OS X Yosemite - TCP/IP issues when using manual IP
Looks like I am affected by the issue posted here. The proposed solution of adding a new default route works. If anybody else, has a better solution, where I don't have to do that everytime - when I switch between DHCP and Manual - I would love to try it. Thanks

Solution posted there is to add a default route to the router IP

sudo route add default 192.168.x.x