Quick answer: For a Hayward HeatPro HP21004T through HP21404T (the pre-titanium generation), the OEM fan motor is Hayward SMX300055036 (1/3 HP, 825 RPM), running $299.95-$365.72. Pentair UltraTemp 140/140HC uses Pentair 473785 Fan Motor with Acorn Nut Kit, $367.16-$391.99. AquaCal/Gulfstream SQ-series units use AquaCal ECS0095 (SQ166, 2-speed) or ECS0110 (SQ121/T-115), and the newer R410A SQ140R/160R/200R line takes the AquaCal STK0080 fan motor kit. Raypak Crosswind V 4550 through 8550 heat pumps use Raypak 100-10000638, $293.99-$390.99. Before buying any of these, rule out a failed run capacitor first — a hum-without-spin symptom is far more often the cheaper part.
Fan motor replacement is a heat-pump-only repair — gas heaters like Raypak’s Digital line or Hayward’s Universal H-Series don’t have an evaporator coil to pull air across, so they have no equivalent part. According to Angi’s cost data for HVAC-style fan motor swaps, a professional replacement typically runs $350-$700 installed, and a properly maintained motor usually lasts 5-7 years before bearing wear or winding failure takes it out. Below are the real OEM part numbers by brand, current retailer prices as of September 2026, and the one honesty-hook worth knowing before you order: the most common “dead fan” complaint isn’t the motor at all.
Pool heat pump fan motors at a glance
| Fan motor | Fits | Spec | Price |
|---|---|---|---|
| Hayward SMX300055036 | HP21004T-HP21404T, HP31154T, HP31204T, Summit XL | 1/3 HP, 825 RPM | $299.95-$365.72 |
| Pentair 473785 | UltraTemp 140/140HC | Fan motor + acorn nut kit | $367.16-$391.99 |
| AquaCal ECS0095 | Gulfstream/AquaCal SQ166 | 2-speed, 650/825 RPM | ~$209 |
| AquaCal ECS0110 | Gulfstream/AquaCal SQ121, T-115 | 1/3 HP, 820 RPM | Price varies by retailer |
| AquaCal STK0080 | SQ140R/160R/200R (R410A line) | Fan motor kit | Quote-only, not publicly listed |
| Raypak 100-10000638 | Crosswind V 4550, 5550, 6550, 8550 | — | $293.99-$390.99 |
1. Hayward SMX300055036 — For HeatPro HP21004T-HP21404T
Hayward SMX300055036 HeatPro Fan Motor, 1/3 HP
- This is the confirmed OEM fan motor for Hayward's pre-titanium HeatPro line, the generation this site tracked as discontinued and superseded by the titanium-MCHX HP21405T in our 08-28 heat exchanger correction.
- We could not independently confirm a distinct standalone fan motor part number for the newer HP21405T/HP21205T/HP21105T MCHX line in public retailer catalogs as of this writing — if your heat pump is one of those current-generation models, confirm the correct part with a Hayward dealer rather than assume SMX300055036 carries over, and check whether it's still under Hayward's warranty before buying anything.
- Requires removing the top fan grille/shroud to access the motor and blade mounting bolts — see our control panel guide for the same cabinet-access pattern.
2. Pentair 473785 — For UltraTemp 140/140HC
Pentair 473785 Fan Motor with Acorn Nut Kit
- Retailers consistently list this part for the UltraTemp 140/140HC; we found no separately-numbered part confirmed for the smaller UltraTemp 110 specifically, so match your model's rating plate before ordering rather than assuming the 140's part fits.
- The most expensive fan motor in this roundup, in line with UltraTemp's position as Pentair's premium heat pump — see our best pool heat pump guide for how UltraTemp's COP compares to Hayward HeatPro and Gulfstream at the full-unit level.
- Ships with the acorn nut that secures the fan blade to the motor shaft, so there's no separate hardware to source.
Want the part in hand before your pool has a chance to cool off? Try Amazon Prime free for 30 days and get it delivered in two days.
3. AquaCal/Gulfstream ECS0095, ECS0110 & STK0080 — For SQ-Series
AquaCal ECS0095 / ECS0110 / STK0080 Fan Motors
- AquaCal's SQ-series is the same manufacturing line behind the Gulfstream HE-RA models this site covers separately under Pentair's branding — the ECS-prefixed part numbers are the same family referenced in our capacitor guide's AquaCal pick.
- ECS0095 is a 2-speed motor (650/825 RPM) for the SQ166, priced around $209 at the retailers we checked; ECS0110 fits the smaller SQ121 and T-115 models but pricing varied enough across listings that we can't quote a reliable range.
- The current R410A-refrigerant SQ140R/160R/200R generation uses a different fan motor kit, STK0080 — we found it listed as compatible but without a consistent public price, so expect to request a quote from a pool-parts retailer rather than finding a fixed sticker price online.
- Confirm your exact SQ model number and refrigerant type (R410A vs. older) on the unit's rating plate before ordering — AquaCal has sold several SQ generations with different motor specs.
4. Raypak 100-10000638 — For Crosswind V 4550-8550
Raypak 100-10000638 Crosswind V Fan Motor
- Covers the full Crosswind V range that replaced the discontinued R8450ti, the same model-supersession this site documented sitewide across 10 pages in our 09-07 GEO correction.
- Because the Crosswind V is Raypak's current heat pump generation, this part number should stay valid without the "confirm it still fits" caveat that applies to Hayward's older HeatPro line above.
- Priced in the same $290-$390 band as the Pentair and Hayward fan motors above, despite the Crosswind V's higher COP rating and built-in Wi-Fi — the fan motor itself isn't where that premium efficiency comes from.
Rule out the capacitor first
Before ordering any fan motor, listen for what the unit is actually doing. A heat pump that hums or buzzes but the fan blade never turns is the textbook symptom of a failed run capacitor, not a failed motor — the capacitor delivers the extra electrical push an AC motor needs to start spinning, and a motor with a bad capacitor will sit there drawing power and heating up without moving at all. That’s a cheaper, easier fix; see our capacitor replacement guide before assuming the motor itself has failed. A genuinely bad motor usually announces itself differently: a seized or grinding bearing, a burning-insulation smell, or a blade that’s visibly jammed by leaves or debris that fell into the cabinet rather than an electrical fault at all — worth a quick visual check before ordering either part.
The bottom line
Fan motors are a heat-pump-specific part — Hayward HeatPro, Pentair UltraTemp, AquaCal/Gulfstream, and Raypak Crosswind V owners are the only ones who’ll ever need one, since gas heaters don’t have an evaporator fan at all. Prices cluster in the $290-$390 range across every current-generation brand here, with AquaCal’s older SQ166 running a bit cheaper at around $209. Before spending that money, confirm it’s actually the motor and not the far cheaper capacitor causing the hum-without-spin symptom, and if your heat pump is only a few years old, check the warranty before buying either part yourself.
Sources: Inyopools — Hayward SMX300055036 HeatPro Fan Motor, Poolweb — Pentair 473785 UltraTemp Fan Motor, PST Pool Supplies — AquaCal ECS0095/ECS0110 Fan Motors, Poolzoom — Raypak 100-10000638 Crosswind V Fan Motor, Angi — HVAC Fan Motor Replacement Cost