I've been trying to find an air vent valve in the Toronto area but I haven't been able to find a supplier who is familiar with these, and more importantly help me choose the right one for my application. I'm looking to build a water drain back system where a lake submersible pump (10 GPM) will push water up a 1" poly pipe to a dwelling where there is a check valve. Once the pressure is reached (approx 40 psi) the check valve shuts and the water in the pipe recedes to the lake. The water in the dwelling side of the check valve stays inside because the check valve is closed. I need an air vent valve that will allows the air to escape as the submersible pump pushes the water towards the check valve. Once the check valve closes, I need the air vent valve to open again under negative pressure to allow air into the pipe to allow the water to drain back to the lake. As I say, I could not find a supplier in the Toronto area (or anywhere else for that matter) that has something like this. However, I did find that GA industries make such an animal (actually many types of them), but upon contacting them they say that their products are commercial and not suited to a residential application. Any ideas anyone where I can get an air vent valve that does this (Toronto or anywhere else), and what do I ask for?