Grundfos 99490916 ALPHA2 26-99F Variable Speed Circulator Pump

Product Overview

The Grundfos ALPHA2 26-99F is a high-efficiency, variable-speed circulator designed for modern hydronic heating systems. With an ECM motor, advanced AUTOADAPT functionality, and multiple pressure-control modes, the ALPHA2 automatically adjusts pump performance to match heating demand, improving comfort while reducing energy consumption. Its cast-iron housing, magnetite-resistant design, and integrated check valve make it a reliable and service-friendly choice for residential and light commercial installations.

Features & Benefits

• High-efficiency ECM motor for reduced energy consumption
• AUTOADAPT mode optimizes performance based on system demand
• Constant-pressure and proportional-pressure modes with 3 settings each
• Integrated check valve for simplified installation
• Magnetite-resistant internal design protects system components
• One-button operation with LED display for easy commissioning
• Durable cast iron housing (EN-GJL-150)
• Quiet operation with smooth variable-speed control
• Terminal box included for conduit connections

Specifications

Technical Performance
Head max: 32.48 ft
TF class: 110
Approvals: UL

Materials
Pump housing: Cast iron (EN 1561 EN-GJL-150)
Impeller: Composite

Installation Requirements
Ambient temperature: 32–131°F
Max operating pressure: 145.04 psi
Connection type: GF
Pipe connection: 1 1/4"
Pressure rating: PN 10
Port-to-port length: 6 1/2 in

Liquid Handling
Pumped liquid: Water
Temperature range: 14–203°F
Selected temperature: 140°F
Liquid density: 61.35 lb/ft³

Electrical Data
Power input: 3–120 W
Voltage: 115 V
Frequency: 60 Hz
Max current: 0.05–1.7 A
Enclosure class: IP42
Insulation class: F
Thermal protection: Electronic

General Information
Net weight: 7.71 lb
Gross weight: 8.47 lb
Shipping volume: 271 ft³
Country of origin: USA
HTS code: 8413.70.00.21

Installation Tips

• Use AUTOADAPT for optimal efficiency in most installations.
• Install with the motor shaft in the horizontal position.
• Flush piping to remove magnetite and debris before installation.
• Utilize the built-in check valve to prevent reverse flow.
• Select proportional pressure mode for TRV-based systems.
• Select constant pressure mode for baseboard and low-variation loops.

Frequently Asked Questions

What does AUTOADAPT do?
AUTOADAPT automatically adjusts pump output to meet heating demand.

Is this model good for radiant heating?
Yes, the ALPHA2 provides precise variable-speed control ideal for radiant and low-temperature systems.

Does it resist magnetite?
Yes, the internal design helps protect the pump from magnetite buildup.

Does it include a check valve?
Yes, the pump is supplied with a built-in check valve.

What is the liquid temperature range?
The pump can operate between 14°F and 203°F.

Technical Downloads:

• Grundfos 99490916: Specification Submittal