Sounds like you have trash in hot side of value or cartridge...shut off water remove cartridge....check for trash....turn on water slowly to clear lines...may take 2 people to do this 1 to turn water on while other sees if water comes out both ports in value....look in cartridge to see if any clog....if you can get a bucket of soapy water before hand and wash cartridge under soapy water...reinstall and check....if water comes out off both ports without cartridge in...when you reinstall after cleaning it still no flow...you may need new cartridge,,,good luck