AO Smith and Century motors are the dominant generic replacement motors used across Hayward, Pentair, Sta-Rite, Jandy, and Waterway pumps — most major pool pump brands don’t actually manufacture their own motors. Matching by frame size, service factor HP, and voltage gets you a correct cross-reference regardless of what brand name was on your original pump.
Why AO Smith and Century Show Up on So Many Pumps
Here’s something that confuses a lot of pool owners: your Hayward, Pentair, or Sta-Rite pump almost certainly has an AO Smith or Century motor inside it, even though the pump is branded otherwise. These two companies (now both under the Regal Rexnord/Century umbrella after various corporate mergers) are OEM motor suppliers to the entire pool industry. When your pump motor fails, you don’t need to find a “Hayward motor” — you need to find the correct AO Smith or Century motor that matches your specs, which is often cheaper than buying through the pump brand directly.
Overview of AO Smith pool pump motors as the OEM supplier behind most major pool pump brands.
How to Cross-Reference Your Motor
Read these specs off your existing motor label — this works regardless of what pump brand is stamped on the housing:
- Service Factor HP (SF HP) — the higher number on the label, not the base HP rating
- Frame size — 48Y or 56Y, determines physical bolt pattern and shaft height
- Voltage — 115V, 230V, or dual-voltage
- RPM — almost always 3450 for single-speed
- Shaft type — threaded or keyed, determines how the impeller attaches
With these five specs, any AO Smith or Century catalog (available through RepairClinic, PoolSupplyWorld, or directly from these manufacturers’ distributor sites) will surface the correct cross-reference part number, regardless of what pump brand you originally had.
UST and USQ Series — What the Letters Mean
AO Smith motors commonly use model codes like UST1102 or USQ1152. UST generally indicates a threaded shaft (common on Hayward-style pumps), USQ indicates a square-flange or different mounting configuration. The numbers following indicate horsepower and frame variations. If you’re replacing a motor and see one of these codes on the old unit, search that exact code first — it’s often the fastest path to an exact match.
Century Motors — Frame Compatibility
Century motors (HSQ, SQ, and other series) are similarly cross-compatible with Hayward, Pentair, Sta-Rite, and most other 48Y/56Y frame pumps. The Century brand and AO Smith are now part of the same parent company in many cases, so their catalogs often overlap significantly in coverage.
Installing a Cross-Referenced Motor
Once you’ve confirmed frame size, SF HP, and voltage match, installation follows the same procedure as any motor swap — disconnect wiring (photograph first), remove through-bolts, separate from wet end, transfer the impeller and install a new shaft seal, reassemble. See our full motor replacement guide for the complete step-by-step process — it applies identically whether you’re installing an AO Smith, Century, or any other brand replacement motor.
Price Advantage of Generic Replacement Motors
Buying an AO Smith or Century motor directly (rather than a “genuine Hayward replacement motor” at a markup) commonly saves 20–40% for an identical or functionally identical part, since you’re buying from the actual manufacturer rather than through the pump brand’s parts markup. Always verify the cross-reference carefully — the savings only matter if the motor is genuinely correct for your application.
Frequently Asked Questions
Is an AO Smith motor as good as a genuine Hayward replacement motor?
In most cases it IS the genuine motor — Hayward and most other pool pump brands source their motors from AO Smith or Century rather than manufacturing in-house. Buying directly from AO Smith or Century at the correct cross-reference spec gets you the identical component for less money.
How do I know if I need a 48Y or 56Y frame motor?
Check your existing motor label — frame size is listed directly. If the label is illegible, measure the motor: 56Y frame motors are physically larger in diameter than 48Y. Never guess; an incorrect frame size won’t bolt up to your wet end.
What does UST mean on an AO Smith motor model number?
UST generally indicates the shaft and mounting configuration used on many Hayward-compatible pumps. The specific letters and numbers in AO Smith model codes encode frame, HP, and shaft type — always cross-reference against your old motor’s exact specs rather than just matching the prefix.
Can I buy an AO Smith motor without knowing my pump brand?
Yes — that’s the whole point of cross-referencing by specs (frame, SF HP, voltage, shaft type) rather than by pump brand name. The pump brand on the housing is often irrelevant to motor selection.
How long do AO Smith and Century motors typically last?
8–12 years with proper maintenance, similar to any quality pool pump motor in this class. Shaft seal maintenance (preventing water intrusion into the motor) is the biggest factor in actual lifespan regardless of which of these two brands you choose.