as i didn't have any stop valves in my house i thought i would add them while i was changing the taps in my kitchen. so i drained my water tank in the loft by turning the stop valve at the top of it. i've added the valves under my sink and connected the pipes back together. i turned the valve on the tank to re-fill it but i don't have any cold water coming through the pipes. a friend mentioned to me it could be an airlock, so i looked for advice on how to get rid of it. i connected my pipes to have the hot feed go up the cold water pipe, i did this for what felt like forever ( maybe half an hour ) but still no cold water. can anyone please help me.....i cant even flush the loo 
