Series-TTW

Supported Applications

The Dwyer Series TTW Weatherproof Immersion Temperature Transmitter integrates a TBU series head-mounted transmitter, a Pt100 RTD sensor (TE Series Curve D), and an A-709 enclosure into a single package. The unit is designed for weatherproof immersion applications, specifically cited for temperature sensing in HVAC systems.

Operating Conditions & Performance

The transmitter features a factory-programmed output range of 32 to 212°F (0 to 100°C), though the internal sensor and electronics support broader limits. The Pt100 RTD temperature sensor operates from -40 to 302°F (-40 to 150°C) with an accuracy of ±3°F (±1.7°C). The transmitter input range extends from -328 to 986°F (-200 to 530°C), providing a measurement accuracy of ±0.2% FS and a response time of <100 ms.

Environmental limits for the painted aluminum housing are rated NEMA 4X (IP66) with an operating temperature range of -40 to 212°F (-40 to 100°C). The transmitter electronics operate within a process ambient limit of -40 to 185°F (-40 to 85°C).

Electrical Specifications

• Output Signal: Two-wire 4-20 mA (600 Ω @ 24 VDC load resistance)
• Power Supply: 12 to 35 VDC
• Sensor Excitation Current: 0.8 mA (for Pt100 simulator compatibility)

Configuration Options

The Series TTW is offered with fixed probe insertion lengths to accommodate various immersion depths. The standard configuration includes a machined thermowell; NPT connections are available as an option.

Model Configurations by Probe Length

• TTW-104: 4" probe length
• TTW-106: 6" probe length
• TTW-108: 8" probe length
• TTW-112: 12" probe length
• TTW-118: 18" probe length

Housing and Physical Dimensions

The unit features a painted aluminum housing with an overall length of 5 [127] mm and a diameter of Ø3-15/64 [Ø82.15]. The stem length is documented as 2-15/64 [56.75], with the probe insertion extending +3/8 [9.52] beyond the housing face.

Configuration and Accessories

The transmitter includes a USB port for field adjustment of the output scale via free software download (Series TBU-00). Machined thermowells are available in 304 SS with lengths ranging from 4" to 12", featuring internal/external NPT connections.

Key Product Differences

The primary variation within the Series TTW is the probe insertion length, designated by the model suffix (e.g., -104 through -118). The series supports optional machined thermowells with 304 SS construction and NPT process connections. While the standard unit is factory preset to a specific output range, field adjustment of the scale is supported via USB interface.

Important operational notes include that the Series TTW is not field serviceable; repair attempts may void the warranty. The USB connection port is not electrically isolated from the transmitter input. Additionally, sensor signal conductors should be routed separately from power leads where possible.