Toby the Apartment Manager

Toby is the apartment manager in Highgate Towers. He also does minor repairs. Today, he has to do a different small repair in 4 different apartments.
Use the clues below to determine what he has to do in which apartment:

1. He has to tighten a doorknob but not in 2G or 4A

2. He has to replace a shower curtain rod in 3C

3. He has to fix a faucet but not in 1B

4. Neither 4A not 1B is the apartment where he has to rehang the door.