Using Pool Pump to Blow Out Lines?

[Poconos]

Chuck is right. I want to add something else because there have been many posts and questions about using an air compressor to blow lines. For all but a main drain it isn't a good idea. An air compressor usually supplies a low volume at a high pressure. This could be fine for a main drain where the pipe going to the drain is at a steep slope. You would tend to push all the water out the drain and no water would settle in the pipe. A main drain is a specific case where you are trying to displace possibly an 8 foot column of water and you need more pressure than a shop-vac can develop. If you have long horizontal runs like to the returns, you want a high volume of high velocity air to try and move as much water out the pipes before you plug the returns. If you use a low volume and low veloity you could leave some water that could settle at low spots and possiby freeze and break a pipe. Depends on how it freezes. Think about the analogy of using a leaf blower to clear puddles off a flat slab of something. When I blow my returns I let the things bubble vigorously for probably 10 minutes before plugging. Back to the original question about the pump. Both shop-vacs and pool pumps are centrifugal pumps. One is designed for liquid and the other for air. Motor speed on a pool pump is usually 3450 RPM (single speed) while a shop vac is many thousands of RPM, probably over 10,000. Never measured one. Same with a vacuum cleaner motor/pump. The much higher motor speed is necessary because of the lower density of air versus water. Hope this sheds a little more light on the situation of blowing lines.
Al

[NullQwerty]

Makes sense guys....Thanks for clearing that up!