Honeywell Bath Controls

Overview

The HONEYWELL T991A1012 is a proportional temperature controller designed for precise modulating control in HVAC and building automation applications. It uses a capillary-and-bulb sensing element to detect temperature changes and modulate a controlled device output in proportion to the deviation from setpoint rather than switching fully on or off. This proportional action reduces temperature swings and improves system stability. The unit features a 4.1875-inch bulb length and a 20-foot capillary, giving technicians flexible placement of the sensing element relative to the controller body. Licensed HVAC technicians and building automation specialists are the primary installers. The T991A1012 is suited for residential and light commercial HVAC systems where proportional temperature control is preferred over simple two-position switching. Typical applications include duct-mounted or immersion sensing in air handling units, fan coil units, and similar hydronic or forced-air systems. The 20-foot capillary allows the sensing bulb to be positioned at a remote location while the controller body mounts in an accessible panel or wall enclosure. Key Features Proportional control action minimizes temperature overshoot and reduces cycling 4.1875-inch sensing bulb length for reliable thermal response 20-foot capillary allows remote bulb placement away from the controller body Capillary-and-bulb sensing element eliminates need for separate temperature sensor wiring Compact form factor…