Partial Mash Sparge Question

I've been sparging 2 quarts at 170 degrees for a 5 gallon recipe. Is that the right amount of water? Should I use more?

For how much grain?

In one kit I had a total of 15 lbs of grain. In another kit I had a total of 17.5 lbs. My confusion is that the instructions are always the same 2 quarts at 170 degrees. I've also missed my target OG a couple of times. Was wondering if maybe I haven't been sparging with enough water.

Still being a noob with only 25 gallons under my belt I'm not confident on when to increase/decrease.

Can you post a link to the kits or did you buy them locally?

That's more of an all grain batch than partial. I mean, yes, technically if you add ANY malt extract to it it's a "partial" mash but we're on the verge of requiring a new term like "mostly mash".

A 2 quart sparge in 15 pounds of grain is like pissing on a forrest fire.

Are you sure the directions don't say 2 quarts PER POUND?

For example, you might mash 15 pounds with 5 gallons of water. You'd get about 3 gallons of runnings out of that. A 2 quart sparge would only get you 3.5 gallons total.
Again, since these are all grain type grain bills here, you should be deriving at least 6-7 gallons of preboil wort. Therefore, the sparge would be closer to 3-4 GALLONS.

If you can't handle 6-7 gallons of wort in your kettle, you'll want to get some true partial mash kits that use 2-5 pounds of grain and 3-6 pounds of malt extract. That way you can be comfortable with 2-3 gallons of preboil.

That;s definitely not enough for a sparge, sounds closer to a mash out. IIRC, the amount of sparge water is essentially supposed to be Batch Size + Evaporation Loss - First Runnings. So for a 15lb batch, it'd be something like 5gal + 1gal/hr boil - 0.85* 15 = about 3gals