Welding a lot of PVC joints...

[leejp]

I am going to plumb in my new filter+pump tomorrow. I've got pretty much all of it dry fitted so all that's left is the welding.

I've done simple drain lines for home plumbing only and have never actually welded this many PVC joints before (estimate ~50).

With many valves, unions, elbows... in tight quarters, I'm wondering what the best plan of attack is...


Weld away from the pump+filter or weld in place?
how long to wait for each joint to set before welding on another piece (this could take some time if I have to wait 15 minutes between each weld).
best approach to get the unions + valves to line up (straight line marked with a sharpie?)Any advice?

[cruzmisl]

Stop doing the same projects as me:D This is strange, I too am replumbing my entire system tomorrow. I also dry fitted all my stuff but the valves coming out of the ground aren't square to the pad so I might have to resort to using some flex pipe (:( ) I hate that stuff. It looks like crap after a year.

The only question I can answer is #2 - the time before moving to the next joint is 3 seconds.

What I fear most is getting all this done and having a leak :eek: :eek:

[matt4x4]

I would do all my work in place, not away from the situation, you are going to get much more accurate joints that way.

Even in tight places, it's relatively easy to assemble PVC properly.
Good luck to both, hope it all comes out dripless.

[catnip]

leejp,

I just finished replumbing my system and will pass on the lessons learned:

1) If you have some parts that you know the exact dimensions and geometry of the setup, you can do that in your workshop. I did that with a couple of diverter valves, a check valve and associated elbows. Otherwise, as Matt4x4 advises, do the rest on site.

2) Make sure your pump and filter are level with each other and the ground. This ensures you piping will square up without putting any stain on the pump and filter fittings. I had to shim up a filter that was nearly 10 degrees out of level.

3) Technically, 1.5 - 2.0" PVC requires 30 minutes after gluing before movement, but practically you can proceed after 1-2 minutes if you handle the joints gently. Be SURE to HOLD the joints together for 30 seconds after insertion as they will tend to back out. This can take quite a bit of force on 2" fittings, so be sure you are in a good potion to exert the required force. Here are some good links on gluing techniques:
http://www.ppfahome.org/faq-cement.html
http://www.aquaticeco.com/index.cfm/fuseaction/popup.techTalkDetail/ttid/15
http://www.elchem.com/making_solvent_cem_joints.htm

4) If you have any long runs with heavy components (valves, unions, SWCG's) be sure to provide some support along the way.

5) For alignment I used a framing square, plumb bob, tape measure and sharpie to map out, mark and check the route during assembly.

6) Use unions wherever you will need to remove something for maintenance or replacement. They are cheap at Lowe's and worth every penny.

7) Lastly, measure and remeasure before cutting, including accurate measures of the insertion depths of the pipe/fittings.

[ezpool]

I'm getting ready to do some major re-plumbing as well - I'll be adding a new heat pump in the near future and a SWG later. Plus, I need to remove some leaking, rusty gate valves from the original install. What do folks recommend for fittings/connections - should I be using PVC slip unions everywhere or are those usually reserved for big things (filters, heaters, pumps) while Jandy valves are just glued in place? Thanks!

[Poconos]

Another hint...when you do the dry fitting you probably won't get all the joints to seat all the way. Sched-40 fittings seat 1.25". Then when you goop they seat all the way and measurements are off.
Al

[JohnT]

Another hint...when you do the dry fitting you probably won't get all the joints to seat all the way. Sched-40 fittings seat 1.25". Then when you goop they seat all the way and measurements are off.
Al

I'll quote that just to emphasize how important it is.

It's also handy to write notes and little arrows in pencil on the pipe about which end goes where and what direction it goes so you don't point an elbow the wrong direction.

I've also found that dry fitting can mislead you into skipping a joint when it comes time to glue. Not a good feeling when you see that an unmoveable joint in the middle is leaking because you forgot to glue it. Purple primer is your friend for anything underground, but it looks pretty bad above ground unless you'll be painting the pipe.

Make sure you have some extra fittings on hand. Nothing more frustrating than messing up a section and then being short a fitting to finish.

[catnip]

I used unions on the pump, filter and SWCG. The Jandy, Pentair, Compool valves can be repaired in place, so I think unions are overkill there. You might also consider a union for any place where you can't physically make a good glued slip joint, e.g. tight spot where you have no room or flex in the pipe to fit the slip joint together.

[leejp]

It was hot today... the cement set up fast and I had to work quickly. I eyeballed non-critical measurements cut the critical ones a bit long and "honed in" on the final length (make several small cuts). Used a mitre saw... went quick. I fitted the joints using a level, tape measure and a small framing square. Everythint at least looks pretty good. Complicating this was the small concrete pad. I wanted to get the pump, filter and the chlorinator all sitting on the pad. Took some headscratching but did it. Thankfully it was a lot less than the 50 joints I estimated.

The joints look pretty good and for the most part I had a nice "bead" of goop all the way around each joint. You guys are right... the fittings do not go all the way in sometimes. I'm not really worried about leaks on the weldend joints... If I do get any. I'll use marine epoxy to seal those up.. takes 15 minutes. simple and permanent. I'm mostly worried about the unions, valves... (the threaded connections). Hope my measurements were good ant they are all square!.

Update... Here are the pics...

I had been considering keeping with my old EC-65 and 3/4 HP maxflo pump for a couple years until upgrading but when I spotted a Hayward Pro Grid 4800 + Vari-Flo Valve + 1HP Superpump on Craigslist for just $300 I just had to jump on it.

Here it is all plumbed in with ~$100 in schedule 40 or 80 fittings, valves, unions... from Home Cheapo. I also threw in a $35 in-line chlorinator from fleabay. The picture is taken after an afternoon rainstorm so the set up is wet. No leaks on the welded joints... Buttt...

A small leak (slow drip) at 1 union. I bought threaded Unions + 2 male fittings (vs a glue union) so I can re-use them when I reconfigure. Well... the union's fine but the one of the male threaded ends are leaking.
2 small leaks at the pump inlet and outlet. The leak at the inlet is forcing amall amounts of air into the loop. The outlet leak is dripping slowly.

So as I feared... threaded joints are the problem. Need to re-tighten with a liberal amount of fresh teflon tape.

Also... the fleabay chlorinater is no good out of the box (leak at the setting dial). The seller is gracious enough to send me a new one but I'm wondering if I should have spend the 2x for a Hayward or Rainbow. I had a Hayward off-line that was nothing but trouble so I thought I might as well try a no name.

The plumbing is quite intricate as it had to meet several requirements...
Everything on the pad (pump, filter and chlorinator)
plumb into existing flex-pvc skimmer, main drain and return connections
allow the connection of a no-booster-pump pressure side cleaner with adjustable flow between the returns and the cleaner port
allow room for a SWG (next years project).
easy dis-assembly for maintenance, repair and storagehttp://www.poolforum.com/pf2/%3Ca%20href=%22http://picasaweb.google.com/leejackp/20070527PoolPumpAndFilterInstall/photo#5069446585738568290%22%3E%3Cimg%20src=%22htt p://lh5.google.com/image/leejackp/RlpKz4bDomI/AAAAAAAAABo/85KapZ1tf3g/s800/P1000538.JPG%22%20/%3E%3C/a%3E (http://www.poolforum.com/pf2/%3Ca%20href=)
http://lh5.google.com/image/leejackp/RlpK04bDonI/AAAAAAAAABw/fQWn85Idbwo/s800/P1000539.JPG

http://lh4.google.com/image/leejackp/RlpK3obDoqI/AAAAAAAAACI/i_-hIEczuPw/s800/P1000542.JPG