Quick answer: For the Hayward HeatPro (HP21003T, HP2100TCO3T, HP11003T, HP6003T, HP21405T), the Hayward HPX11024154 60uF Capacitor is the correct compressor-side OEM part. Pentair UltraTemp models (70 through 140HC) use the Pentair 473731Z 80/7.5 MFD Dual Run Capacitor, which covers both the compressor and fan motor in one part. AquaCal and Gulfstream heat pumps (the HE-RA lineup and older SQ-series) commonly use the AquaCal ECS0247 80/440V Compressor Run Capacitor. All three are electrical components specific to heat-pump models — gas heaters don’t have a compressor capacitor at all, since they have no refrigerant circuit to run.
A capacitor is a cheap part with an outsized symptom: a $30-$160 component failing can make an otherwise-healthy heat pump look like it needs a full compressor replacement, which typically runs into four figures. According to the parts-lifespan research behind our own pool heater parts guide, electrical components like capacitors and start relays fail well before the compressor or heat exchanger itself, especially in hot, humid climates where a capacitor’s internal chemistry degrades faster. Before assuming the worst, it’s worth ruling this part out first.
Pool heat pump capacitors at a glance
| Capacitor | Fits | Rating | Price |
|---|---|---|---|
| Hayward HPX11024154 | HP21003T, HP2100TCO3T, HP11003T, HP6003T | 60uF, 370V | $28-$55 |
| Pentair 473731Z | UltraTemp 70-140HC (NA/LP) | 80/7.5 MFD, 440V (dual) | $90-$160 |
| AquaCal ECS0247 | Gulfstream HE-RA lineup, SQ-series | 80uF, 440V | $70-$160 |
1. Hayward HPX11024154 — For HP21003T, HP2100TCO3T, HP11003T & HP6003T
Hayward HPX11024154 60uF Compressor Capacitor
- Runs the compressor motor specifically — Hayward's fan motor uses a separate, smaller-rated capacitor (HPX11024151, 7.5uF), so confirm which motor is actually failing before ordering.
- Prices swing unusually wide between retailers for this exact part, from under $30 on sale to over $50 at full list — worth comparing two or three listings before buying.
- Mounts with two screws and spade-terminal wire connectors inside the compressor compartment, not the water-side plumbing — no draining or gas work required.
- A compressor that hums but doesn't spin up, especially right after a breaker reset, is the classic symptom of this capacitor weakening with age.
Always discharge a capacitor safely before touching its terminals, even with the unit unplugged — it can hold a stored charge for minutes after power is cut.
2. Pentair 473731Z — For UltraTemp 70-140HC
Pentair 473731Z 80/7.5 MFD Dual Run Capacitor
- A dual-rated capacitor that runs both the compressor (80 MFD) and fan motor (7.5 MFD) from one part, which is why it costs more than Hayward's single-motor capacitor above.
- 3-phase UltraTemp models (120C and 140C) use a different part number (473154) — check your rating plate before ordering if your install uses 3-phase power.
- Pentair also sells a separate hard-start capacitor kit (476422Z) for UltraTemp units that struggle to start in very hot ambient temperatures, a slightly different fix than a worn run capacitor.
- Comes with the mounting bracket already attached, matching the factory-original setup rather than a bare capacitor you have to re-bracket yourself.
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3. AquaCal ECS0247 — For Gulfstream HE-RA & SQ-Series
AquaCal ECS0247 80/440V Compressor Run Capacitor
- AquaCal (Gulfstream's parent brand since Pentair's acquisition) lists several capacitor variants across its lineup by MFD rating — 40, 45, 50, 55, 60, 70, and 80uF versions all exist for different compressor sizes, so this 80uF part fits the larger HE125-RA/HE150-RA-class units specifically.
- A separate, smaller fan capacitor (ECS0044, 5uF) runs the fan motor independently on these units, similar to Hayward's split compressor/fan design.
- Our [Gulfstream heat pump review](/best/best-gulfstream-pool-heat-pump/) covers the HE-RA lineup's other common wear parts if the capacitor turns out not to be the issue.
- AquaCal's own tech support line can confirm the exact part for older SQ-series units, since capacitor ratings changed more than once as the compressor lineup evolved over the years.
How to confirm it’s the capacitor before you buy
Listen and look first: a compressor that hums for a few seconds without spinning up, a fan that turns visibly slower than it used to, or a breaker that trips right at start-up are all classic capacitor symptoms, and a bulging or leaking capacitor case is a dead giveaway with no diagnosis needed. If the compressor doesn’t hum at all, or a fresh capacitor still trips the breaker instantly, the problem is more likely the compressor itself or its start relay — both pricier repairs where the 50% rule from our repair cost guide is worth applying before you sink more money into an older unit. For the full troubleshooting order across every heater type, see our pool heater not heating guide.
Match the exact MFD rating and voltage to your model, not just the brand — a capacitor rated too low for its motor will fail again quickly, and one rated too high can strain the motor windings. The compressor compartment’s rating plate or the original capacitor’s own printed label is the source of truth here.
The bottom line
A capacitor is one of the cheapest parts on a pool heat pump and one of the most commonly misdiagnosed, since its failure symptoms — a humming compressor, a slow fan, a tripped breaker — mimic much more expensive problems. The Hayward HPX11024154, Pentair 473731Z, and AquaCal ECS0247 each cover their brand’s mainstream heat-pump lineup at roughly $28-$160 in parts, cheap insurance against paying a technician’s diagnostic fee to rule in a part you could have swapped yourself. If the capacitor is one of several aging components failing at once, our pool heater lifespan guide can help you weigh repair against replacing the whole unit.