Series-NF402

Supported Applications

Weiss Instruments Series NF402 leakproof pressure gauges are stainless steel cased, liquid-filled industrial instruments designed for severe applications involving vibration, corrosion, and pulsating conditions. The product overview identifies suitability for agricultural equipment, hydraulic systems, oil field equipment, pumps, compressors, and car wash systems.

Operating Conditions & Performance

The Series NF402 is a 4" gauge with Type 316 stainless steel wetted parts (tube and socket) housed in a type 304 stainless steel case. The series supports pressure ranges from Vacuum, Compound, to Pressure up to 5,000 psi for the NF402 model specifically; broader family capabilities extend to 15,000 psi across other sizes. Accuracy is specified as 1% of span for this series size.

Process connections are provided via a Type 316 stainless steel socket with threaded restrictor in a 1/4" NPT bottom configuration. The dial features white aluminum with black and red markings (psi & kPa), protected by safety glass. Standard filling medium is glycerine, rated for +20°F to +150°F; silicone fill is available as a special order for -40°F to 150°F service.

Key Specifications

• Accuracy: 1% of span
• Ranges: Vacuum, Compound, Pressure to 5,000 psi (NF402 specific); family ranges extend to 15,000 psi.
• Housing Material: Type 304 stainless steel case with polished stainless steel bayonet ring
• Wetted Materials: Type 316 Stainless Steel (tube and socket)
• Dial/Window: White aluminum dial; Safety glass window
• Pointer: Black anodized aluminum, micro adjustable
• Movement: Stainless steel rotary type with bushings

Configuration Options

The Series NF402 is available in various pressure ranges including vacuum and compound configurations. The standard configuration features a 1/4" NPT bottom connection, but the broader product line supports configurable mounting options for panel or wall installation.

• Mounting Options: Back Flange (Series NF402BF) is available as an option; U-Clamp and Front Flange mountings are offered on other series sizes within the family.
• Filling Media: Glycerine standard (+20°F to +150°F); Silicone special order (-40°F/150°F).
• Dial Markings: psi & kPa

Safety and Standards Notes

A warning states that misuse may cause explosion and personal injury; users should read ANSI B40.1 before installation or use. Glycerine can combine with strong oxidizing agents including chlorine, nitric acid, and hydrogen peroxide to result in an explosion. Consult the factory for proper filling medium in hazardous service.

Key Product Differences

The Series NF402 is distinguished within the Weiss stainless steel industrial gauge family by its 4" case size with a bayonet ring and specific accuracy of 1% of span. It utilizes Type 316 Stainless Steel for both tube and socket, differentiating it from lower-range series (e.g., LF251) that may use Phosphor Bronze tubes or Brass sockets.

Compared to the liquid-filled Series LF402 family members which share similar dimensions but differ in fill status, the NF designation indicates a non-liquid filled configuration is not applicable here as this specific series description emphasizes "leakproof" and lists glycerine/silicone fills; however, the source document groups these under both Liquid Filled (LF) and Industrial Stainless Steel Cases (NF) headers. The NF402 specifically features a micro-adjustable pointer and safety glass window.

Other series sizes in this family include 2 1/2" (Series LF/NF25x), 6" (Series LF/NF60x). Accuracy varies by size: ±1.6% of span for 2 1/2", 1% of span for 4", and 1/2% of span for 6" gauges.