A sewage pump has to move water with solids in it: rags, wipes, grease and whatever else gets flushed. What it can pass, and how efficiently it pumps, comes down mostly to the impeller. This guide covers the four impeller types in the vortex and sewage pump range and how to choose between them.
The four impeller types
Vortex and set-back vortex
A vortex impeller sits recessed back from the flow. It spins the water into a whirlpool and most solids pass through without touching the impeller. That makes it the most clog-resistant design, at the cost of some efficiency. A set-back vortex recesses the impeller even further for the heaviest solids.
- Hyjet HWV (50mm and 65mm, 0.75kW to 4.0kW): a semi-open vortex impeller that passes soft or fibrous solids up to 70% of the discharge size, per the listing.
- Hyjet DV (65mm to 100mm, 1.5kW to 5.5kW): heavy-duty set-back vortex for civil and industrial drainage, with solids handling up to 45–50mm, 20m maximum submersion and a guide rail option (DGRK).
- Hyjet DG (made by Pentax in Italy): DG80-1A (1050W, 250 L/min, 8m), DG100 (1350W, 300 L/min, 10m) and DG150 (1550W set-back vortex, 600 L/min, 11m), with free passage of 35mm or 50mm depending on model.
Enclosed channel
An enclosed channel impeller has shrouds on both sides of the vanes, forming closed channels. It's more efficient than a vortex, so it can push wastewater further and higher for the same power, which suits long-distance transfer. It's less tolerant of long fibrous material than a vortex.
- Hyjet HWE (50mm, 65mm and 80mm, 1.1kW to 4.0kW): HT200 cast iron body, stainless shaft, double silicon/carbon mechanical seals, heavy-duty ball bearings and a 5m maximum immersion. Listed for sewage, stormwater and trade waste and suited to long-distance transfer. Guide rail kits (HGRK) are available for all models.
Double channel
A double channel impeller has two wide passages, giving a balance between solids passage and efficiency.
- Pedrollo BCm 15/50 (1.1kW, 750 L/min) and BCm 10/50-ST (stainless, 0.75kW, 600 L/min): pass solids up to 50mm, 5m maximum submersion, manual or float switch.
- Hyjet DB100 (1350W, 600 L/min, 11m head): stainless shell, motor cover and impeller, double mechanical seal with an oil barrier.
How to choose
- Lots of rags, wipes or fibrous waste: vortex or set-back vortex. Clog resistance matters more than efficiency.
- Long or high discharge run: enclosed channel, which turns more of the motor's power into head and flow.
- Mixed wastewater and dirty water in a sump: double channel is a good middle ground.
- Small-bore pressure discharge: none of these. A grinder pump macerates solids so they fit a small pipe.
Discharge size and supply
Discharge size (50mm, 65mm, 80mm or 100mm) sets the pipe you connect to and roughly how large a solid will pass. Match it to the discharge line your design calls for. On supply, many HWE, HWV and DV models are 415V three phase only, while smaller models come in 240V single phase. A licensed electrician must connect hard-wired and three phase equipment.
Installation
- Guide rails: for pump stations deeper than you can safely reach, a guide rail kit lets you lift the pump out for service without anyone entering the well.
- Duty and standby: many commercial stations use two pumps so one can run if the other fails.
- Alarms: fit a high level alarm to every sewage pit.
- Compliance: sewage pumping must be installed by a licensed plumber to AS/NZS 3500.2 and your local authority's requirements.
For stormwater and greywater rather than sewage, see our guide to choosing a drainage or sump pump. All the pumps above are available to order on backorder; contact PSA to confirm lead time.
Frequently Asked Questions
What's the most clog-resistant sewage pump impeller?
A vortex or set-back vortex impeller. It sits recessed from the flow, so most solids pass without touching it.
When should I choose an enclosed channel sewage pump?
When the wastewater needs to travel a long way or a significant height. Enclosed channel impellers are more efficient than vortex impellers, so they deliver more head and flow for the same power.
Do sewage pumps need three phase power?
Larger models usually do. Many Hyjet HWE, HWV and DV models are 415V three phase only, while the smaller models come in 240V single phase.
Do I need a guide rail kit for a sewage pump?
In a deep well, yes. A guide rail lets the pump be lifted out for service without anyone entering the well.