2 Separate Return Lines Or One Tee Line?

[lrodptl]

Now that I have my suction lines completed I'm tackling the return lines. There are 2 return ports. Is it better to run 2 separate return lines through a ball valve tee assembly like the suction lines or should I just tee them at the first return port?

[Pathfinder]

As far as I see it T's are counter productive for proper flow in your pool. A few years back I used my friends pool as a project when I replaced the return lines I ran 2 separate lines from the returns to meet up at a Y fitting after the heater it improved his flow dramatically. When you use a Y you will have equal flow to your returns instead of one return receiving more flow and the other starting up once there is enough back pressure form the primary. Now on all installs I use a Y for the returns & no 90's I use sweep 90's and 45's if I have to. PVC Y's are not that common. You can use an ABS Y as long as its not buried and you used Primer and transition glue.

[lrodptl]

As far as I see it T's are counter productive for proper flow in your pool. A few years back I used my friends pool as a project when I replaced the return lines I ran 2 separate lines from the returns to meet up at a Y fitting after the heater it improved his flow dramatically. When you use a Y you will have equal flow to your returns instead of one return receiving more flow and the other starting up once there is enough back pressure form the primary. Now on all installs I use a Y for the returns & no 90's I use sweep 90's and 45's if I have to. PVC Y's are not that common. You can use an ABS Y as long as its not buried and you used Primer and transition glue.

Are you talking rigid Sch 40 PVC? I'm not familiar with sweep fittings either.

[lrodptl]

As far as I see it T's are counter productive for proper flow in your pool. A few years back I used my friends pool as a project when I replaced the return lines I ran 2 separate lines from the returns to meet up at a Y fitting after the heater it improved his flow dramatically. When you use a Y you will have equal flow to your returns instead of one return receiving more flow and the other starting up once there is enough back pressure form the primary. Now on all installs I use a Y for the returns & no 90's I use sweep 90's and 45's if I have to. PVC Y's are not that common. You can use an ABS Y as long as its not buried and you used Primer and transition glue.

Are you talking rigid Sch 40 PVC? I'm not familiar with sweep fittings either.

I found them,thanks.

[Mark]

I would go with a manifold assembly at the pad and run separate lines to each return. This will reduce head loss considerably. 2 x 2" lines are equivalent to a single 2 1/2" line.

The trade off between a TEE vs Y is probably less important and if you go with a 2 1/2" manifold then it probably won't matter much at all and it is much easier to make a manifold out of TEES than Ys.

[lrodptl]

I would go with a manifold assembly at the pad and run separate lines to each return. This will reduce head loss considerably. 2 x 2" lines are equivalent to a single 2 1/2" line.

The trade off between a TEE vs Y is probably less important and if you go with a 2 1/2" manifold then it probably won't matter much at all and it is much easier to make a manifold out of TEES than Ys.

Would you include a ball valve Tee setup as I have on my suction side? Also,any opinion on those "sweep" fittings? I'm intrigued. I don't think I've ever seen ball valve Tee manifolds for both return and suction lines. Thanks.

[Mark]

Normally you don't really need ball valves on the returns since it is best to keep them open all the time for maximum flow but they are cheap and if you can think of any reason why you might want to have just one return on (I can't), then you might want to include them. There is probably not much harm in adding them although sometimes they do leak when they get old but then you would have that problem with the suction side as well.

Also, a 2" Tee branch side has the same head loss as 12 feet of straight pipe. At 100 GPM, this less than 2' of head so it won't really add that much. If that is too much then make the manifold out of 2 1/2" pipe which drops the head loss to less than 0.8 feet of head. So I would probably just go with standard fittings but upsize the manifold.

[EDIT] Forgot that only half the volume of water will be traveling the branch side of each tee so for 2" pipe, the head loss is less than 0.5 feet and for 2 1/2" it is less 0.2 feet. The manifold will have two branch tees for each line so double the numbers for total head loss in the TEEs.