JS GST Grinder Sewage Submersible Pumps
The JS GST grinder sewage submersible pump range is the three-phase, 400v version of the JS grinder design, for sites with a three-phase supply that need to pump sewage to a high or distant discharge point. A rotating cutter working against a high-chrome grinder ring shreds soft solids before they reach the impeller, so the waste can be pumped through small-bore pipe instead of a large-bore gravity drain or rising main.
There are four models, from 1.2 kW to 3.7 kW. JS Pumps lists them for domestic and industrial jobs where high heads or long distances rule out a standard submersible, or where large-bore discharge pipe is not available or too costly to lay. The pump body, impeller and motor covers are cast iron, the motor case and shaft are stainless steel, and the mechanical seals are silicon carbide and carbon. Each pump can stand free or be mounted on a guide rail.
Choosing a GST model
The number in the name is the motor size: GST-12 is 1.2 kW, GST-15 is 1.5 kW, GST-22 is 2.2 kW and GST-37 is 3.7 kW. The range splits into two outlet sizes.
1¼” models (GST-12 and GST-15). These deliver up to 190 litres per minute, with maximum heads of 19 and 22 metres. They suit a single property, annexe or small commercial building on a three-phase supply, pumping through 32 mm pipe.
2″ models (GST-22 and GST-37). These move up to 320 and 330 litres per minute. The GST-22 reaches 23 metres and the GST-37 36 metres, the highest head in the range, for long rising mains, steep discharge routes and busier sites.
Control. GST pumps are bare pumps with no float switch, so they run under a three-phase control panel with level control. If you only have a single-phase supply, the JS GS grinder range offers 110v and 230v models.
| Model | Supply | Outlet | Motor (kW) | Max Flow (l/min) | Max Head (m) | Code |
|---|---|---|---|---|---|---|
| GST-12 | 400v 3 phase | 1¼” | 1.2 | 190 | 19 | 020-712 |
| GST-15 | 400v 3 phase | 1¼” | 1.5 | 190 | 22 | 020-715 |
| GST-22 | 400v 3 phase | 2″ | 2.2 | 320 | 23 | 020-720 |
| GST-37 | 400v 3 phase | 2″ | 3.7 | 330 | 36 | 020-737 |
Maximum flow is at zero head and maximum head is at zero flow, so a working pump delivers less of each. Click through to any model for its performance curve and full specifications.
Showing all 4 results
190 l/min · 19 m · 400v
Three-phase 400v submersible sewage grinder pump with a 1.2 kW motor and 1¼" outlet. Up to 190 l/min and ...Read More£652.87 +VAT
190 l/min · 22 m · 400v
Three-phase 400v submersible sewage grinder pump with a 1.5 kW motor and 1¼" outlet. Up to 190 l/min and ...Read More£797.08 +VAT
320 l/min · 23 m · 400v
Three-phase 400v submersible sewage grinder pump with a 2.2 kW motor and 2" outlet. Up to 320 l/min and ...Read More£992.35 +VAT
330 l/min · 36 m · 400v
Three-phase 400v submersible sewage grinder pump with a 3.7 kW motor and 2" outlet. Up to 330 l/min and ...Read More£1,178.65 +VAT
Where to Use JS GST Grinder Pumps
A three-phase grinder pump makes sense when the building already has a 400v supply and the sewage has to travel uphill or a long way to reach the sewer. Typical jobs include farm buildings, workshops and small commercial premises below the level of the public sewer, a house or annexe on a three-phase supply with a long run to the nearest manhole, and package sewage stations. JS Pumps also lists process works handling waste water with organic solids, farm waste pumped to a mains sewer or treatment works, and portable sewage pumping among the uses for this design.
Size the pump on the total head at the flow you need. That is the vertical lift plus the friction loss in the pipe, which builds up quickly on long runs of small-bore pipe. Our guides to pump head and flow rate and reading a pump curve explain both, and how a sewage grinder pump works covers the cutting system. If your discharge point is close and only a few metres up, a vortex pump such as the JS JST-SV 400v sewage range passes solids whole and has no cutter to wear. For heads beyond 36 metres, look at the Pentax DTR and DTRT high head grinder pumps, and the Oliju SGR grinder range is another option to compare.
Frequently Asked Questions
Is there a single-phase version of the GST grinder pump?
Yes. The GST-12 and GST-15 are the three-phase versions of the GS-1200 and GS-1500, which come in 230v and, for the GS-1200, 110v. See the JS GS grinder range. The 2″ GST-22 and GST-37 are three-phase only.
Should I choose a 1¼” or a 2″ GST pump?
The 1¼” GST-12 and GST-15 deliver up to 190 l/min and suit a single building on small-bore pipe. The 2″ GST-22 and GST-37 move up to 320 and 330 l/min, so pick one of these for a larger inflow, a busier site or a longer rising main. The GST-37 is the choice when the total head approaches 30 metres or more.
Do GST pumps come with a float switch?
No. They are bare three-phase pumps, so they need a control panel to start and stop them, normally with float switches for level control. Our float switch guide covers the options. A high-level alarm is a sensible addition on any fixed sewage sump.
Why choose a grinder rather than a vortex sewage pump?
A grinder shreds solids so they can pass through small-bore pipe at high head. A vortex pump lets solids through whole, which needs a larger-bore discharge and generally works at lower heads. For a short, low lift into a nearby drain, a vortex pump is usually the simpler option.
What should not go into a GST grinder pump?
The cutter is designed for soft solids in sewage. Sand, gravel, stones and builders’ waste wear or jam it, so keep site run-off out of the sump. These pumps are also not for oils, solvents, chemicals or flammable liquids.
Can a GST pump be fitted on a guide rail?
Yes. JS Pumps offers every GST model either free standing or guide rail mounted, so the pump can be lifted out of a chamber for servicing without disconnecting the pipework.
If you would like help choosing a GST pump for a particular head, pipe run or control setup, call the AES Rewinds team on 01252 515169 or email sales@aesrewinds.com. You can also browse all sewage pumps or the full JS Pumps range.
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