Time: 20–30 minutes. Skill: homeowner-comfortable with a screwdriver and able to isolate the circuit at the breaker. Cost: the price of one replacement capacitor (NZD incl GST).
Is it really the capacitor? Onga symptoms to watch
Onga pumps are everywhere on New Zealand pools, and the Pantera and PPP ranges in particular have a reputation for soldiering on for years. So when one suddenly refuses to start, owners often assume the worst and price up a whole new pump. Before you do that, listen to it: a buzzing or humming motor that won’t turn, a pump that trips out under load, or one that only spins after you flick the back fan by hand are all classic signs of a failed run capacitor — a cheap part, not a dead motor.
Replacing it yourself is straightforward with basic tools, as long as you follow the safety routine below to the letter.
Stop — make it safe before you start
Capacitors hold a serious charge long after the power is off, so never skip these steps.
- Isolate the supply at the breaker or the pump isolator before anything else. Switching off at the pump alone is not enough.
- Discharge the capacitor by bridging both terminals with a bleed resistor (around 10–20 kΩ, 5 W) or a proper capacitor discharge tool — a bare insulated-handle screwdriver across the terminals also drains it but sparks violently and can pit the terminals, so use that only as a last resort. This safely bleeds off the stored charge — a charged capacitor can bite hard.
- Under NZ rules, fixed mains wiring must be done by a licensed electrician. If your Onga is hard-wired into the switchboard or you’re unsure, call one in.
Where Onga hides the capacitor
On Pantera pumps the capacitor is typically clamped on top of the motor under a clip-off plastic cover or terminal hump at the rear. On the PPP (and similar pressure/booster builds) it can sit in a smaller terminal box, sometimes beside the wiring connections rather than on top. Either way it’s a cylindrical can with two or three spade terminals.
What you’ll need
- The replacement run capacitor — match the µF (within ±5%) and equal-or-higher voltage to the one fitted now.
- Phillips and flat screwdrivers.
- An insulated screwdriver, or a 10–20 kΩ bleed resistor with insulated leads, to discharge the old capacitor safely.
- A multimeter, if you want to confirm the diagnosis before swapping.
- Your phone — to photograph the wiring before disconnecting anything.
Steps
1. Kill the power
At the breaker/isolator and try to start the pump to confirm it’s truly dead.
2. Discharge the capacitor
— after a minute, short the terminals with a bleed resistor or a proper discharge tool (a bare insulated screwdriver also works but sparks — last resort) to release any stored charge before touching anything.
3. Remove the cover
— pop off the capacitor cover or open the terminal hump/box to expose the can.
4. Take a photo of the wiring
And the terminal positions so reassembly is foolproof.
5. Read the rating off the old cap
— note the printed µF and voltage. Many single-phase pool pumps fall in the rough 20–50µF range at 400–450V, but always confirm from your own capacitor or the motor nameplate, because the wrong value can cook the motor.
6. Unclip and unplug
The old capacitor — release the clamp and gently pull off the spade connectors.
7. Install the new capacitor
With the same µF and voltage, pushing each spade firmly onto its matching terminal, then refit the clamp.
8. Refit the cover/box
And check no wires are trapped or stretched.
9. Power up and test
— restore the supply and switch on. A healthy swap gives an instant, quiet start. If it still won’t go, isolate again and recheck.
Picking the correct replacement
Three things must match: the µF value, the voltage rating, and the can size/terminal style. You can go up in voltage but never change the µF. If your old capacitor is readable, copy its numbers exactly. If it’s blown or the print is gone, use the motor nameplate or our find-your-capacitor wizard. See compatible parts in our pump capacitor range or the pool capacitor shop. Browse all Onga pump capacitors by model to match your exact unit.
Onga-specific tips
- PPP and booster units can run smaller caps than a big Pantera filtration pump — don’t assume one Onga cap fits all.
- Check the spade connectors aren’t corroded; a dodgy connection can mimic a dead capacitor.
- If the motor smells scorched or the windings are discoloured, the capacitor may be a symptom rather than the cause — get it checked.
Find your Onga capacitor and order
Unsure of the value? Our find-your-capacitor wizard takes the guesswork out, or jump straight to the pool capacitor shop and the full pump capacitor range.
All orders ship tracked, around 2 weeks via NZ Post or courier, prices in NZD incl GST, backed by a 90-day DOA guarantee. Proudly NZ-owned.