PUMP SYSTEMS involve the addition of a pump chamber and a pump to a system in order to get the effluent to a leaching area that can't be fed from the tank by gravity. In other words, the leaching area is above the septic tank's outlet pipe.
A pump chamber is simply a septic tank without the baffle wall and with a larger, 24" access-manhole for the pump. The pump is installed near the bottom and cycles on and off via a float switch, keeping the level in the pump chamber low. If there's a power failure or pump malfunction the remaining capacity of the pump chamber is available to receive effluent from the tank. When this happens the rising level in the pump chamber activates a higher float switch, triggering an audible and visual alarm in the house. The sound of the alarm can be silenced with a switch on the alarm unit, but the warning light will remain on until the condition is rectified, the pump goes back on, and the level in the pump chamber returns to normal.
If a lengthy power failure causes the alarm to sound when the power comes back on, the pump should kick on and restore the normal level in the pump chamber quickly, and the alarm box light should go off. If it doesn't, check your circuit breakers, especially if the "septic pump" is on a GFI breaker. After the pump receives power the light should go off within the hour.
In the case of a pump failure, call for service by an installer or a pump company as soon as you can, as the remaining capacity of the pump chamber may only afford you two days of use without sewage backup or discharge.
The pump uses a two-inch "pressure" pipe to deliver the effluent to the leaching area. The two-inch pipe discharges into a separate "baffle box" and from there into the leaching area proper. The baffle box helps to "still" the forceful discharge from the pump.