Hello everyone I was wondering if you could help me solve an issue I'm having with air in my hot pipes. I had a positive head pump installed in the airing cupboard as shown in the picture but it would not start without putting the shower head in the bath to increase the pressure. After a month of doing that I changed the pump for a negative head one which has solved that problem but I don't think I'm getting the pressure out of it I should be and it continues to run for about 5 seconds after I have switched off the shower. It's also noiser than I think it should be. I have used all the existing pipe work installed by the plumbers. This morning I read up online to remove air in the system turn to cold and run for 5 mins with the pump off and the same for the hot water. Cold was fine but I noticed air coming through the hot every 4-5 seconds I could hear it working its way through the pipes and coming out of the shower hose which I had put down into the bath. It's only a small bit of air but it seems constant. It did it for the full 5 minutes of running the hot. Should I just keep doing this untill either the air stops or I drain all my hot water to cold and the air stops or will it not stop because I have another underlying problem? Any help would be great fully received.