A standard pressure pump runs flat out whenever it's on. Its pressure controller switches it on when pressure drops and off when flow stops, so the pressure at the shower rises and falls as other taps open and close. A variable speed drive (VSD) pump works differently. A pressure transducer on the outlet tells the drive what the pressure is, and the drive speeds the motor up or slows it down to hold a set pressure, whether one tap is open or six.
That gives you steadier pressure, a softer start and stop, and a pump that only uses the power the demand needs. It also costs roughly twice as much as a fixed-speed pump of the same size. This guide covers when that premium is worth paying and which of the VSD pressure pumps PSA stocks suits which job.
What the premium actually is
The clearest comparison is the same pump body sold both ways. These are listed prices for the fixed-speed version and its VSD equivalent:
| Fixed-speed pump | Price | VSD version | Price | Difference |
|---|---|---|---|---|
| Hyjet HCM2-40 (550W) | $941.55 | HCE2-40 (550W, 3L tank) | $2,157.05 | $1,215.50 |
| Hyjet HCM4-60 (1100W) | $1,189.05 | HCE4-60 (1100W, 3L tank) | $2,344.05 | $1,155.00 |
| Hyjet HM3-5 (0.75kW, pump only) | $1,211.05 | HM3-5-E1 (with E1 drive and 8L tank) | $3,284.55 | $2,073.50 |
| Hyjet HM9-5 (1.85kW, pump only) | $2,003.05 | HM9-5-E1 (with E1 drive and 8L tank) | $4,021.55 | $2,018.50 |
So on a household-sized pump you're paying somewhere between about $1,150 and $2,100 extra for variable speed. The question is whether the job needs what that buys.
When VSD is worth it
- Several outlets running at once. In a house with three or four bathrooms on tank water, a fixed-speed pump gives the first shower full pressure and lets it sag when the next one turns on. A VSD pump holds the setpoint across both.
- Multi-storey buildings. The pump has to overcome the height to the top floor plus friction, and a steady discharge pressure matters more the further the water travels.
- Long running hours. Irrigation, wash bays and process water where the pump runs for long periods at part load are where slowing down to match demand saves the most energy.
- Noise-sensitive installs. A pump running at the speed it needs is quieter than one cycling at full speed, which helps when it's next to a bedroom or in a shared plant room.
For a small house with one or two bathrooms, a fixed-speed pump with a good pressure controller is usually fine. See our guide to multistage vs jet pumps for the fixed-speed options.
The three Hyjet VSD ranges
HCE series: compact horizontal VSD pumps
The HCE uses a pressure transducer on the outlet and a built-in drive. The smaller HCE2-40 (550W, 58 L/min max flow) and HCE4-60 (1100W, 116 L/min) are 240V and come with a 3L pressure tank, which suits tank-fed houses and small commercial jobs. The larger HCE10 and HCE12 models list flow in cubic metres per hour: the HCE10-40 is 1.5kW, 10 m³/h at 37m rated head; the HCE10-50 is 2.2kW, 10 m³/h at 46m; and the HCE12-25 is 2.2kW, 12 m³/h at 33m. Those 2.2kW models come in 240V or 415V three phase (the T suffix). The listings rate the motor for continuous duty.
HM-E1: horizontal multistage with a separate E1 drive
The HM-E1 pairs a stainless HM multistage pump with an Italian-made E1 variable speed drive and an 8L pressure tank. It's listed in 0.75kW (80 L/min max), 1.85kW (170 L/min) and 1.85kW (240 L/min) versions, all 240V, with a maximum operating pressure of 8.5 bar. It's the step up from the HCE when you want the larger HM pump body and a drive that's separate from the motor.
HMV series: vertical multistage for plant rooms
The HMV is a stainless 304 vertical multistage pump made in Italy by Pentax, supplied with its matched E-series drive. The vertical footprint suits plant rooms where floor space is tight. The range runs from the HMV3-7-E1 (1.1kW, 240V) to the HMV18-9-E318 (6.6kW, 400V three phase). Liquid temperature is listed as -15 to 110°C, and maximum operating pressure as 8.5 bar for pumps with up to 6 impellers or 14 bar for 7 or more. Maxijet lists the range as AS4020 certified for contact with drinking water. If you need two pumps for redundancy, the same pumps come assembled as booster sets.
Before you order
- Work out the duty point. You need the flow at peak demand and the pressure required at the furthest or highest outlet. Check both against the pump curve in the datasheet under Downloads, not just the maximum flow and head in the title.
- Check the supply. The larger HMV and HCE models need 400V or 415V three phase. Confirm what's available on site before you choose, and have a licensed electrician connect hard-wired and three phase equipment.
- Don't run it dry. These pumps are for clean water. Fit a strainer on the suction side and protect against running dry, especially when drawing from a tank.
- Isolation and non-return valves. Plan isolating valves on both sides of the pump for servicing and a non-return valve on the discharge.
Replacing just the drive on an existing pump? Our guide to choosing a VSD pump controller covers matching a drive to the motor. All of these pumps are available to order on backorder; contact PSA to confirm lead time.
Frequently Asked Questions
What does a VSD pressure pump do differently?
A VSD pump changes its motor speed to hold a set pressure as demand changes. A fixed-speed pump runs at full speed whenever it's on, so pressure varies as taps open and close.
How much more does a VSD pump cost?
Comparing the same Hyjet pump sold both ways, the VSD version costs between $1,155.00 and $2,073.50 more at listed prices for household-sized pumps.
Do I need three phase power for a VSD pump?
Not for the smaller models. The HCE2-40, HCE4-60, HM-E1 range and smaller HMV models are 240V. The larger HMV models and the HCE T models need 400V or 415V three phase.
Is a VSD pump quieter?
Usually, yes. Because it runs only as fast as the demand needs, it spends less time at full speed than a fixed-speed pump and starts and stops more softly.