Pipe size

[btmansfi]

Good afternoon. I have roughly 10 years of experience owning pools, having purchased a home that already had a pool to having one built. We just sold our home and purchased another home that has a pool. It's a large Grecian true L but needs a ton of work. Liner is shot and all equipment is trash. Also, there's only the standard 3' concrete deck.

We definitely have our hands full. I've replaced pumps, filters, and salt cells and I have an account with a local pool distributor so I am going to handle that. Going to pay someone to do the liner. I'm trying to map out chronologically how this all play out and one "issue" that I thought of is pipe size.

Pretty sure the existing pipe is 1 1/2". It's a roughly 40k gallon pool and I was planning to go with the Hayward Tristar VS 950 2.7 hp pump. We'll also have 4-6 deck jets and down the road, a spillover spa and water feature. With all of those things I would imagine the 1 1/2" pipe is going to be a limited factor in supplying the volume of water needed for all of those accessories. Being that we're going to be tearing the concrete out, we could possibly excavate enough to get to the pipe and replace it. Just not sure if the cost is worth it or not.

Is leaving the existing 1 1/2" pipe there going to make going with this pump a bad idea? Would a smaller pump be a better option for us?

 

[1poolman1]

Good afternoon. I have roughly 10 years of experience owning pools, having purchased a home that already had a pool to having one built. We just sold our home and purchased another home that has a pool. It's a large Grecian true L but needs a ton of work. Liner is shot and all equipment is trash. Also, there's only the standard 3' concrete deck.

We definitely have our hands full. I've replaced pumps, filters, and salt cells and I have an account with a local pool distributor so I am going to handle that. Going to pay someone to do the liner. I'm trying to map out chronologically how this all play out and one "issue" that I thought of is pipe size.

Pretty sure the existing pipe is 1 1/2". It's a roughly 40k gallon pool and I was planning to go with the Hayward Tristar VS 950 2.7 hp pump. We'll also have 4-6 deck jets and down the road, a spillover spa and water feature. With all of those things I would imagine the 1 1/2" pipe is going to be a limited factor in supplying the volume of water needed for all of those accessories. Being that we're going to be tearing the concrete out, we could possibly excavate enough to get to the pipe and replace it. Just not sure if the cost is worth it or not.

Is leaving the existing 1 1/2" pipe there going to make going with this pump a bad idea? Would a smaller pump be a better option for us?

Smaller pump? No, just turn down the RPM. Move the same water for less energy cost. For added water features you will want the larger pump.

There are thousands of pools with 1.5" plumbing, it was industry standard for decades. You just run the pump longer to get the results you want or need. Thirty years ago I put a .5hp pump on a 40K block pool that had a single 1.25" suction (Lily Pad skimmer) and single 1" return line. Filtered 14 or more hours a day and the pool stayed relatively clean for its age and strange location of the plumbing , return was one foot away from the suction line. Water was always good, pool itself, not so much, no auto cleaner.

If you add a spa, be sure to plumb that with 2" or larger pipe. For future water features the same. You will need to run new lines for those and want to use the larger pipe. For ease of installation, as you change things above ground, use 2" as well for as much as possible as virtually everything is designed for that. Won't have to get bushings to use smaller pipe.

 

[Newdude]

How old is the pool ? Is this the first liner change ? If the plumbing is already decades old, it may not last as long as the new decking. If that is any iota of a concern, I'd replace thr plumbing now, and once you've dug it up, then use larger plumbing just because.

 

[JamesW]

a spillover spa and water feature.

How will this be added?

How much flow is required?

How many suction lines do you have?

You want to keep the water velocity below 6 ft/sec on the suction and below 8 ft/sec on the pressure side of the pump.[7]

Pipe Size	6 ft/sec	8 ft/sec
1.5"	38 GPM	51 GPM
2"	63 GPM	84 GPM
2.5	90 GPM	119 GPM
3.0"	138 GPM	184 GPM

Equipment Pad Best Practices - Further Reading

www.troublefreepool.com

 

[btmansfi]

How old is the pool ? Is this the first liner change ? If the plumbing is already decades old, it may not last as long as the new decking. If that is any iota of a concern, I'd replace thr plumbing now, and once you've dug it up, then use larger plumbing just because.

Pool was built in 2000. The previous owners completely neglected it. The liner looks maybe 5 years old but it's ripped. It doesn't look like they used it in the last several years.

 

[Newdude]

Pool was built in 2000

So you have a tough call to make. Modern plumbing *should* last forever, but of course, nothing lasts forever.

Your new decking will last 30 years. Will the plumbing make it to 53 ?

 

[btmansfi]

So you have a tough call to make. Modern plumbing *should* last forever, but of course, nothing lasts forever.

Your new decking will last 30 years. Will the plumbing make it to 53 ?

My only concern with attempting to excavate to get to the plumbing is that the pool is dug about 2' higher than grade. Water table is really high here, so to do an 8' pool they had to dig it that way. So, there is quite a bit of slope off the pool. My fear is excavating "could" compromise the walls of the pool. Maybe I'm just being paranoid...