I recently remodeled the kitchen and included a not-cheap fancy name-brand single lever faucet with the popular pull out spray feature. It was a bear to install but that's not my problem.
We now get very low water volume. It takes almost 10 minutes to fill one side of the double sink, about 30 seconds to fill a 2 quart pitcher, and almost as long to fill the coffee pot. Also, for hot water, it now takes well over a minute before it starts to get warm. This wasn't a problem with our old plumbing and I have adequate city water pressure.
The water column looks adequate because of the aerator but obviously it's mostly air. I figure I'm getting about 1 gallon per minute. I've checked elsewhere in the house, I get at least 5 gallons per minute at the garden hose (I checked when filling the swimming pool).
I used the existing supply pipes when installing the new fixture and volume wasn't an issue before.
Examining the pull-out sprayer, it appears that all the water must pass through a .25" OD pipe(no idea of the ID).This must be the problem!
In all honesty, my wife is thrilled with the new kitchen, it's just me(for now) noticing the problem.
I'm thinking there's no solution here but I would appreciate any suggestions.