With that cartridge out and water flowing from that brass valve,
did you flush your water lines without that cartridge in before putting it to use?
If you didn't, that's why it's not working, and dirt/debri has clogged the cartridge.
It can be cleaned but if it's in the balancing spool you'll have to disassemble the cartridge.
What type water lines are in your home, and what method did you use to join piping back together...?