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Sump pump question please.

Posted by edweather (My Page) on
Wed, May 15, 13 at 12:16

Just replaced our sump pump with the exact same model as the old one. It has a 1 1/2" NPT discharge. The instructions to the new pump say NOT to use a discharge pipe smaller than the pump discharge. The hose adapter on the old pump is threaded into the old pump discharge, but when I looked down inside the discharge, the actual opening in the adapter is 7/8". We didn't install the original pump, but it looked professionally installed when the pit was made. The old adapter is seized in the old pump and is plastic, so I don't want to break it trying to remove it. The new pump didn't come with an adapter, but I found a 1 1/2" adapter in my pool supplies, with a similar 7/8" opening. Is that ok to use? Or should I go to the store and look for a TRUE 1 1/2" discharge adapter? Thanks in advance. Ed. The photo is of the old pump and adapter. I should also mention that it discharges into a 1 1/2" PVC pipe.


Follow-Up Postings:

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RE: Sump pump question please.

I'm no expert, but if the new pump says that you need 1-1/2" discharge or larger, then that is what you need.

You last sentence is confusing - if you are going to 1-1/2" PVC, why is there a reducer out of the old pump? At what point does it go back up to 1-1/2"


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RE: Sump pump question please.

The 1 1/2" pipe connects to the larger diameter flange you see above the 7/8" reducer. The 7/8" reducer is down inside the adapter/flange. I was as surprised as you when I looked down inside and saw the smaller opening. It worked fine for about 15 years. But like you say if the directions say to use a 1 1/2 " discharge....

That's why I'm asking the question.


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