Gurgling water dripping sound coming from basement trap drai

[Tennis12]

Hi, Live in condo. In my crawlspace where my drain is close to my furnace water is dripping inside drain constantly in last 2 months-echo into upstairs. Tried pouring water in drain/trap in case stuck-no result. When I turn off my cold water shut-off-dripping stops and water off-when I turn back on it immediately starts running into pipes-plastic- and dripping starts again. Drain below is close to my run-off pipe from furnace for A/C but A/C is off.
Any ideas? Tennis12

 

[Nige F]

Haven`t got a sccoby , me old china . UK forum

 

[HERTS P&D]

At first Nige I thought you were going to suggest to get Scooby-Doo to investigate.

Andy

 

[Nige F]

Nah - GHI , Ghost Hunters International