A.O. Smith B2858 Replacement

Verified specifications

Full-rated: match total HP (THP = label HP × service factor) to the pump's requirements, and confirm full-rated vs up-rated before swapping.

56Y fitment: square-flange mount — the Pentair WhisperFlo / Challenger / Pinnacle and Sta-Rite Max-E-Pro / Max-E-Glas / Dura-Glas class.

Single-speed and CA/NY: California and New York require variable-speed replacement motors (Title 20) for most pool pump replacements; see the VGreen Evo line.

Shaft seal: replace the pump shaft seal whenever the motor is changed — a leaking seal is the #1 killer of new pool pump motors.

Dual branding: this stock number is sold interchangeably as A.O. Smith and Century — Regal Rexnord's aftermarket motor brand. Same motor, same specs; see the Century B2858 page.

Older variant merged: the B849 is the 230V-only older variant of this motor (10.0A) — near-identical; match THP.

Replacement motor for Pentair Challenger, WhisperFlo WF-6, and Pinnacle pumps.

Confirming the right replacement

Before we quote, compare these fields on your failed motor's nameplate. If any of them differ, send us a photo of the nameplate and we'll match it exactly rather than guessing:

• Full model number — including any suffix letters
• HP, RPM, and voltage
• Frame size (e.g. 284T) and enclosure (TEFC, ODP, etc.)
• Full-load amps

Other A.O. Smith models

• More A.O. Smith modelsBrowse every A.O. Smith model page we quote
• Century B2858Same stock number under Century branding — identical motor