Any way to guess or measure the HP of a well pump without fishing it out?

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xenxes

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The house we bought has a windmill+electric well pump combo, but the previous owner never connected the electric pump to a control box.

Because it's attached to the bottom of a windmill pump assembly (of 100+ continuous feet of PVC with the pump cable taped to it), it's impossible to fish the pump out for visual inspection without destroying the PVC and removing all the pump rods.

According to the previous owner, the pump sits at about ~100ft, and is less than 2HP but he doesn't remember exactly and I can't track down a record of the install. The gauge of the pump cable is 14 AWG stranded copper (yellow, red, and black, so requiring the control box type).

I'm guessing it's a pump that works with a Franklin box because that's the type the installer used on the other well on the property. Looking at the voltage drop calculator of 14 AWG over 100 ft, I'm guessing 1.5HP is the maximum possibility (11.5A)? So the options are likely 3/4 HP, 1 HP, or 1.5 HP.

Today I tried hooking up a 1 HP Franklin QD Control Box (9.8 A), which wasn't it. The symptoms are: powers on for a second and pumps water, then turns off for about 20 seconds, and restarts again. Capacitor feels warm. Would it likely do this if it's underpowered or overpowered? Deciding whether to try the 3/4 HP or 1.5 HP next.

I'm probably being dumb about this, but this is the only thing I can think of to do without breaking and removing the entire windmill assembly?
 

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Valveman

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If it is a 1.5HP it will need a running capacitor. You can always use a larger box on a smaller pump but not the other way around. Try a larger box and check the amps when running as amps are the indicator for horsepower.
 
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