SX7-SX9-Series

Supported Applications

The Miljoco SX7 and SX9 series are liquid-in-glass industrial thermometers designed for commercial construction and industrial applications, including piping systems and air ducts. These instruments are intended for installation in separable sockets or test wells to protect the sensing element against fluid erosion, corrosion, or other hazards. The product overview notes suitability for HVAC systems when used with proper priming.

Operating Conditions & Performance

The series features a precision die-cast aluminum case with a green powder coat finish and utilizes blue reading liquid fill behind a magnifying glass lens. Accuracy is specified as ±1 scale division across the available ranges. The ambient operating temperature range is -40 to 140°F (-40 to 60°C).

Measurement scales are offered in single or dual units (°F and °C) with various spans, including:

• -40 to 110°F
• 0 to 120°F / -10 to 50°C
• 30 to 240°F / 0 to 115°C
• 50 to 400°F / 10 to 205°C
• -50 to 550°F (single scale)

A critical operational constraint is that the stem must not be exposed to temperatures more than 20°F above the high end of the scale, as this may cause irreparable damage. The series includes pressure/temperature ratings for wetted materials: Brass supports up to 1600 psi at 70°F; 304SS and 316SS support higher pressures depending on temperature (e.g., 2300 psi at 70°F).

Configuration Options

The SX7-SX9 series is configurable across scale size, stem length, process connection type, wetted materials, and optional accessories.

• Scale Size: Available in 7" (SX7) or 9" (SX9) models. Overall dimensions are approximately 8.38" for the 7" model and 10.38" for the 9" model.
• Stem Lengths: Options include 3½" and 6" stems, with specific immersion lengths (e.g., 2.50", 1.50", 5.00") depending on lagging extension requirements.
• Process Connections & Wetted Materials: The standard process connection is a 1-1/4"-18 UNF threaded brass coupling nut for adjustable angle mounting. Stem materials include Brass, 304 Stainless Steel (SS), and 316 SS. Specific part codes denote material combinations such as W35B (Brass) or W35304 (304SS).
• Optional Features: Available options include a Glass Lens (Code G), Brass Stem (BS), Stainless Steel Stem (SS), Air-Duct Stem, Thermowell cap & lanyard (WCCB), Lead-Free Brass availability, and Waterproof Cover.

Key Product Differences

The series distinguishes between the SX7 family with a 7" scale size and the SX9 family with a 9" scale size. Model numbers follow the pattern SX[Scale][Stem Length], such as SX735 (7", 3½") or SX960 (9", 6"). Range codes appended to the model number define the specific temperature span and graduation, for example, Code 35 corresponds to a 0 to 120°F range with 1° divisions. The series supports both single-scale Fahrenheit readings and dual-scale Fahrenheit/Celsius configurations.

Installation instructions specify that these thermometers are supplied with non-toxic spirit-filled tubes; mercury-filled units require hazardous material disposal if damaged. Users must not install the thermometer directly into a pressurized hydronic HVAC system or process media without an intermediate socket, and the angle adjustment screw should not be removed during installation.