We had to have the mains connection pipe replaced due to leak. While this was being done and and the water was shut off, someone turned on the taps on the bathroom sink. Now when the pipe replacement job has been finished, water was turned on but the water flow in bathroom at the sink is very slow almost a trickle. I left the tap on for a long time, and it is four days now, I do not seem to be able to remove the AIR LOCK that has occured. Can some one help??