Every RWO OWS-COM bilge water separator is fed by an AEP eccentric screw pump, which RWO's manuals also call the oil-separation pump, the eccentric spiral pump or the single outlet pump. When it loses suction or the gland leaks, you need the right part, often from a manual that still shows old part numbers.
This guide is for chief engineers, superintendents, purchasing staff and resellers. It covers the five pump types in RWO's AEP documentation: AEP 1, AEP 2, AEP 4-2, AEP 5-2 and AEP 6-2. All of it comes from RWO's own manuals (see References).
N&P Maritime has been RWO GmbH's Singapore partner since 2016, supplying genuine RWO spare parts and systems, and genuine Deckma Hamburg OMD parts sourced through RWO. We are a supply company and do not provide onboard service.
If you already know the part you need, go straight to the part-number table or send us an enquiry.
What the AEP pump is and why its parts wear
The AEP is a displacement pump: a rotor (the eccentric screw) turns inside a fixed stator, driven through a stub shaft and a cardan shaft, and a packed stuffing box seals the shaft. The rotor and stator are always in sliding contact, the cardan joints carry the rotor's eccentric motion, and the packing runs on the stub shaft. RWO's manuals give no replacement interval in hours, so these parts are replaced on condition.
Which AEP pump is on your OWS-COM?
Each OWS-COM size uses one AEP pump type, and the stator is different for each one.
Systems built to a special version can differ from the standard lists, so RWO asks for "data regarding any special version of the system" [2, p. 59]. If your pump's type plate shows a type other than these five, send us its details and the separator serial number.
Signs a part is due
Low suction, leakage and noise are not always caused by worn parts. RWO's manuals list causes to rule out first, such as air leaks, a blocked suction line, closed valves, foreign objects or the wrong rotation direction. The chart shows what to check and which part each symptom points to.
Follow RWO's AEP operating instructions for dismantling and fitting. RWO states that "pumps supplied by us may only be opened or modified by us or one of our authorised service workshops during the warranty period" [1, p. 3].
The AEP spare-part packages explained
RWO groups the pump's wear parts into four numbered packages and sells the stator and the gland packing as separate items. The numbers on the drawing are RWO's item (position) numbers, which also appear in the "Pos." column of the OWS-COM spare-parts lists, e.g. "402 (AEP)" [2, pp. 60–66].
The stator (item 402) is not in any package. If both the stator and the rotor need replacing, order the stator plus package No.3.
| Item | Name in RWO’s parts list | No.1 Shaft | No.2 Cardan shaft (coupling rod) | No.3 Rotor | No.4 Stuffing box (gland) |
|---|---|---|---|---|---|
| 125 | Shaft | 1 | – | – | – |
| 123 | Grooved pin (AEP 1, AEP 2) / clamping set (AEP 4-2, AEP 5-2, AEP 6-2) | 1 | – | – | – |
| 207 | Stuffing box packing | 1 | – | – | 1 |
| 307 | Cardan shaft | – | 1 | – | – |
| 401 | Rotor | – | – | 1 | – |
| 301 | Joint bolt | 1 | 2 | 1 | 1 |
| 303 | Casing for joint bolt | 2 | 4 | 2 | – |
| 304 | Joint housing | 1 | 2 | 1 | – |
| 302 | Joint housing (“guide bush” in newer RWO documents) | see note 1 | see note 2 | – | – |
| 306 | Clamp | 2 | 4 | 2 | – |
| 308 | Joint collar | 1 | 2 | 1 | – |
| 203 | Stuffing box cover | – | – | – | 1 |
| 204 | Stuffing box housing | – | – | – | 1 |
| 201 | Stud bolt | – | – | – | 2 |
| 202 | Self-locking nut | – | – | – | 2 |
| 402 | Stator: not in any package. Order it separately (stator + package No.3 when both stator and rotor are worn). | ||||
Part numbers by OWS-COM size
RWO renumbered its spare parts in 2017; the OWS-COM manual's 9th print records "Item numbers updated" [2, p. 2]. Many manuals on board still show the old numbers, so the table gives both.
| OWS-COM size (m³/h) | Pump | Stator item 402 | Packing item 207 | Package No.1 shaft (125) | Package No.2 coupling rod (307) | Package No.3 rotor (401) | Package No.4 gland (203) |
|---|---|---|---|---|---|---|---|
| 0.1 / 0.25 | AEP 1 | PUSPCS324814old 5460402EP1 | PUSPCS325818old 5460207EP1 | SPSVPU318066old 5500125EP1 | SPSVPU318106old 5500307EP1 | SPSVPU318110old 5500401EP1 | SPSVPU318116old 5500203EP1 |
| 0.5 / 1.0 | AEP 2 | PUSPCS324815old 5460402EP2 | PUSPCS325818old 5460207EP1 | SPSVPU318066old 5500125EP1 | SPSVPU318106old 5500307EP1 | SPSVPU318111old 5500401EP2 | SPSVPU318116old 5500203EP1 |
| 2.5 | AEP 4-2 | PUSPCS324817old 5460402EP4 | PUSPCS325818old 5460207EP1 | SPSVPU318069old 5501125EP4 | SPSVPU318107old 5500307EP4 | SPSVPU318113old 5500401EP4 | SPSVPU318118old 5501203EP4 |
| 5.0 | AEP 5-2 | PUSPCS324794old 5460402EP5 | PUSPCS325818old 5460207EP1 | SPSVPU318069old 5501125EP4 | SPSVPU318107old 5500307EP4 | SPSVPU318114old 5500401EP5 | SPSVPU318118old 5501203EP4 |
| 10.0 | AEP 6-2 | PUSPCS324818old 5460402EP6 | SESFED318422old 5461207EP6 | SPSVPU318070old 5501125EP6 | SPSVPU318109old 5501307EP6 | SPSVPU318115old 5500401EP6 | SPSVPU318120old 5501203EP6 |
- Shared parts. AEP 1 and AEP 2 share packages No.1, No.2 and No.4, and so do AEP 4-2 and AEP 5-2. Packing PUSPCS325818 fits AEP 1 to AEP 5-2. The stator and rotor package differ for every pump type.
- Items with old numbers only. The AEP appendix also lists the pump housing (item 505), the end connecting piece (item 504), pliers for clamps (5460606EP1) and joint oil in a 100 ml bottle (5460305EP0). They are not in the 2017 lists; we check availability with RWO for each enquiry.
- Complete pumps. For a complete pump (position 14), RWO's lists say "Specify voltage and frequency" [2, pp. 60–66].
For other RWO and Deckma parts, see our part number reference and parts inventory. We do not stock every part; uncommon parts are ordered from RWO, so ask us for availability and lead time.
Why RWO specifies genuine parts
This is RWO's position, set out in its own documents. It is not an IMO rule.
- Warranty. The OWS-COM manual makes the warranty conditional on several points, including using only original parts, or spare parts and chemicals approved by the manufacturer, for repairs. The same section excludes typical wear and tear parts from the guarantee, naming "all rotating parts" first [2, p. 8].
- Packing. "Only install original packing rings as a basic rule" [1, p. 5].
- Certification. RWO states that "Many RWO products are certified by flag state authorities and/or classification societies" and that "The un-authorized change of parts may not only invalidate the manufacturers’ warranty but even invalidate the certification" [4]. RWO makes this point most strongly for filter media.
How to order AEP pump parts from N&P
We supply genuine RWO AEP pump parts for OWS-COM separators to ships, managers, yards and resellers, with export packing and shipment from Singapore. Use our contact form and type these details into the "What part do you need?" field:
What to send us for a quote
- Separator model and size, e.g. OWS-COM 2.5.
- Separator serial number from the type plate, and the vessel’s IMO number. RWO asks for both.
- Pump type from the pump type plate, e.g. AEP 4-2.
- Part number(s) or item numbers exactly as shown in your RWO manual, current or old, e.g. SPSVPU318113, 5500401EP4 or “item 402”. The item number identifies the part more reliably than its name.
- Quantity of each item.
- Delivery port and required date.
Photos can’t be attached to the form. If a photo would help, mention it in your enquiry and email it to sales@npmarine.sg once we reply. If you only have an old part number, we will confirm the current one before quoting.
Request a quote for RWO AEP pump parts →FAQ
Is the stator included in the rotor package (No.3)? No. Package No.3 contains the rotor (401) with one joint bolt, two casings, a joint housing, two clamps and a collar. The stator (402) is a separate item.
Are AEP 1 and AEP 2 parts interchangeable? Partly. They share packages No.1 (SPSVPU318066), No.2 (SPSVPU318106), No.4 (SPSVPU318116) and packing PUSPCS325818. The stator and rotor package are different: PUSPCS324814 / SPSVPU318110 for AEP 1 and PUSPCS324815 / SPSVPU318111 for AEP 2.
My manual shows numbers like 5460402EP2. Are they still valid? These are the pre-2017 numbers. Use the table above, or our part number reference, to find the current number. You can also send us the old number.
References
- RWO, Appendix 1 – AEP oil-separation pump: Operating and maintenance instructions, Eccentric screw pump AEP (pump types AEP1, AEP2, AEP4-2, AEP5-2, AEP6-2), 1st edition, issued 20.07.2016. Pages used: 3–6, 8–12.
- RWO, Installation, operating and maintenance manual OWS-COM, 9th print version, 30.05.2017. Pages used: 2, 8 (warranty conditions), 9, 25, 33, 50, 53–54, 59, 60–66.
- RWO, Installation, operating and maintenance manual OWS-COM, 7th print version, 26.07.2016 (pre-2017 part numbers), pp. 60–66.
- RWO, "Original Spare Parts", https://www.rwo.de/original-spare-parts/ (accessed 7 October 2026).
Page numbers are the printed page numbers in each document.