Stick with 2 inch PVC or convert to 3 inch for a plumbing extension - reconfiguration

Jun 8, 2018
5
Landenberg, PA
Hi
I am re-plumbing my equipment for a large 20 year old Gunite pool to accomplish a few related goals.
1. Replace old Propane Heater with Heat Pump (Propane is very expensive to use and not exactly environmentally friendly to heat a pool).
2. Move equipment around so that I can use the space that equipment is currently at for a small pool house/equipment shed/control center.

I am planning to place my DE Filter, Pump, Valve and Salt Cell in the back corner of this new structure that drill through the walls and dig a trench to the heat pump 8' away where there is more space for it.

In the end I will end up with longer plumbing runs to get to and from the heater and to get to the main return line from the pool. I tried attaching photos but even after resizing they are too big. I will get them on there as some point.

Generally I like to try and use supplies I can get locally so that if I am short one fitting or something goes wrong and I need a fitting I can just get one without waiting for shipping. Home Depot and all others locally do not have pressure rated fittings greater than 2'' PVC and no 2.5'' PVC 10 foot segments. If I want to go bigger to reduce the total system pressure head, it seems like I need to get 3 inch Schedule 40 pipe locally and then order all the fittings such as these. https://www.supplyhouse.com/Spears-406-030-3-PVC-Sch-40-90-Elbow.
My question is this worth it? The new heat pump heater has 1.5'' inlet and outlet, my salt cell has 2'' threaded connections. So I will end up reducing the 3'' down to 1.5 to go into and out of the heater and then I have to reduce to 2'' for my salt cell and check valve (to avoid backflow of highly chlorinated water into the heater when the pump is shut off). I will of course have a bypass for the heater so that when I am opening, closing and cleaning I can run the pump at full speed without the heater in the loop.

I need to decide quickly as I want to get this operational and it is a whole lot easier to just use 2'' Schedule 40 PVC throughout but I do not want to take the easy route and regret it later. I plan to live here a long time, and we use the pool as much as I can in our medium length season in southeastern Pennsylvania.

 
Pool equipment current design. More compact that then new layout with the heater moved a back just on the other side of that aluminum fence but I lot of elbows (which is more or less normal for a pool setup).
Is there 90's that I can buy such as street elbows or sweep elbows for my new design that might reduce pressure head without having to resort to 3''?
Nate
 

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What is the pipe run distance from your new equipment pad to the pool?

Under 100', a 2" pipe will be fine. Over 100', go to 2.5" pipe. A 3" pipe should be unnecessary.

2" pipe at the equipment pad will be fine. Use sweep elbows if you want to bother. You will not see a difference between 90's and sweeps running a modern VS pump at low speeds. All the concern about system head was for when single-speed high flow was the only way to run a pool.

 
What is the pipe run distance from your new equipment pad to the pool?

Under 100', a 2" pipe will be fine. Over 100', go to 2.5" pipe. A 3" pipe should be unnecessary.

2" pipe at the equipment pad will be fine. Use sweep elbows if you want to bother. You will not see a difference between 90's and sweeps running a modern VS pump at low speeds. All the concern about system head was for when single-speed high flow was the only way to run a pool.

The main runs to the pool are the same 2 inch (I connect up to the original locations, but I am extending the runs by about 25 foot total.
I can use 3 inch to and from the new heater for two just under 10 foot segments each or I can just use all 2 inch.

I am using a Hayward 1.85THP VS pump and typically run it at the lowest speed acceptable to the salt generator. I run the pump 24/7 because I live in a forest and there is a need to constantly skim. I cut back the trees over the pool but there is always debris for far away trees.