Grundfos Unilift AP Wastewater Pump

UNILIFT AP35 is a single-stage submersible pump for drainage water and effluent — dirty water and untreated wastewater excluding toilet discharge, and liquids containing fibres from light industry and laundries, with particles up to 1.4 in. UNILIFT AP50 handles the same duties plus domestic wastewater with or without discharge from water closets, with particles up to 2.0 in.

On AP35 and AP50 the stainless-steel pump sleeve is made in one piece with an insulated carrying handle, and the inlet strainer clips onto the pump housing for easy removal. The housing carries an internal riser pipe for high efficiency, perforated to cool the motor during operation, and the cable entry uses a socket and plug connection for quick dismantling. AP35 has a 1-1/2 in NPT vertical outlet; AP50 has a 2 in NPT vertical outlet.

The B models — AP35B and AP50B — use a different housing: a steel tube with a smooth surface and a hydraulically correct shape that gives free passage of particles and a higher head. The ring stand, pump inlet and pump housing are fastened to the motor by four springs for quick dismantling, and the outlet is a threaded 2 in NPT horizontal port, which suits installation on an auto coupling. Liquid temperature on the B models is limited to 104 °F against 131 °F on AP35 and AP50.

All four use a stainless-steel vortex impeller with L-shaped backswept blades and a protective cap that prevents the deposit of long-fibered material. The shaft runs in maintenance-free prelubricated ball bearings; the shaft seal combines a mechanical bellows seal and a lip seal with an oil chamber between, with silicon carbide faces. Motors are single-phase asynchronous dry-rotor motors with built-in thermal protection, IP68 enclosure and class F insulation. The pumps are not designed for continuous operation.

• Vortex impeller with protective cap — backswept L-shaped blades keep solids moving and stop long fibres depositing on the impeller.
• Real solids handling — 1.4 in free passage on AP35 and AP35B, 2.0 in on AP50 and AP50B, so toilet discharge is within reach of the AP50 pair.
• Two housings, two installation styles — AP35 and AP50 are free-standing with a vertical outlet and clip-on strainer; AP35B and AP50B use a smooth steel-tube housing with a horizontal outlet and a ring stand suited to auto coupling.
• Spring-mounted wet end on the B models — ring stand, pump inlet and housing fasten to the motor with four springs and come apart quickly for service.
• Silicon carbide shaft seal — mechanical bellows seal and lip seal with an oil chamber between them.
• Manual or automatic — automatic (A) builds carry an integral float switch and start and stop on level; manual builds run on an external level control or panel.
• Built-in thermal protection, IP68 enclosure, insulation class F, CSA C/US.

• Groundwater lowering
• Pumping in drainage collecting tanks
• Pumping in surface water collecting tanks fed from roof gutters, shafts and tunnels
• Emptying of ponds, tanks and containers
• Fibre-containing wastewater and effluent from laundries and light industry
• Domestic effluent from septic tanks and sludge-treating systems
• Effluents from viaducts and underpasses; ditch drainage water; pool water
• Domestic wastewater without discharge from water closets — all four models
• Domestic wastewater with toilet discharge below sewer level, outdoor installations — AP50 and AP50B only

Automatic models carry an integral float switch (the A in the type designation); manual models (.1V) have no level switch and run whenever they are energised, so they need an external float or control panel. All models ship with 25 ft of cable and no plug — they are wired in on site at 230 V. The free cable length between the float switch and the pump handle sets the start/stop difference: longer means fewer starts and a larger level swing, shorter means more frequent starts and a smaller swing. Minimum free cable length is 4 in.

Order by the part number in the Models table above.