to comply with commercial safety standards
OEMs integrate these switches into dispensers to manage overheat conditions while maintaining simple, serviceable designs.
DPDT Relays for Advanced Circuit Control
In some systems, designers use Double Pole Double Throw (DPDT) relay switches to manage multiple circuits or implement additional safety logic. These relays allow more complex switching setups that coordinate power shutdowns across multiple load paths.
At Senasys, we also offer DPDT relay switches suited for commercial hot water applications. Contact us for help selecting relay configurations that match your system requirements.
Made in the USA with OEM-Level Durability
Our bulb and capillary switches are manufactured in the USA and built to meet OEM requirements. Each unit delivers long service life, consistent thermal response, and compatibility with commercial heating systems. We provide:
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Fast turnaround on orders
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Straightforward pricing for OEMs and resellers
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Reliable performance backed by years of field use
For control systems that need DPDT relays, we supply robust, field-proven models that pair well with both new builds and replacement applications.
Ready to spec high limit controls or DPDT relays into your hot water dispenser design? Contact us today to speak with our product team or request a quote.
