Series 4270

Summary

Product Identification

The Armstrong Series 4270 are Motor Mounted Centrifugal Pumps.

Applications:

• Cooling towers
• HVAC
• General purpose

Operating Limits

• Max. flow (3600 rpm): 130 USgpm (8.2 L/s)
• Max. head (3600 rpm): 130 ft (39.6 m)
• Max. working pressure: 150 psig (1034 kPa)
• Max. operating temperature: 275°F (135°C)

Mechanical / Hydraulic

Key Features:

• Volute: Radially-split design allows in-line servicing. Tapped openings for venting, draining, and gauge connections.
• Impeller: High strength engineered resin or bronze impeller reduces axial thrust.
• Motor: Equipped with heavy-duty, permanently lubricated ball bearings. Designed to operate at 3600 rpm.
• Mechanical Seal: Self-lubricating, Type 21, with a carbon face rotating against a stationary ceramic seat.
• Adaptor: Aluminum die cast, with integral support foot.
• Shaft: Motor shaft extends through to the impeller, eliminating an intermediate bearing bracket for a close-coupled design.
• Back Pull-Out Design: Allows motor, bracket, and impeller to be withdrawn from the volute without breaking piping connections.

Technical Data:

• Suction size: 1¼", 1½", 2"
• Connections: All pump sizes are provided with NPT screwed connections.

Materials of Construction:

• Volute: Cast iron
• Volute cap screws: Steel
• Impeller: PEI resin or Bronze
• Mechanical Seal (Type 21):
  • Insert: Carbon
  • Seat: Ceramic
  • Bellows: Viton
  • L-cup: Viton
  • Retainer: Stainless steel
  • Spring: Stainless steel
• Motor/bracket: Aluminum
• Faceplate: Stainless steel
• Shaft: 416 stainless steel (from typical specifications)

Optional Equipment:

• Seal Flushline
• Bronze fitted pump

Performance Curves

Performance curves are available for various pump sizes (1.25 × 1 × 5, 1.5 × 1.25 × 5.5, 2 × 1.5 × 5.5) at both 1800 rpm and 3600 rpm. These curves illustrate head vs. flow, NPSHR, and efficiency for different impeller diameters and motor horsepower ratings (0.333 hp, 0.5 hp, 0.75 hp, 1 hp, 1.5 hp, 2 hp, 3 hp, 5 hp). See the official PDF for exact tabulated values and graphical representations.

Dimensions

Dimensions are provided in inches (mm) for the following pump models:

• 1¼" × 1"
• 1½" × 1¼"
• 2" × 1½"

Motor dimensions (L) are also provided for various horsepower ratings:

• ½, ¾ hp
• 1 hp
• 1½ hp
• 2, 3 hp
• 5 hp

See the official PDF for exact tabulated values and dimensional drawings.

---

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

Official datasheet (PDF)

Lenntech datasheet mirror