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challenging pvc problem

Posted by scrappy57 (My Page) on
Tue, Feb 5, 13 at 9:33

I'm going to build a 1000 gallon spa outside my slab-on-grade house. My original intent was to heat the spa with the 130,000 Btu/hr output high efficiency hot water heater augmented with solar panels on the roof. The "boiler room" is in the back corner of the house and my heating contractor/spa specialist POSER who didn't have a clue what he was doing placed a 4" pvc chase under the slab to the spa location 80' away with only a pair of Rehau Pex (only 13/16" inside diameter) to heat the spa. The slab is poured, the house is built. The spa is the last step before I'm finished. Once I excavate for the spa I'll yank the undersized Pex pair out and replace it with schedule 40.

But the largest suction/returns schedule 40 pipe I can fit inside the 4" chase is two 1/5" diameter pipes ' and they only fit if I use "repair couplings" aka "flush inside slip couplings" (they're the same outside diameter as the 1/5" schedule 40 pipes and made so they have 2 street ends or spigot ends [2 ways to say the same thing]. They reduce the ID of the pipe at the connection, so I'll lose some flow there, but as I'll only need 3 pairs of them to get to the boiler room and back, it shouldn't be too bad.
My big problem is this: I can't find any made as elbows. They're all straight. I've tried plastic oddities, spears, nibco, and midland and nobody knows where I might find 45 degree elbows made that way. It'll take 2 pairs of 1.5" 45 degree elbows to get thru the pair of 4" 45's that I created the sweeping elbow with that gets me from under the slab to above it in the boiler room.

The only solutions I've come up with are heat bending some sections to try creating the shape I need, then reaching them into the 4" pvc from above the slab and gluing them to some repair fittings that I'll have prepped on the ends of the 1.5" pipes that I've stuck thru from 65' away outside. It's either that, or I have to take out a section of 4.5" slab, cut off the 4" sweeping turn, poke the pair of 1/5" pipes thru, use conventional fittings to get back above the slab, then sleeve and bush them to protect them from being solidly poured in the slab. Does anybody have a better idea?


Follow-Up Postings:

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RE: challenging pvc problem

photo of my pvc chase coming thru the slab


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RE: challenging pvc problem

If I understand this correctly why could you just not use Tiger Flex as see below?

Here is a link that might be useful: Tiger flex


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RE: challenging pvc problem

Thanks Muddy, but flex pvc has a bad reputation in the pool and spa world. It's already soft, and when you heat it, it gets softer. Plus, it has a high shrink/swell rate and tends to wear itself out in heat/cool cycles wherever it touches anything. I'm hoping for a real long term fix.
My plan at present is to take sections of schedule 40 and put them upright in small margarine containers full of water and freeze the ends in little blocks of ice - then attempt to heat bend the shape I need while the iced ends remain un-deformed by heat. That's the best plan I've come up with so far.


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RE: challenging pvc problem

The existing lines will need to be abandoned. I know it implies a lot but there is no way around it. Yes, the PB/sub was an idiot.

PEX is not made for pool use. It will degrade and leak with long term exposure to chlorinated water.

PEX is great for radiant heating in the floors of a house.

Scott


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RE: challenging pvc problem

I'm not a big fan of tiger flex in dirt but in a race with no joints I might make a exception....The biggest problem I have seen is Termites....And for portable spas I have really never seen any problems unless they used baquacil.Other than that how about a pipe extender?

Here is a link that might be useful: Pipe Extender


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RE: challenging pvc problem

Righto Scott, the guy was an idiot. And yea, Muddy, I'm tempted to use flex at least at the end where the bend happens - I've just read so much on the forums from experts who hate it and say it's only trouble. I could attach it with flush inside couplings to the ends of my rigid pipes before pushing them thru the chase from outside. Then I could pull and push them thru the bend in the 4" chase. But the connection would be below the slab and, if it ever failed, I'd still have to go thru the slab to fix it. I'm a mason by trade and out of my area of expertise here, but if it failed while the spa was in use I'd have a big mess. If I can just get it right from the start I can rest easy. And as a mason, I'm not too intimidated about going thru the slab to make it right now - but it's a big messy job and I'd rather not, if I can find a way around it.


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RE: challenging pvc problem

I was just thinking by using the Flex you would not have 90s so less reduction in flow should be the result... Did you look at the pipe extenders for your hard pipe needs?


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RE: challenging pvc problem

My plan to heat bend schedule 40 would create curves as smooth as the flex, it'd just be difficult to do. Pipe extenders don't mean anything to me here, since I'll be stuffing 20' sections of 1.5" pvc thru the chase from 65' away outside. If I need more horizontal reach, I'll just push more in. It's just curving back up thru the slab that's the problem.
I was hoping one of you "real" pool types would have an alternative to the things I've already considered. But I guess I did my homework, cuz nothing's coming up that I haven't already considered. I do appreciate the feedback tho.


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RE: challenging pvc problem

Please, I know it sounds like a lot, but abandon the existing stuff entirely. Its the wrong pipe for the water. The race way wouldn't be needed with hard pipe. Don't cement right up to pipe. Look at it as square foot gardening with gravel surrounding the pipe where it surfaces.

Scott


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RE: challenging pvc problem

Poolguy, thanks for your responses. Respectfully,if you read my original post more thoroughly, you'll see that all of your input is missing the point.
I've already stated the chase is Under the slab (maybe I should have been more clear, it can't be abandoned, it's the only way out of the building now cuz the boiler room is in part of the house that's below 10'grade) and I'm pulling the Pex out and replacing with PVC. My question is to see if anyone has a better strategy than I already have for making the turns to get thru the slab.


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RE: challenging pvc problem

As I said, it ain't easy but it is the right way to do this.

Send the lines that were to go down the raceway in the basement to the wall and climb/clamp before going outside. Then you need to cut a path to the spa lines.

Ugly? Yeah. How it should have been done the 1st time? Yup. I think so.

This isn't a regular portable spa application, there is too much distance. Flex, whether Tiger pipe or PVC Flex, will wear. Hard pipe won't. The PEX is attached somewhere near the spa. I imagine, so the cut, remove, and dig are inevitable.

Scott


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RE: challenging pvc problem

Thanks, Scott, but I can't do that. There's already concrete poured outside and to go out and around the house would add 100' to the already 80 feet to the spa. My Only way out is thru the chase. And because the Buffoon who had me put insufficient sized chase in, I will only be able to take care of spa maintenance temps from the boiler room using the water heater and future solar panel assist. Time-of-use heat up will be done with an electric heater from the basement of the nearby gazebo.
Boy did I ever get stuck. This guy was listed by NC State University Solar Center as a worthy radiant heating/ solar heating and spa contractor. I made the mistake of believing them. You wouldn't believe the nightmare. He installed more than 100 code violations, the heater doesn't keep up when it's truly cold out, he double billed me, then sued me when I wouldn't give in to his demands to actually DO the job he'd contracted for (turns out I was his 67th lawsuit) and by the time my counter suit got him off my back he was on his 102nd lawsuit. He was using the court system to take money from people cuz most would give him the extortion rather than resist in court cuz it was cheaper in the long run and easier. I guess I'm too stupid or have to strong a moral compass to give in. I fought for 4 yrs and spent Way more on legal fees than his extortion price, but I fought back. I put the licensing board onto him and he's gone now, but I'm stuck with what I've got. The only way from the boiler room to the spa is thru my 4" pvc raceway.


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RE: challenging pvc problem

The fact that the outside is poured is a bummer. I can appreciate that a cut in the slab and digging a trench to 2' depth is no fun out there ,makes for a royal PITA but it really needs to be done, but trying to use the raceway is, IMHO, a mistake. The raceway would require you use flex and that, on a spa, is not a good idea. The heat, the expansion and contraction will cause it to fail.

Bumping up the plumbing at least to a 3" suction and 2-1/2" on the return will help ease any head loss from the distance. If you have an air line too, make that 2" pipe and use at least a 1.5 HP blower but put it outside and above the waterline.

Speaking of heat, be able to divert flow to the heater. I doubt it can or should take the full flow. Forget about the solar. It is way too slow for this application. The height to the roof from the basement is likely to be too much too.

Scott


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