Hard start capacitor sizing?

[jlb27537]

Hello,

What happens when a hard start capacitor that is larger than what the compressor needs is used.

Thanks Jim

[Mr Bill]

How did you come to that conclusion? did you look at the tonnage of the unit and then the HP rating of the Start Assist? I really don't know what it might do to the compressor, maybe kill more of the already dead start windings. Bottom line, I would say you need to match HP of the start assist with the rated HP of the compressor, don't just go by the tonnage of the unit, you need to go by the HP of the compressor.

[jlb27537]

Thank You Mr. Bill,

What prompted the question, in the Supco product line of hard start caps, the model SPP-8E is suggested for a 1-10HP compressor and uses a 189-227uf cap. The SPP-9E is suggested for a 1-5HP compressor and uses a 233-280uf cap.The SPP-10E is suggested for a 3-5HP compressor and uses a 270-324 cap.

Now if you had a 3.5 HP compressor, any of the above would work.

So my question is, IF you used a SPP-10E, and only needed a SPP-8E for the extra kick, what, if any, damage would be caused by using a higher capacity cap as used in the SPP-10E?

[hvacvegas]

I've seen a 1.5 ton unit with a hard start rated up to 5 tons. The whole unit rocked on startup.