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.