1-385HL 0.385" Bore Dia Threaded Heavy Duty Lagging Thermowells

Supported Applications

The Omega Series 385HL is a heavy-duty thermowell designed for temperature measurement applications involving water, steam, air, and gas. It accommodates standard length, ⅜" stem bimetal thermometers, #14-gage thermocouple elements, armored liquid-in-glass test thermometers, and other temperature-sensing elements with a maximum diameter of 0.377".

These wells are compatible with OMEGA® NB1, NB2; PR-12, PR-14, and NPT-style probes, as well as DialTemp™ Thermometers.

Operating Conditions & Performance

The Series 385HL features a standard external thread process connection of "P" – 1 NPT. The internal bore diameter is specified at ±0.002 with a nominal size of 0.385", and the shank diameter (Q) measures 1⅛".

Maximum fluid velocity ratings vary by material and insertion length, as documented in the series specifications:

• Brass (ASTM B-16): Ratings range from 321 ft/s for a 2½" insertion to 5.1 ft/s for a 22½" insertion.
• Carbon Steel (C-1018): Ratings range from 410 ft/s for a 2½" insertion to 9.8 ft/s for a 22½" insertion.
• A.I.S.I. 304 & A.I.S.I. 316 Stainless Steel: Ratings range from 483 ft/s for a 2½" insertion to 10.7 ft/s for a 22½" insertion.
• Monel®: Ratings range from 396 ft/s for a 2½" insertion to 7.7 ft/s for a 22½" insertion.

Note: Where single values appear in velocity tables, they are considered safe for water, steam, air, or gas. Values in parentheses represent safe limits specifically for water flow at higher velocities; unbracketed values apply to steam, air, gas, and similar density fluids. Pressure-Temperature ratings require reference to omega.com.

Configuration Options

The series supports a range of configurations defined by lagging extension (T), stem length (A), insertion length (U), and wetted material code (*). The standard model number format is 1-385HL-<Lagging Extension>-<Stem Length>-<Insert Length>-<Material Code>>.

Available dimensional options include:

• Lagging Extensions (T): 2" or 3".
• Stem Lengths (A): 6, 9, 12, 15, 18, and 24 inches.
• Insertion Lengths (U): 2½, 4½, 7½, 10½, 13½, 19½, and 22½ inches.

Wetted materials are available in:

• Brass (ASTM B-16)
• Carbon Steel (C-1018)
• A.I.S.I. 304 & A.I.S.I. 316 Stainless Steel
• Monel®

PFA coating is available upon request. Other thread sizes beyond the standard 1 NPT are offered upon request.

Key Product Differences

The Series 385HL distinguishes itself from other series by its specific bore diameter of ±0.002 at 0.385" and a shank diameter (Q) of 1⅛", designed specifically for elements up to 0.377" in diameter.

Material selection impacts maximum fluid velocity ratings, with A.I.S.I. 304 & 316 stainless steel generally offering higher limits than Monel® or Carbon Steel at equivalent insertion lengths. For example, at a 2½" insertion length, the rating for Stainless Steel is 483 ft/s compared to 410 ft/s for Carbon Steel.

Optional accessories include cap and chain configurations:

• -CC-Brass: Adds a brass cap (additional cost).
• -CC: Adds a 304SS cap (additional cost).

Metric models are available; see omega.com for details. The series is manufactured in the USA.