PVC size advice - NEW pump install (pics)

Aug 6, 2022
13
Arizona
Tomorrow I am installing a new 2HP variable speed pump to replace my old 1HP single speed. I'll explain the set up, but for now, juat note that both suction and return lines are 1.5" PVC.

I'll add pictures because there is a LOT of reducing and 1.5"-2" and vice versa...

SUCTION:
- 1.5" Cleaner line into 2" Jandy
- 1.5" Skimmer line into same 2"Jandy
- That 2" Jandy feeds into the pump at 1.5" reducer

20220804_111548.jpg

PUMP TO FILTER:
- 2" leaving pump reduced to 1.5"
- 1.5" fed into 2" elbow that connects to 2" push pull
- 2" push pull reduces to 1.5" into 72 GPM DE filter

20220810_182047.jpg
20220804_111603.jpg
20220810_182019.jpg

FILTER TO RETURN:
- 1.5" from filter to 2" push pull
- 2" push pull reduced to 1.5" return PVC
- 1.5" return PVC to 3/4" T connector for airator valve
- Other 1.5" side of the T feeds into a 2nd Jandy at 2" connection
- Jandy splits into two 1.5" returns (one for return jets, one for water feature)

20220810_182114.jpg

Okay, so that's messy to read and even messier to look at. My question is about flow and pressure if I bypassed all the reducers and 1.5" to 2" craziness. KEEP IN MIND, both suction and return are 1.5".

Can I go from the two 1.5" suction to 2" into the Jandy & pump...2" into the 72 GPM filter...2" back into the return Jandy which feeds the two 1.5" return lines?

All safely and efficiently, of course :)

Will the new 2HP pump provide too much flow through 2" PVC for a 72 GPM filter and can this damage the returns going from 2" back to 1.5"?

I know I'll need to play with the RPM's but in theory, is this the 2" above ground PVC conversion a good or bad idea?

Thank you!

Thanks!
 
Last edited:
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Stay with 2” PVC on the equipment as much as you can.

Your filter will be fine with the flow from your new pump.
 
So the cost of 2 new Jandy's and a new push/pull valve outweigh sticking with the existing plumbing?

I didn't say that.

You will see no operational difference in all 2" versus mixed 2" and 1.5".

Going to run around $350 to upgrade just the valves/PVC.

I would keep it 2" pipes and fittings. Replace the valves with 2" when they need replacement.

BTW, I would put in an MPV when you replace the push/pull valve.
 
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I didn't say that.

You will see no operational difference in all 2" versus mixed 2" and 1.5".



I would keep it 2" pipes and fittings. Replace the valves with 2" when they need replacement.

BTW, I would put in an MPV when you replace the push/pull valve.
Push/pull is leaking so thats a must. MPV does sound like a better option.

I'll leave the existing Jandy's and use 2" where I can. Thanks!
 
Make sure you get the correct MPV that matches your filter model.
 
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Push/pull is leaking so thats a must. MPV does sound like a better option.

I'll leave the existing Jandy's and use 2" where I can. Thanks!
While an MPV does have a minor increase in flow, a D.E. filter only requires two positions, filter and backwash. Unless you want all the options (that you have never needed so far), a new push/pull will be easier to install and less expensive.
 
While an MPV does have a minor increase in flow, a D.E. filter only requires two positions, filter and backwash. Unless you want all the options (that you have never needed so far), a new push/pull will be easier to install and less expensive.
I took this advice. Looking at my setup and all the additional 90 elbows involved, I decided to stick with the push/pull. Saved about $100 this way too.

Since my old 1HP ran at 3450 RPM all the time, is it safe to say that a 2HP running at 3450 will be the same GMP?

Increasing form 1.5" to 2" PVC, I would imagine more flow into the filter, correct?

Without adding a gage, I want to be sure I stay under the advertised GPM of 72 on the filter.

Thanks.
 
I took this advice. Looking at my setup and all the additional 90 elbows involved, I decided to stick with the push/pull. Saved about $100 this way too.

Since my old 1HP ran at 3450 RPM all the time, is it safe to say that a 2HP running at 3450 will be the same GMP?

Increasing form 1.5" to 2" PVC, I would imagine more flow into the filter, correct?

Without adding a gage, I want to be sure I stay under the advertised GPM of 72 on the filter.

Thanks.
The purpose of a VSP is to run as slow and long as possible to keep the pool clean, chems mixed. A 2hp will very much move more water at the same rpm (but not double). That is too big a pump to run at full speed and you don't want to.
 
Think its all a bit futile uprising piping from 1.5 to 2" for the pump and filter if the pools plumbing is 1.5". It won't flow faster through the pump and filter because of the rest of the resistance called "head". Plus any 1.5" connection in the system creates a bottle neck restricting flow.
At 32ft head, a combined total of pipe diameter, all pipes, and the distance there and back from the furthermost jet, plus elbows, MPV, non return valves and so on. 32Ft is not hard to reach, its not all just vertical height as the name head suggests.
A 1Hp pump pushes 76 gpm generally.
1.25HP 87gpm
1.5Hp 103gpm
2HP 126gpm.

Going on you filter volume size perhaps a 1HP variable speed is required. Of course if you head is more than 32ft than maybe a 1.25HP could be considered.

just my 10c worth
 

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