New Faucet installed in Kitchen sink. The cold water runs just fine but I keep getting little pieces of black stuff in the filter of the hot water line. The hot water will run fine for about 30 Seconds then slowly starts to slow down to the point that it barely comes out. This line also splits to the Dish Washer, that runs fine. I Can take the filter off the line and dig all of the black pieces out and it will do the same thing over again. The guy who installed it couldn't get the nut off of the old faucet so he cut it off, is there a chance something got down in the hot water line?
Most likely it is shavings and debris from the cutting the guy did into the waterline.
You should turn off the water supply valves and disconnect the water lines from the faucet but not from the valves ( do the cold even though it hasn’t given you problems just for peace of mind ).
Get a bucket and put the end of the supply lines that were attached to the faucet into the bucket and hold onto them while you open the valve and bleed the system for about a minute. ( Open the valves slowly there will be quite a bit of pressure)
Before you reattach the supply lines to the faucet open both the cold and the hot on the faucet, take the aerator out and try to blow backwards through the faucet to blow any debris that might still be left inside the faucet back out.
Reassemble the faucet reattach the supply lines and see how she goes.