Sometimes the fixture is lower than the drain. A bar sink in a basement, a kitchenette added to a retrofit fit-out, a cleaner's sink below the sewer line, or the outlet of a kitchen oil separator that sits under the main drain. When gravity fall isn't available, the waste has to be pumped up to a point where it can run away by gravity. That's the job of an undersink lifting station.
PSA stocks two Hyjet units for this: the Minilift 40 (HML40-A) and the Minilift 70 (HML70-A). This guide covers what separates them, how to pick a tank size, and what to plan for before you install one.
What the two units share
Going by the listings, the 40 and 70 use the same pump and the same features. The only listed difference is tank volume.
| Minilift 40 (HML40-A) | Minilift 70 (HML70-A) | |
|---|---|---|
| Tank | 40 L, 304 stainless | 70 L, 304 stainless |
| Pump | 250W submersible drainage pump, automatic float | 250W submersible drainage pump, automatic float |
| Max head | 9 m | 9 m |
| Max flow | 180 L/min | 180 L/min |
| Alarm | High level alarm included | High level alarm included |
| Other | Adjustable float start/stop levels, thermal overload protection, blockage resistant impeller | |
| Price | $1,739.05 | $2,421.05 |
So the 70 costs $682.00 more and buys you 30 litres of extra storage. No extra pumping power. That makes the choice simpler than it looks: you're paying for buffer, not performance.
Choosing 40 L or 70 L
A bigger tank does three things for you:
- It absorbs a big dump in one go. When someone pulls the plug on a full sink, that water arrives faster than any small pump moves it. The tank holds the surge while the pump catches up.
- It means fewer start-stop cycles. More litres between the float's start and stop levels means the pump runs less often for longer, which is easier on it.
- It gives you more warning time. If the pump fails or the discharge blocks, there's more volume between the high level alarm going off and water backing up into the fixture.
A quick way to size it: work out the largest single discharge the station will see. For a sink bowl, that's length × width × depth. A 500 × 400 × 250 mm bowl holds 50 litres to the brim. If the station serves only a small hand basin or a bar sink, the 40 is usually plenty. If it serves a large or double-bowl sink, a commercial cleaner's sink, or more than one fixture that might drain at the same time, lean towards the 70. When it's close, the extra buffer is cheap insurance against a call-back.
Before you commit, check that the unit physically fits the cupboard or plant space. The listings don't give dimensions. The manufacturer's datasheet, with dimensions and pump curves, is under Downloads on each product page.
Reading 9 m and 180 L/min properly
Max head and max flow are the two ends of the pump curve, not figures you get at the same time. At 9 m of lift the flow drops to almost nothing. At full 180 L/min flow there's next to no head. Every real job sits somewhere in between.
To check a job, add up the vertical lift from the unit to the highest point on the discharge line, then allow for friction in the pipe run, bends and fittings. Long horizontal runs and lots of elbows eat into what the pump can deliver. Then read the curve on the datasheet at that total head and make sure the flow there is enough for your fixtures. Don't design a job at the 9 m figure.
What it's for, and what it isn't
Hyjet describes the Minilift for clean or dirty water from sinks, kitchen oil separators and other drainage points where gravity fall isn't available. The listings don't describe it as a toilet or macerator unit, so don't connect a WC or urinal to it. Faecal waste needs a station rated for sewage.
In a commercial kitchen, the oil separator or grease arrestor goes upstream, and the Minilift lifts what comes out of it. Grease and food solids sent straight into a small pump are the fastest way to a blocked impeller and an alarm call. Fit a strainer basket at the sink outlet too. Our guide to commercial drain protection covers strainer baskets and check valves. Trade waste rules for grease arrestors are set by your local water authority, so check them before you design the system.
Install checklist
- Discharge. Install to AS/NZS 3500.2 and your local authority's rules. A non-return valve and an isolating valve on the discharge make servicing easier and stop the rising main draining back into the tank. The listings don't say whether a non-return valve is supplied, so check the datasheet or ask PSA.
- Venting. Plan the tank vent as part of the drainage design.
- Power. The pump and alarm need a suitable power supply, installed by a licensed electrician where required. Check the datasheet for how the alarm is powered and whether it's audible, visual or both.
- Access. Leave room to lift the unit out, clean the tank and adjust the float. Undersink units get forgotten until they alarm.
- Floats. Set the start and stop levels to suit the tank and the inflow. Too narrow a band means short cycling.
- Certification. The listings don't show a WaterMark licence number. If your job or certifier requires a WaterMark-certified lifting station, confirm with PSA before ordering.
Both units are listed as available to order on backorder. Contact PSA to confirm lead time if the job has a deadline. You can see both side by side in the Lifting Stations & Undersink Pumps collection, or browse the wider Pumps range. If the lift station is going under a vanity or kitchen sink, our space saver traps guide can help you get cupboard room back.
Frequently Asked Questions
What's the difference between the Hyjet Minilift 40 and Minilift 70?
Tank size. The HML40-A has a 40 litre tank and the HML70-A has a 70 litre tank. Both use a 250W submersible pump with 9 m max head, 180 L/min max flow, an automatic float and a high level alarm.
Can I connect a toilet to a Hyjet Minilift?
No. Hyjet describes the Minilift for water from sinks, kitchen oil separators and other drainage points. It isn't described as a toilet or macerator unit, so use a sewage-rated lifting station for WCs.
Will the Minilift pump 9 metres high?
9 m is the maximum head, where flow drops to almost nothing. Add up your vertical lift plus friction losses in the pipe and fittings, then check the flow at that head on the pump curve in the datasheet.
Does the Minilift have an alarm?
Yes. Both models include a high level alarm, which warns you before the tank overflows if the pump fails or the discharge blocks. Check the datasheet for how the alarm is powered.