I plan on replacing my my home HVAC condenser fan motor, as well as the compressor contactor, and the capacitor.

The current condenser fan motor is a TradePro TP-C16-1SP2 which requires a 10 μF run capacitor, per the label:

TradePro TP-C16-1SP2 condenser fan motor

The replacement condenser fan motor will be a Rheem/Protech 51-100999-03 which requires a 3 μF /370 VAC capacitor, per the label:

Rheem/Protech 51-100999-03 condenser fan motor

Both fan motors are rated at 1075 RPM and 1/6 HP.

The compressor is a Copeland ZR32KA-PFV-130 scroll compressor which requires a 50 μF/370 VAC run capacitor, per the label:

Copeland ZR32KA-PFV-130 scroll compressor

Currently, the only capacitor I found when I removed the cover on the A/C unit outside was a Titan Pro TOC10 10 μF/370 VAC run capacitor. I believe this is what is known as a single capacitor rather than dual capacitor.

Titan Pro TOC10

It seems as though this is the proper capacitor to run the TradePro condenser fan motor. However, I don't see a capacitor for the compressor.

Here is an image of the schematic for the compressor and condensor assembly:

enter image description here

What capacitor should I use for the new condenser fan motor and compressor combination?

Edit: Okay, so I think I neglected to identify the start capacitor which I believe is pictured here:

enter image description here

If that is the start capacitor, then the wiring appears to be normal, and I can just get a start capacitor that matches the specs for the compressor (and of course, a run capacitor for the condenser motor).

  • That 10uf cap is wrong. I think we're missing some information such as a make/model and possibly a wiring schematic. A few more pictures of the overall unit would be nice too. You might have a setup for a three terminal "dual cap". A dual cap is just two capacitors in one case with a shared common terminal. One for the fan and one for the compressor. If it is setup for a dual cap, you should see an orphaned wire. If it was replaced, it's possible someone stuck that wire on a spare terminal. Find a schematic! It is also possible that the fan capacitor is located on the motor itself.
    – Mister Tea
    Aug 23, 2017 at 20:12
  • @MisterTea-Missing the make/model of what? I put the make/model of the condenser fan motor (which has the same specs as the current one), the compressor, and the capacitor. What am I missing?
    – user56530
    Aug 23, 2017 at 20:36
  • I will add a pic of the wiring and the schematic though.
    – user56530
    Aug 23, 2017 at 20:39
  • It seems like you may have to trace out the wiring or provide detailed photos of it... Aug 23, 2017 at 23:14
  • 1
    Caps normally are +-10% , a motor that requires a 10 will start in most cases with 8-12uf but if designed for 10 that will provide the best phase shift and start the motor With less stress on the system. Run caps will affect your monthly power bill if way out.
    – Ed Beal
    Aug 24, 2017 at 1:49

2 Answers 2


Buy a 50-3 dual capacitor. Titan part number TRCD503 is a good replacement. Just be sure to double check part numbers because manufactures offer both round and oval shapes. If it doesn't fit in that original mounting hole, you might need to buy a bracket for it and mount it yourself.

You can also leave the compressor capacitor in place and install a separate 3uF fan capacitor. It won't hurt the dual capacitor to have its fan terminal unused. Just be sure it's voltage rating is more than the line voltage so a 370 or greater volt rating is fine. Make sure the value is 3uF and the capacitor construction is of the film type.

My opinion: replace the compressor cap as well. Especially if the unit is 10+ years old.

If you add a separate capacitor, make a note on the units schematic for future reference with a service date.

By the way, that equipment grounding conductor (EGC) looks a little on the small side. Should be no smaller than 10 AWG for 30-60 amp circuits.


Since you aren’t replacing the compressor don’t worry about that capacitor. It has to be there somewhere or it wouldn’t run. The unit originally came with a dual run capacitor. When the condenser fan motor was replaced they took the wires off the dual capacitor and put them on the 10 micro farad capacitor. You will likely find a dual run capacitor with no wire to the fan side. Just leave the capacitor hooked to the compressor and buy a new 3 micro farad capacitor for the new motor. Edit. Looking at the picture. That is the dual run capacitor. The terminal that is missing the wire is where the fan wire went. The start cap was optional.

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