Thank you for your question, and I am sorry to hear that you are experiencing an issue with your Delta faucet. We do recommend to flush the valve body to make sure no debris is stuck inside that maybe causing the low flow.
To flush: first turn the water off at your water supply. Remove the handle, remove the sleeve assembly, unscrew the bonnet nut. Pull the cartridge assembly straight out. The cartridge can be cleaned by rinsing this out thoroughly in another sink. Once everything is removed, turn the water supply back on. This will flush the water straight through the open valve body. Keep this on for a good 30-45 seconds. Turn the water off and reinstall parts. If this does not solve the issue, the valve cartridge assembly may need to be replaced. If you should need further assistance, please contact us back.
Date published: 2018-08-07