Hi,

I bought the following pump:

Details: Self-Priming Eject Pumps
Model No.: JSP/JSW
Product Origin: China
Brand Name: YANGCHUN

Features:
1) Pump body: cast iron
2) Impeller: brass/plastic
3) Motor housing: aluminum
4) Mechanical seal: stainless steel
5) Shaft: 45# steel
6) Insulation class: B
7) Protection IP44
8) Single phase: 220V/50Hz, 110V - 127V/60Hz

I bought this pump and conected it to a water tank so i can get water in and pump water out to a tap which my drip system is connected to. If you check the picture closely, there is a 3/4" opening on top and a 3/3" opening in front and I assumed that the top opening is for WATER IN and the front opening for WATER OUT. When I start the motor, it works fine, but there is no water coming out of the tap and there is no water going back to the tank because i have a check valve between the tank and the pump.

How can I know exactly which is WATER IN and which is WATER OUT before i change the piping...?