To test & or replace return lines.....

SplashDIY

Active member
May 26, 2024
31
Coastal North Carolina, USA
Hello everyone,

I have been working on this pool system for over a week. Each time I halt flow, I have a devil of a time re-establishing same, even when just focused on the skimmer line. You can see the various hacks I have implemented, aiming to inject water from a garden hose. It's still a battle. I was racing to keep ahead of the pool turning green.... now it's time to figure out if I have vacc leaks in either/both returns.

I'm now beginning to expose the pipe run (all this installed before we bought this home, no history avail) - I can already see how poorly the return lines were laid in. Look at the proximity to the overhead (and 200lbs+) propane tank! The lines, moving away from the equipment pad and back to the pool, snake slightly upward from the initial 90 transition (from vertical to horizontal). Never more than a few inches below grade, they then dip again, go to 45 elbows, and then seriously start descending. It's aprox another 50 ft until they will cross under the pool deck.

My thought is to excavate and expose these until I reach an insurmountable submerged obstacle, or the deck edge itself. What I could then do is run new, straight pipe runs to the equipment pad - the line includes sand and a section of garden with pebbles to remove. I am wondering it would be important to lay in that new section as close to horizontal as possible? Does that have a significant positive effect on fluid flow?

After this is done, I could run a pressure test on at least the skimmer line. As for the main drains return line, I cannot think of any way to test that. Potentially, both skimmer and drain lines could have vacc leaks..... Even when I have good flow established with the skimmer line, if I open the cut-off valve for the main drains, even slightly, I immediately lose flow again. It's tough to get any water flow, even with all the flow injection points I have added (see my fitting for the skimmer box - cobbled together from scrap Sched 40 pieces from someone else's debris pile).

Any other ideas as to how to proceed? Would it be better to pressure test the existing lines before taking anything apart? I know for sure I want to at least replace the section of run under the propane tank!
 

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Hello everyone,

I have been working on this pool system for over a week. Each time I halt flow, I have a devil of a time re-establishing same, even when just focused on the skimmer line. You can see the various hacks I have implemented, aiming to inject water from a garden hose. It's still a battle. I was racing to keep ahead of the pool turning green.... now it's time to figure out if I have vacc leaks in either/both returns.

I'm now beginning to expose the pipe run (all this installed before we bought this home, no history avail) - I can already see how poorly the return lines were laid in. Look at the proximity to the overhead (and 200lbs+) propane tank! The lines, moving away from the equipment pad and back to the pool, snake slightly upward from the initial 90 transition (from vertical to horizontal). Never more than a few inches below grade, they then dip again, go to 45 elbows, and then seriously start descending. It's aprox another 50 ft until they will cross under the pool deck.

My thought is to excavate and expose these until I reach an insurmountable submerged obstacle, or the deck edge itself. What I could then do is run new, straight pipe runs to the equipment pad - the line includes sand and a section of garden with pebbles to remove. I am wondering it would be important to lay in that new section as close to horizontal as possible? Does that have a significant positive effect on fluid flow?

After this is done, I could run a pressure test on at least the skimmer line. As for the main drains return line, I cannot think of any way to test that. Potentially, both skimmer and drain lines could have vacc leaks..... Even when I have good flow established with the skimmer line, if I open the cut-off valve for the main drains, even slightly, I immediately lose flow again. It's tough to get any water flow, even with all the flow injection points I have added (see my fitting for the skimmer box - cobbled together from scrap Sched 40 pieces from someone else's debris pile).

Any other ideas as to how to proceed? Would it be better to pressure test the existing lines before taking anything apart? I know for sure I want to at least replace the section of run under the propane tank!
If you just want to pressure test. You can plug the returns and then remove the filter output union and pressurize it from there.
 
'Progress report' from this hydraulic overhaul project - I have excavated to the pool deck, traversing under a privacy fence. The original pipework is a mess. The lines snake around each other - it's an effort to trace each one from the pad to the end of the trench!

My plan for today is to cut thru and cap right by the pool deck. Cut again at the equipment pad, and I can lift all runs out to the surface. I will then establish a level from the point where the pipes feed under the pool deck (this is set at 5" below the pool water level when full) and retrench to this grade back to equipment pad. (that's going to be a lot of digging on the high side).

Ideally I would avoid making the 45 degree turn (known to be problematic during this type of assembly), but I don't see the 'juice is worth the squeeze' in establishing a new trench, which would allow for 90's. Part of my trench line goes under pebbles and weed barrier, so that will all have to be repaired within the near future.

Because the lay-in of this pipe is so obviously wrong, I am not going to spend any time rigging pressure tests. My hope is that with this 50+ foot of pipe now laid in BELOW the fill water line, the poor old pump is going to have an easy time catching prime. I will however flow-function test it for a few hours before closing in!

PoolStored - you are right on the money. With the pump running for several hours, there is a persistent air stream coming out of one or more returns. I still suspect - and correct me if I am wrong (?) - that this would probably be caused by this incorrect pipe work, referring specifically to its crazy grade. In terms of efficiency of work flow, I am intending to correct the trenches and installation, run a test.... I am anticipating that the entrained air will quickly disappear. Fingers crossed, metaphorically speaking!

A question - is anyone aware of a set of 'best practices' for laying this pipe back in? So far, I am just going with my commonsense/intuition, based on my elemental knowledge of hydraulics - lay it all back in BELOW the waterline, only coming above grade when right by equipment pad. Seems like a good idea to keep the lines laid out side-by-side, instead of snaking above-below-around each other.

I do find myself wondering if some plumbing upgrades would make a worthy difference - eg : 90 degree sweeps (I have 5 on hand, would need to search for just a few more), and hey, what if this was all redone in 2" Sched 40? To give perspective - this would represent aprox 50-60% of the entire plumbing system. If there was a time to do it... this is it. Thoughts?

Thanks again everyone!
 

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Pool plumbing lines replacement & upgrade - latest progress report....

This has been a big effort - and I could not have predicted how many days it would take to do all this alone. Some of this work is VERY inefficient and time consuming without a helper - too much time trying to rig a one person solution.

I eventually found a supplier with 20 ft Sched 40 in 2", but it required leaving town. Because I cut these trenches as narrow as possible (less than 6" width), laying in 20 ft sections - 90 deg sweeps on one end to transition to vertical/pool pump-and-filter pad, with a slip butt join in a narrow trench on the other, I had a very tough time doing this alone. I am digging in what is almost beach sand (½ mile inland from the dunes). NOW that I have a full measure of this project, I would get as much of this done with a mini-excavator as possible. I think 10 ft sections would have been a better choice - I was of course seeking as always to minimize the number of solvent-welded joints.

Low voltage conduit (2 x ¾") are the last to lay back in; no need to take account of its position with regard to the filled water level in the pool itself. But something is worrying me - as I laid back in aprox ½ of the conduit, an unbroken run from under the pool deck, water was running out of both conduits. At first I thought 'Oh good, we're losing some entrained water' - the original installers had the 12 volt cables coming out of conduit above grade, with the open conduit ends pointing to the sky, naked cables then meandering off towards the weather proof box). I came back an hour later, the pace of water draining out had not slowed - and so now I knew that this must be water from the pool itself.

I have no experience with lighting installations done below the water line. What kind of failure might I be dealing with here?
I am, for now, simply going to complete the ¾" conduit run back to the the transformer box, and close it in. The water will of course find its own level inside these conduits. (I halted the water flow overnight by simply propping the ends up above grade).

To worry about - later - will this mean draining the pool down to access the lights? Will servicing be possible from the front side (fingers crossed) OR could it involve breaching the concrete decking and going in from that side? Well, never mind - for now, I need all my energy to close these trenches in. We have people arriving early this coming week, and TheDarlingWife told them to enjoy the pool.

Last minute thought before sending this - my trench was up to 40" deep in order to keep it below the water line of the pool. I may as well fill most the trench in and then lay in electrical at a more shallow depth, keeping as much as possible above the water line. Less cable setting in chlorinated and salted water... to come back to this later.

I feel tired....
 

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Pool plumbing lines replacement & upgrade - latest progress report....

This has been a big effort - and I could not have predicted how many days it would take to do all this alone. Some of this work is VERY inefficient and time consuming without a helper - too much time trying to rig a one person solution.

I eventually found a supplier with 20 ft Sched 40 in 2", but it required leaving town. Because I cut these trenches as narrow as possible (less than 6" width), laying in 20 ft sections - 90 deg sweeps on one end to transition to vertical/pool pump-and-filter pad, with a slip butt join in a narrow trench on the other, I had a very tough time doing this alone. I am digging in what is almost beach sand (½ mile inland from the dunes). NOW that I have a full measure of this project, I would get as much of this done with a mini-excavator as possible. I think 10 ft sections would have been a better choice - I was of course seeking as always to minimize the number of solvent-welded joints.

Low voltage conduit (2 x ¾") are the last to lay back in; no need to take account of its position with regard to the filled water level in the pool itself. But something is worrying me - as I laid back in aprox ½ of the conduit, an unbroken run from under the pool deck, water was running out of both conduits. At first I thought 'Oh good, we're losing some entrained water' - the original installers had the 12 volt cables coming out of conduit above grade, with the open conduit ends pointing to the sky, naked cables then meandering off towards the weather proof box). I came back an hour later, the pace of water draining out had not slowed - and so now I knew that this must be water from the pool itself.

I have no experience with lighting installations done below the water line. What kind of failure might I be dealing with here?
I am, for now, simply going to complete the ¾" conduit run back to the the transformer box, and close it in. The water will of course find its own level inside these conduits. (I halted the water flow overnight by simply propping the ends up above grade).

To worry about - later - will this mean draining the pool down to access the lights? Will servicing be possible from the front side (fingers crossed) OR could it involve breaching the concrete decking and going in from that side? Well, never mind - for now, I need all my energy to close these trenches in. We have people arriving early this coming week, and TheDarlingWife told them to enjoy the pool.

Last minute thought before sending this - my trench was up to 40" deep in order to keep it below the water line of the pool. I may as well fill most the trench in and then lay in electrical at a more shallow depth, keeping as much as possible above the water line. Less cable setting in chlorinated and salted water... to come back to this later.

I feel tired....
The conduit on older light fixtures was not sealed and the water level was allowed to find its own level in the conduit as long as the conduit daylighted above the water line nearby the fixture. Then a separate run goes back to the transformer. I wouldn’t run a single line back to the transformer. You want as little water filled conduit as possible. IMO, the conduit should be sealed off at the fixture.
 
Thanks gents. PoolStored - yes, this is all Sched 40. (both 2" and ¾" runs).
Bperry - I would not have guessed this! Since I cannot access any of the remainder of the conduit runs once they go under the concrete pool deck, what I can do is run the conduit 'high' right by the edge of the deck. That will be as far as water can migrate back from the pool light fixtures. Beyond that point, the rest of the conduit can return below grade as makes it way back to the equipment pad. Great information - thanks much.
 
Thanks gents. PoolStored - yes, this is all Sched 40. (both 2" and ¾" runs).
Bperry - I would not have guessed this! Since I cannot access any of the remainder of the conduit runs once they go under the concrete pool deck, what I can do is run the conduit 'high' right by the edge of the deck. That will be as far as water can migrate back from the pool light fixtures. Beyond that point, the rest of the conduit can return below grade as makes it way back to the equipment pad. Great information - thanks much.
You generally want there to be an accessible junction box near the fixture to make replacing the lighting cable/fixure possible in the future. You dont want any electrical splices buried.
 
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