Bests & Worsts Reviews from Amazon

These Zoeller pumps are virtually bombproof. I have an M53 and M98 with battery backup protecting my basement. They run very reliably and are easy to service. However, you can't just plug them in and forget about them. Here are a few things I've learned over the years. ***IMPORTANT*** The key to keeping them running forever is some periodic service. 1) SWITCH : As many have found the hard way, it's unfortunate that the switch in this pump is the weak link in an otherwise bombproof product. Luckily, this plastic switch is very easily replaced with a screwdriver ($25-part # 004892 or 004705 - don't forget a rubber gasket). They seem to last 3-6 yrs depending on the conditions used - mine activate on average every 2-3 minutes, sometimes as frequently as every 20 sec during a heavy storm. The switches in my pumps last 3-4 yrs. 2) RUBBER FLOAT LEVER BOOT: The rubber boot/seal where the float lever enters the pump cap assembly will harden over time, providing just enough resistance for the lever not to activate the pump switch (very frustrating to find the pump submerged underwater, then the slightest movement triggers the motor) - keeping this lubricated with a bit of silicone grease will help prevent or solve this problem. (Make sure not to use a petroleum based grease.) When/if it fails, the cap assembly will need to be replaced ($30 - part #004703). 3) IMPELLER/CHECK VALVE : periodically remove the base of the pump (just remove several screws) to scrape/clear out any built up debris or buildup, clear the area by the exit pipe and make sure the check valve can operate properly. 4) FLOW HOLES - there are two small holes in the pump assembly by impeller and exit pipe. These will get clogged over time and can cause an unlikely 'airlock' situation where the impeller with turn freely within a pocket of air and not push any fluids. Keeping these holes clear with a nail will prevent this condition.