JS RST Top Outlet Drainage Submersible Pumps 400v

Where to Use RST Three-Phase Pumps

RST pumps earn their place where a pump has to run for long periods on a 400v supply. Typical jobs include dewatering excavations, basements and lift pits on larger construction sites, draining plant room and car park sumps in commercial buildings, circulating water features, fountains and waterfalls, and transferring water for agricultural irrigation. Because the outlet is on top, the pump sits neatly in a pit or pond with the hose or pipe rising straight up from it.

Size the pump on both flow and head. Every metre of lift and every length of hose or pipe eats into the flow you actually get, so a pump that looks generous on paper can fall short at the discharge point. Our guide to reading a pump curve shows how to find the duty point for your job, and our guide to discharge pipe sizing explains why a larger hose often recovers lost flow. If the curve shows a standard model running out of head before it reaches your duty point, move to its H version.

Know the limits of the range. RST pumps handle clean and dirty water but are not sewage pumps; for foul water on a three-phase supply, look at the JST SV sewage vortex pumps. For side-outlet three-phase site pumps, see the JST and JST-H heavy duty range, and for moving very large volumes at low head in ponds and lakes, the RS/T AL propeller pumps are a better fit.

Frequently Asked Questions

What does the H mean on RST pumps?

H stands for high head. The RST-22H, 37H, 55H and 75H use the same motor sizes as the RST-22, 37, 55 and 75 but lift water higher at a lower maximum flow. For example, the RST-55 moves up to 1,670 l/min with 29 metres of head, while the RST-55H moves up to 1,155 l/min but reaches 35 metres.

Can I run an RST pump on a single-phase supply?

No. Every RST model has a 400v three-phase motor. If your site only has 110v or 230v, the JS RS top outlet pumps use the same top outlet design on single-phase motors, up to 0.75 kW.

How do I make an RST pump switch on and off automatically?

RST pumps are supplied as manual pumps with no float switch. For unattended running, wire the pump through a three-phase control panel that starts and stops it from level floats in the sump; the float signals the panel rather than switching the motor directly. Our pump controls section and the team on 01252 515169 can help you match a panel to the motor size.

Should I check the rotation on a new RST pump?

Yes. A three-phase pump wired with two phases swapped will run backwards, and a pump running backwards still moves some water but well below its rated flow and head. Have your electrician check the direction of rotation when the pump is first connected and after any change to the supply.

Which RST pump suits a water feature?

For small features and fountains, the 2-inch RST-6 or RST-8 is usually enough. Larger cascades and waterfalls that need more volume suit the RST-22 or RST-37, and if the water has to be lifted high above the pond, compare the H models. The whole range is designed for continuous duty.

If you would like help choosing an RST pump for a site, sump or water feature, call the AES Rewinds team on 01252 515169 or email sales@aesrewinds.com. You can also browse the full JS Pumps range or all drainage pumps.