This sounds like it might be a classic symptom of air-lock. The "weep" hole as it is called should always be drilled in your discharge pipe to prevent an air-lock. This is true in sump and sewage applications. Air locking on a sump pump happens when there is air between the pump and the check valve of the discharge line. The trapped air prevents the impeller from drawing in enough fluid to open the check valve to allow discharge. The weight of the fluid on the topside of the check valve keeps it closed.

The problem is often noticed after the initial use when the pit has had time to dry out during a dry spell. When it gets water in the pit again, the air-lock condition shows up. The pump runs due to the float switch being raised, but can't eject the water because of the air-lock condition. I suggest that you drill a 1/8" or 3/16" hole in your PVC discharge pipe, approximately 4" above your pump's discharge port and well within the inside of the basin. Drill the hole at a 45-degree angle so the hole is pointing toward the bottom of your sump basin. Water will be discharged from the weep hole when your pump operates. This is completely normal.

A typical installation will have the check valve positioned about 2-3 feet above your sump basin cover. If the check valve is screwed directly into the sump pump's discharge port, there is really no place to drill the weep hole, but also less of a chance of air-lock due to the positioning of the check valve. The only problem with installing the check valve directly into the pump's discharge port is that it takes more power and effort for the pump to start due to the added weight of all the water sitting above that check valve, especially if your head is 8 feet or higher. When the check valve is installed above the basin cover, it reduces that starting power and also makes for a much easier method of replacing or performing maintenance on your pump and system. If this was done and you are still having problems, I would suggest calling Zoeller tech support at 800-928-7867 for troubleshooting assistance.

Paul,

I would highly suggest reaching out to Zoeller directly. You can reach them at (800) 928-7867.

Typical installations will include the discharge PVC Sch40 pipe screwed into the pump discharge port and extending approximately 2-3 feet above the sump basin cover. At this point, you could attach the check valve and then complete your discharge configuration. This method would allow for an easier access point for you to service your pump.

If your catch basin is at least 18" wide by 24" deep, you might consider the Zoeller model M53 1/3HP Sump Pump or the 1/2HP model M98. The N53 model is a NON-AUTOMATIC pump and would not activate without the help of some type of float switch. The M53 & M98 both include a vertical float switch to activate and deactivate the pump. As long as you can filter debris like leaves and twigs from getting into the pump, you should be fine.

The only maintenance that is required is what all manufacturers recommend. And that is to inspect your pump, float switch and sump basin every 4-6 months to insure that they are operating properly and there is no debris in your basin that could impede the pump or float switch operation. Oil should NOT need to be added at any time unless the pump develops a leak which is pretty rare. If that should happen, it's usually easier to have it serviced at a local authorized Zoeller service center or replace the pump.

Without knowing more specifics like the water table, area of the country you live in, actual square footage of your basement, etc., it really is difficult to answer. I can tell you that most average sized homes in an average water table area can usually get away with a 1/3HP or 1/2HP pump. Beware of over-sizing the pump as it could cause the pump to cycle too frequently thereby reducing the life of the pump. You don't want to just install a 3/4HP or 1HP pump just for the sake of it.