Help! I used DWV fittings--not pressure rated


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I am trying to decide whether I need to dig up my pipe and replace the fittings. The pipe is rigid PVC, 2 inch from the skimmer to external pump and 3 inch from the bottom drain to external pump (This is to be a water garden not for fish). The pipe is rated for pressure applications so no problem there. But the fittings are marked DWV (Drain, Waste, Ventilation). The plumbing is located under the pond and is installed and covered but I haven't put in the liner. I would like to avoid if possible digging up and re-doing the plumbing.

I now realize that pressure rated PVC pipe fittings (90 degree sweeps, 45 degree connectors) would be preferable to DWV because they are rated for pressure. These DWV fittings are only on the suction side of the pump where the pressure is lower to begin with and for only 6 to 8 feet of dynamic head which the pump company engineer estimated to be only 11 pounds of pressure per square inch (PSI) maximum. DWV fittings are tested at 5 psi by convention after they are installed but the manufacturer, Nibsco, does not test or rate them so has no data. These are solid PVC Schedule 40 which is the identical wall thickness of pressure rated schedule 40, but possibly not made to be as strong as Schedule 40 PVC that is pressure rated. The DWV is approved for burial below ground.

I will water test later (after the unseasonable 23 degree F freeze tonight has passed) but am worried about the longer-term effects.

Please, does anyone have experience or knowledge of having installed fittings marked "DWV" (Drain, Waste, Ventilation) in their pond?

Any comments are much appreciated.

Pond 15' x 8' x 24 to 43 inches deep. External W. Lim Wave II pump 7000 gph with 2,000 gph (also the pond volume) going to Skippy filter (1,000 gallons) and 5000 gph from skimmer directly to waterfall.

Thanks!
Carmen
 
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sissy

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Most of those fittings are used for house plumbing in some form or the other .So if they are glued they should last .Are you in a cold climate as the depth will matter also .
 

addy1

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I would think you will be ok. It is on the suction side, like you stated, you don't have a closed system where you are going to build up pressure like house plumbing, the water will be passing through the pipes.

I used the black drain piping when I built my Arizona pond, 14k gallons, buried pipes, large pipes, never had a issue with the pipes. They where on the exit side of the pump, heading up a slight hill to a 4 foot waterfall.
 

DrCase

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I use sch 40 dwv on all my pond pipes . You want the longer turns they offer .
If I were running a water line I would use PW fittings
 
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Sissy, Addy1 and DrCase, thank you so much for responding. I feel good about burying the pipes and moving forward. Thanks again.
Carmen
 

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