WIKA TG51 Bimetal Thermometer

Fits local mechanical temperature indication on process lines where you need a hermetically sealed 304 SS bimetal thermometer, axial or radial mount, and no electrical output.

Key advantages

• ASME B40.3 Grade A accuracy — ±1.0% full scale on published dial ranges from −100 °F to 1000 °F (−70 °C to 540 °C).
• Hermetic 304 SS case — IP66 / NEMA 4X with ¼″ stem and L1 insertion options 2.5″…24″.
• Mount flexibility — 3″ or 5″ dial; axial (back) or radial (lower); plain / ¼ NPT / ½ NPT.
• Field options — Inert gel damping and thermowell-compatible stems when vibration or well mounting is required.

Typical applications

• Local process-line temperature indication where a mechanical dial is preferred over a transmitter.
• Skid and utility piping that needs a sealed stainless thermometer without loop power.
• Panel or vessel wells that require axial or radial head orientation locked at order.

Selection guide

• Measuring range — From −100 °F to 1000 °F (−70 °C to 540 °C) standard range tables. Lock the dial range to the process max.
• Sensor — Bimetal coil. Inert gel damping option available.
• Accuracy — ±1.0% full scale per ASME B40.3 Grade A.
• Output — Mechanical dial indication only (no electrical output).
• Dial / head — 3″ or 5″ dial; back mount (axial) or lower mount (radial). White aluminum dial, black outer / red inner scale; black pointer.
• Stem — Diameter ¼″ [6.35 mm]; insertion length L1 2.5″…24″ (63.5…609.6 mm).
• Process connection — Plain without thread; ¼ NPT; ½ NPT.
• Case / stem material — 304 stainless steel hermetically sealed case; sheath 304 stainless steel.

Common mistakes

• Ordering radial (lower) mount when the panel needs axial (back), or the reverse — head orientation is a model choice.
• Undersizing insertion length L1 (2.5″…24″) so the bimetal coil sits outside the active process fluid.
• Ignoring window ambient limits (instrument glass vs safety glass/PC) and fog/ice below 32 °F.
• Expecting an electrical output or transmitter — TG51 is mechanical dial only.
• Claiming ATEX/CE from this page — approvals were not listed in the OEM documentation; ask if marks are required.

When to RFQ / what to tell us

1. Dial range (°F or °C) within −100…1000 °F (−70…540 °C) tables.
2. Dial size (3″ or 5″) and mount (axial/back vs radial/lower).
3. Insertion length L1 (2.5″…24″) and connection (plain / ¼ NPT / ½ NPT).
4. Inert gel damping yes/no; window type (instrument glass vs safety glass/PC); thermowell yes/no.
5. Any mark/ingress needs beyond IP66/NEMA 4X, quantity, ship-to country.

Request a Quote · Get selection help

Specs

Documents

• WIKA TG51 datasheet (PDF)

FAQ

Q: Axial or radial — which mount do I need? A: Back mount (axial) when the stem enters from behind the dial; lower mount (radial) when the stem leaves the bottom of the case. State orientation in the RFQ.

Q: What stem lengths are available? A: Insertion length L1 2.5″…24″ (63.5…609.6 mm) at ¼″ [6.35 mm] diameter. Size immersion so the coil is in the active fluid.

Q: Are ATEX or CE listed on this page? A: Not on the OEM documentation used. IP66 / NEMA 4X is published. Call out any required marks in the RFQ so we can confirm against current OEM docs.

Q: What should I send for a quote? A: Range, dial size/mount, L1 and connection, damping, window type, thermowell, quantity. Compatible with systems using WIKA TG51 if you need a drop-in check — we do not claim authorized-dealer status.

Links

• Temperature instruments · Thermometer buying guide
• Request a Quote · Get selection help