The FEDCO MSS is a multistage centrifugal high-pressure feed pump used on small and mid-size seawater RO plants. Meliora sources MSS spare parts and complete replacement pumps from FEDCO, matched to the nameplate of the pump in service.
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In short: The FEDCO MSS series has eleven models, MSS-15 to MSS-240, covering 7.5 to 295 m³/h at pressures up to 83 bar. The bearings are lubricated by the pumped water, so the pump uses no oil or grease. Meliora sources MSS parts and complete pumps from FEDCO against the full nameplate data.
| Model | Flow range (m³/h) |
|---|---|
| MSS-15 | 7.5–20.5 |
| MSS-20 | 10–34 |
| MSS-30 | 15–45 |
| MSS-40 | 20–51 |
| MSS-55 | 27.5–77 |
| MSS-75 | 37.5–105 |
| MSS-90 | 45–124 |
| MSS-120 | 60–132 |
| MSS-160 | 80–193 |
| MSS-200 | 100–250 |
| MSS-240 | 120–295 |
Source: FEDCO MSS high-pressure feed pump flyer. Maximum pressure 83 bar (1,200 psi). FEDCO also offers a high inlet pressure option to 70 bar.
| Item | FEDCO MSS |
|---|---|
| Pump type | Multistage centrifugal |
| Thrust bearing | FEDCO Water Bearing, lubricated by the pumped water |
| Shaft bearings | Product-lubricated |
| Lubrication | No oil or grease required |
| Shaft seal | Mechanical cartridge seal, operating at low pressure |
| Materials | Duplex and super duplex stainless steel pressure parts, 316L stainless steel impellers and diffusers |
| Motor | 2-pole, NEMA or IEC |
| Coupling | Flexible disc type |
| Maximum efficiency | 80% |
| Warranty stated by FEDCO | 18 months |
Source: FEDCO MSS product page and flyer.
The feature that defines the MSS is its bearing arrangement. A conventional multistage pump carries its axial thrust on oil-lubricated bearings at the end of the shaft, which need an oil system and regular attention. FEDCO puts a water-lubricated thrust bearing inside the pump and uses the pumped water to lubricate the shaft bearings as well. The benefit is less maintenance. The condition is that the pump must never run dry and the feed water must be properly filtered, because the bearings depend on that water.
The model, for example MSS-15, gives the hydraulic size. It does not say how many stages the pump has, and the number of stages is what sets the pressure. Two MSS-15 pumps on different plants can have different stage counts and therefore different shafts, casings and part quantities. The motor speed matters too: the same pump on 50 Hz and 60 Hz supplies runs at different speeds and delivers different duties.
FEDCO identifies the build from the serial number. Where a serial number is missing or was never recorded properly, the operating data lets FEDCO work back to the correct pump.
Copy the nameplate in full, or send a photo. For an MSS pump we need:
If you are replacing a complete pump, say whether the existing motor and baseplate are being kept. A bare pump to fit an existing motor is a different order from a complete pump set.
FEDCO’s larger feed pump is the MSD series, which covers 40 to 1,080 m³/h. See FEDCO MSD pump parts. FEDCO’s energy recovery turbochargers are covered on the FEDCO HPB page, and the full range on the FEDCO overview.
MSS feed pump out of service? Send the nameplate. Plant-down enquiries get a reply within 4 hours, standard quotations within 48 hours.
Page reviewed October 2026 · Meliora FZCO, Dubai Silicon Oasis, UAE
The MSS series covers 7.5 to 295 cubic metres per hour across eleven models, from the MSS-15 at 7.5 to 20.5 cubic metres per hour to the MSS-240 at 120 to 295. Maximum pressure is 83 bar, or 1,200 psi.
FEDCO lists the MSS-15 with a flow range of 7.5 to 20.5 cubic metres per hour.
No. The MSS uses a water-lubricated thrust bearing and product-lubricated shaft bearings, so no oil or grease is required. The bearings rely on the pumped water, so the pump must not be run dry.
The model and serial number, the rated flow and pressure, and the motor power, speed, frequency and voltage from the nameplate, with the feed water salinity. The number of stages differs between pumps of the same model, so the model on its own does not identify the parts.
Both are multistage high-pressure feed pumps for reverse osmosis. The MSS covers 7.5 to 295 cubic metres per hour. The MSD is the larger series, covering 40 to 1,080 cubic metres per hour.