Step 5 · Prepare and Pre-charge the New Tank
Before installing the new tank, you must set its internal air pressure. Locate the air valve on top of the tank, which looks like a tire valve stem. Use a tire pressure gauge to check the factory pre-charge. It must be set to 2 PSI *below* your pump's cut-in pressure. For a 30/50 PSI switch, the cut-in is 30 PSI, so you must set the tank's pre-charge to 28 PSI. Use an air compressor or bicycle pump to add air, or press the pin in the valve to release air until you reach the correct pressure. The tank must be empty of water when you perform this check.