Do not restrict air flow by using a valve in your air line. If you do this you will wear your vanes out quicker, higher pressure equals shorter life. You will also cause the motor to run hotter and use more electricity. I would avoid resticting the pump any more than necessary.
A better way is to intall a "T" in your plumbing coming from your pump. One branch goes to your aerator, the other branch goes to a ball valve that just vents out to the atmoshere. Then you can crack the valve just enough to bleed some air out of the line going to the aerator. This will actually lower the back pressure on your pump, it will take load off the motor and run it cooler, and it will make the pump last longer rather than shorter. Yes you are wasting some of the air you are pumping but it will actually be less energy waste than if you restrict your air line. You are just pumping some air from atmosphere back to atmosphere. If you don't have one alreay you should have a pressure gauge in the line going between your pump and the "T" I describe. This way you always know what pressure you are running and can tell if it exceeds the manufacturers pump rating.
I have a Thomas vane pump that is designed for a max pressure of 15 psi. I run two aerators with this pump so I have a valve in each line. I use the valves to adjust the flow so both aerators get about equal air. I always leave the one with the highest back pressure wide open and restrict the other one down to even the flow out. When I only have the closest aerator running alone it generates around 9 psi back pressure. When I restict it down to force an equal amount of air to the farthest aerator (valve wide open) I get about 10 psi back pressure. When I shut off the near aerator and only run the farthest one I get about 11 psi. In the summer I run them both (10 psi), in the winter I only run the far one (11 psi). I only run my aerator for two 4 hours shifts daily. Whenever the system kicks on the pressure climbs as the pump is pushing the water out of the air stones and gets high enough to trip the 15 psi pressure relief valve for a few seconds. With this arrangement my vanes have lasted almost 6 years now. I do keep another set handy for the day they crap out.
Last edited by bz; 09/02/07 11:54 PM.
