Honeywell T678A1361 Contorller

Remote Bulb Controller, Regulates Temperature of Air or Liquids in Ducts, Pipes, Tanks and Boilers, 120Vac or 240/277Vac, 55-175 Degree Setpoint Temperature Range, 200 Degree Maximum Operating Temperature, 3.6 Degree Fixed Differential Temperature, 3.6-12 Degree Interstage Differential Temperature, 1/2"x3 9/16" Copper Bulb, 20' Capillary Length, 2 SPDT Output, Can be Mounted in any Position

T678A1361 is the direct replacement for HH29AA080, T478A1002

Honeywell T678A1361 Remote Bulb Temperature Controller

The Honeywell T678A1361 Remote Bulb Controller provides precise temperature regulation for air or liquids in ducts, pipes, tanks, and boilers. Designed for commercial and industrial HVAC applications, this reliable controller offers consistent performance in demanding environments.

Featuring a 55°F–175°F setpoint temperature range and a maximum operating temperature of 200°F, the T678A1361 ensures optimal control accuracy. It operates on 120V, 240V, or 277V AC and includes two SPDT output relays for versatile integration into heating, cooling, and dual-temperature systems.

The unit includes a 1/2" x 3-9/16" copper sensing bulb with a 20-foot capillary length, allowing the controller to be installed remotely from the sensing point. With a fixed 3.6°F differential and 3.6°–12°F interstage differential, it delivers reliable and responsive performance.

The Honeywell T678A1361 can be mounted in any position, and its ambient temperature compensation ensures stable operation even under variable conditions.

Key Features

• Regulates temperature of air or liquids in ducts, pipes, tanks, and boilers

• Operates on 120V, 240V, or 277V AC (50/60 Hz)

• Temperature range: 55°F–175°F (200°F max operating)

• Differential: 3.6°F fixed, 3.6°–12°F interstage differential

• Sensor: Copper bulb, 1/2" x 3-9/16" with 20' capillary

• Output: 2 SPDT relay contacts

• Mounting: Any position; ambient-compensated design

• Dimensions: 5-5/8" H × 2" W × 2-5/8" D

• Max connected load: 2000 VA

Applications

• Temperature control for air ducts, boilers, and water systems

• Heating and cooling system control

• Suitable for commercial and industrial HVAC applications

• Controls valves, dampers, and pumps in temperature-regulated environments

Specifications Summary:

• Voltage: 120/240/277 VAC

• Frequency: 50/60 Hz

• Output Type: Relay (2 SPDT contacts)

• Sensor Type: Copper bulb

• Capillary Length: 20 feet

• Temperature Range: 55°F to 175°F

• Max Operating Temp: 200°F

• Mounting Orientation: Any position

The Honeywell T678A1361 Remote Bulb Controller is an industry-standard solution for accurate, durable, and flexible temperature control in commercial and industrial systems.