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Ranco A30-3618 HVAC control SPST 30 inch capillary 17 degree differential

Ranco

Ranco A30-3618 hvac control SPST 30" cap 17 deg F

SKU CH-WQT9-91WA5

A single-pole single-throw HVAC temperature control with a 30-inch capillary and a 17-degree Fahrenheit differential

  • SPST switching simplifies wiring for heating or cooling circuits
  • 17 deg F differential prevents short cycling and maintains stable temperature
  • 30 inch capillary allows remote sensor placement in duct or coil
  • Ranco A30-3618 replaces original equipment controls in compatible HVAC systems

Ranco A30-3618 HVAC Temperature Control

The Ranco A30-3618 is a single-pole single-throw temperature control designed for HVAC systems. It uses a 30-inch capillary tube to sense temperature changes in ducts, tanks or remote locations. The switch opens or closes a circuit based on the set point, making it suitable for heating or cooling equipment that requires basic on-off regulation. Installers and maintenance technicians use it where a mechanical thermostat with a remote bulb is specified.

17-Degree Differential and Capillary Reach

The control operates with a fixed 17-degree Fahrenheit differential between cut-in and cut-out temperatures. This wide gap prevents short-cycling on systems that tolerate broader temperature swings, but it is not suitable for processes needing tight tolerance. The 30-inch capillary limits placement to locations within that distance from the controller body. Applications requiring a narrower differential or a longer capillary run will need a different model.

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Price $53.99
Typical for this category: the median of 1,762 items is $45.99.

Specifications

Product
Brand nameRANCO

Questions about this item

Will the 30-inch capillary tube reach the evaporator coil on my older walk-in cooler?

The 30-inch capillary provides a fixed sensing length; measure the distance from your control mounting location to the coil to confirm it reaches without stretching or kinking the tube.

How do I verify the SPST switch is cycling correctly at the 17-degree differential after installation?

Monitor the system with a thermometer; the compressor should start at the setpoint and stop once the temperature drops 17 degrees Fahrenheit, confirming the differential is functioning.

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