Hello, tried to post this question in /r/plumbing but my account is too shiny...2nd floor bathroom. Brand new: shutoff valves to toilet, basin hot, basin cold. New supply lines to the above. New centerset basin faucet. New toilet fill valve.Problem: Only a trickle of water from the basin cold faucet except when the toilet is refilling. When the toilet is refilling, the basin cold flow is strong and 100%. The instant the toilet fill valve trips (toilet tank is full) the flow to the basin cold is reduced to a trickle abruptly (with water hammer).I have drained and flushed the supply lines to purge debris and air locks. Didn't fix my problems. If the toilet shutoff valve is closed (to isolate the antisiphon attributes of the new fillvalve (black magic at this stage), the problem persists.The shower and tub cold flow is normal. The hot water at all outlets is normal.Water pressure is 62 PSI.Edit: Mentioned this important detail in the post which got rejected but omitted it here: I replaced everything because this issue cropped up before I had initially replaced a leaky toilet fill valve. Until I could get around to buying a new fill valve, I was using the toilet shut off valve to prevent wasting of water from an overfilled toilet tank. That was when I noticed that the old basin faucet wasn't working...spider to catch the fly...fuck it, just replace everything.-> problem still exists.Any clues? via /r/DIY http://ift.tt/2wNt0Tx
