Series 4300

Summary

Product identification

The Armstrong Series 4300 are Split Coupled Vertical In-Line Pumps, described as the "Best Commercial HVAC Pump Design Available Since 1969".

Operating limits

• Flow Range: In excess of 30,000 USgpm (1,900 L/s).
• Pressure/Temperature:
  • Cast Iron casing with ANSI-125/PN16 flanges: Up to 175 psig (12 bar) at 150°F (65°C).
  • Ductile Iron casing with ANSI-250/PN25 flanges: Up to 375 psig (25 bar) at 150°F (65°C).
  • Higher temperatures are possible at lower pressures. Refer to the official PDF for detailed pressure/temperature curves and mechanical seal limitations (File No: 43.50).

Mechanical / hydraulic

The Series 4300 pumps are single-stage, single or double suction type, designed for vertical in-line installation as integral components of pipework. This eliminates the need for inertia bases, flexible pipe connectors, field grouting, and alignment.

Design Features

• Coupling: Axially split, spacer type rigid coupling made of lightweight high tensile aluminum. Permits seal maintenance without disturbing pump or motor.
• Motor Connection: Heavy cylindrical bracket with 360° register provides a rigid union of pump and motor.
• Shaft Tolerances:
  • Motor shaft run-out limited to 0.001” (0.025 mm) TIR (Total Indicator Reading).
  • Shaft deflection at mechanical seal limited to 0.002” (0.05 mm) TIR.
• Impeller: Bronze, fully enclosed type, dynamically balanced. Two-plane balancing is required where the installed impeller diameter is less than 6 times the impeller width.
• Volute: Radially split with equal suction and discharge flange sizes. Includes separate drilled and tapped openings for gauge, flush, and drain connections. Liberal inlet passageways and straightening vanes provide optimum suction performance.
• Casing Gasket: Confined casing gasket for stringent industrial temperature and pressure applications.
• Seal Chamber: Features a lower seal chamber throttle bushing to ensure positive cooling and lubrication for seals.
• Maintenance: Designed for easy access to mechanical seal components by removing the split spacer coupling, allowing servicing without disturbing other pump components or motor connection. The rigid coupling ensures factory alignment upon re-installation. No pump bearings to service.

Sealing Arrangements

Two mechanical seal arrangements are available, both easily removable for servicing without removing the motor or pump from piping:

• Outside Balanced Mechanical Seal: Multi-spring balanced type with premium quality, easiest to remove. Components include Stainless Steel, Viton secondary seal, carbon rotating face, and silicon carbide stationary seat. Provided with a 316 stainless steel gland plate and factory-installed flush line with manual vent.
• Inside Unbalanced Mechanical Seal: Provides an economical alternative.

Optional Seal Flush Line Accessories

• Cartridge Filter: A 50 micron cartridge filter and sight flow indicator can be supplied in the flush line.
• Sediment Separator: A maintenance-free sediment separator with sight flow indicator can be supplied, requiring pump differential pressures exceeding 70 ft/30 psig/200 kPa for effective operation.

Materials of Construction

• Volute: Cast Iron (ASTM A48 class 30) or Ductile Iron (ASTM A536 grade 65-45-12).
• Impeller: Cast Bronze (ASTM B584 grade C84400), All Bronze, or Bronze Fitted. Zero Lead Bronze is used for potable/drinking water applications.
• Pump Shaft: Stainless Steel (ASTM A276 type 303, type 316).
• Coupling: High Tensile Aluminum Bar.
• Gasket: Fiber or Neoprene.
• Gland Plate: Cast Bronze or Stainless Steel (ASTM A276 type 316).
• Other components (e.g., capscrews, washers, nuts, adapter parts, motor shaft, stuffing box cover) utilize Steel, Brass, or various Stainless Steel grades.

See the official PDF for exact tabulated values and full material construction legend.

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Disclaimer: This summary is based on extracted text and may not include all figures, footnotes, or the latest revisions from the complete OEM PDF datasheet. Contractual data must always match the specific OEM PDF revision used on the project.

Official datasheet (PDF)

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