Sump pit requirements
The Zoeller M53 and M98 require a sump pit of minimum 18-inch inside diameter (24 inches recommended for M98 with wide-angle float). The pit depth should be minimum 24 inches below the basement floor for adequate water volume before pump activation. Install a pit liner (perforated ABS or polypropylene liner) if the pit is in soil -- the liner prevents soil intrusion into the pump. The pump sits on the pit floor -- if the floor is uneven, use flat concrete blocks to level the pump base.
Discharge line installation
Connect a 1.5-inch PVC pipe to the pump's 1.5-inch NPT discharge port using a threaded PVC adapter and pipe cement. Install a check valve immediately above the pump on the vertical discharge run -- the check valve prevents backflow from the discharge pipe back into the pit when the pump stops, which would require re-pumping the same water repeatedly. The check valve must be installed in the vertical section. Run the discharge line out of the foundation and to daylight at least 6 feet from the foundation wall -- discharging closer allows water to re-infiltrate. Do not discharge to a sanitary sewer (illegal in most jurisdictions -- check local code).
Float switch clearance
After placing the pump in the pit, verify the float switch can move freely without contacting the pit wall. M53 ball float: the float arm should be able to swing upward through 45 degrees without obstruction. M98 wide-angle float: requires 6-8 inches of clear space around the float. N98 vertical float: requires 3-4 inches of clear space around the vertical float rod. If the float contacts the pit wall, the pump will not activate correctly. Adjust the pump position or trim the float tether if needed.
Electrical requirements
All Zoeller M-series pumps require a dedicated 115V, 15A circuit with GFCI protection (required by the NEC for wet locations). Do not plug into a multi-outlet strip or extension cord -- single-outlet dedicated GFCI. The pump cord is 10 feet -- if the outlet is more than 10 feet from the pit, have an electrician extend the circuit rather than using an extension cord. Test GFCI protection monthly. Zoeller recommends an annual pump test: manually activate the float switch by lifting it while the pump is submerged and verify it moves water through the discharge line.