Description
The 1616747281 is the OFS I-41, the Stage 2 element of the oil-free screw range, documented across the ZR 160, ZR 200, ZR 250 and ZR 275 frames, the ZT 160, ZT 200, ZT 250, ZT 275 and ZT 315 frames, and the ZR 315 VSD. Its record reaches back through the supersession chain 9825066081, 1616679281 and 1616747281, a line Atlas Copco itself published when the Stage 2 long Mk II design entered service.
At 118.80 kg and a 60 × 44 × 37 cm envelope, this is the second-stage renewal that a standard workshop gantry handles without special arrangements, and the figures are published so the lift can be planned before the order is placed.
This article sets out what the I-41 designation covers, how the supersession chain reads, which machines the parts lists name, and where the documented range ends.
Identity of the 1616747281 Element
An element is the core compression stage of a screw compressor, and in the oil-free machines the compression train is split into two stages in series. The 1616747281 fills the Stage 2 position: it takes the partly compressed air from the first stage and raises it to the final discharge pressure.
Because the second stage works at the highest pressure in the machine, its rotors and bearings carry the heaviest load in the train, and its condition decides the discharge temperature and the delivered flow of the whole unit. That is why the 1616747281 is confirmed against a compressor record rather than against a description.
What the OFS I-41 Designation Covers
OFS is the oil-free screw designation, and I-41 is the element code Atlas Copco records for this stage. The parts lists print it as SERVICE STAGE O.F.S. I-41, and the item record carries the short form OFS I-41; both name the same unit.
Atlas Copco prints the number in two forms. The ten-digit form 1616747281 is what the item record carries, and 1616 7472 81 is the printed form used across the parts documents. The nameplate of the element carries the printed form, so a fitter reading the old unit and a planner quoting the item record always land on the same stage.
The Supersession Chain from 9825066081
The 1616747281 did not appear as a fresh number; it continues a line Atlas Copco documented publicly. The historical service news from December 2001 announced the Stage 2 long Mk II design for the ZR/T 160-275 frames and the ZR 315 VSD, and it recorded the old Stage 2 element 9825 0660 81 as superseded by 1616 6792 81.
The chain therefore reads 9825066081, then 1616679281, then 1616747281, and the current number is the one the present parts lists carry. The evolution matters in practice because machines documented under the older numbers draw from the same Stage 2 position, and the parts records tie the three references together.
A supersession chain is confirmed reference by reference, not assumed from the model family: the service news covers the first step, and the current parts lists cover the last one, which is what lets Seadweer quote the 1616747281 against machines whose files still carry either older number.
Machines Documented for the 1616747281
Atlas Copco’s official parts lists and equipment records name the I-41 stage across the ZR and ZT ranges in three groups, collected in the table below and taken in turn afterwards.
| Group | Documented units |
| ZR series, 160-275 platform | ZR 160, ZR 200, ZR 250, ZR 275 |
| ZR series VSD | ZR 315 VSD |
| ZT series | ZT 160, ZT 200, ZT 250, ZT 275, ZT 315 |
The ZR 160-275 Records
The parts list for the ZR/ZT 160-275 platform carries a Compressor element 2 section, and it lists 1616 7472 81 as the O.f.s. stage at ref. 1030. That single listing covers the platform, and the individual frames inside it are documented further: the ZR 275 record names the stage directly as SERVICE STAGE O.F.S. I-41, and equipment records for the ZR 160 and ZR 250 in service quote the same element number against specific machines.
The ZR 200 sits inside the same continuous 160-275 platform, with the ZR 160, ZR 250 and ZR 275 documented on either side of it, so the platform record carries the frame as well. For a plant running several of these frame sizes, one Stage 2 reference across the group simplifies the spares position: one identification, held once, covering the whole set.
The ZR 315 VSD Record
The VSD documentation has its own element section for the ZR 315 VSD, and it lists the 1616747281 as the OFS I-41 alongside the service stage 1616 5904 91. That listing reaches back to the same 2001 service news, which named the ZR 315 VSD inside the Stage 2 long Mk II application range from the start.
The variable-speed drive changes how the machine modulates, and the Stage 2 element underneath stays the I-41 position of the platform, confirmed from its own parts list rather than inferred from the fixed-speed records.
The ZT Series Records
The ZT frames share the platform with their ZR counterparts, and the same 160-275 parts list records 1616 7472 81 as the O.f.s. stage for the ZT 160, ZT 200, ZT 250 and ZT 275. The ZT 315 is documented through its own parts information, which names the I-41 number for the machine.
That spread means an oil-free site running ZR and ZT frames side by side draws one Stage 2 element reference for the whole fleet, and the identification work happens once instead of per machine.
The I-41 and I-42 Stages
The parts information for the large frames names a sibling stage beside the I-41: 1616747282, the OFS I-42. The two numbers sit in the same product family but they are different elements, and the machine record decides which one a given unit takes.
That is also why the 1616747281 is confirmed against the element number being renewed or the machine parts list, never against the family name alone: the I-41 and the I-42 look alike on the outside and answer to different numbers.
Where the Documented Range Ends
The documented coverage stops where the parts lists stop naming the I-41. The ZR 315 in its non-VSD builds and the ZT 315 VSD have no parts list in hand naming the 1616747281, so they stay outside the confirmed range until a machine record says otherwise, and coverage follows the parts list for each serial number.
That is also why the range is not widened to other oil-free frames: the platform documentation names the I-41 where it applies, and the check against the machine nameplate and the old element number is what keeps the right stage matched to the right frame.
What the Oil-Free Screw Stage Does
Oil-free compression runs on a condition the I-41 is built around: no oil enters the compression chamber, so the air that leaves the 1616747281 carries no injection oil to separate out downstream.
Dry Compression in the Second Stage
The rotor pair turns in a precision-bored housing with the clearances sealed by tight machining tolerances and by timing gears keeping the rotors from touching. Because no oil film does the sealing, the stage depends on its bearings, its seals and its cooling circuit, and the air path stays clean from inlet to discharge.
Precision rolling bearings take the radial and thrust loads of the shafts, and the cooling between the stages brings the air temperature down before the 1616747281 raises it to the final pressure. Everything about the air quality after the machine — the dryers, the filters, the point of use — is sized around the oil-free condition this stage preserves.
Renewed as One Assembly
The 1616747281 is renewed as a complete unit rather than rebuilt in place. The rotor pair, the housing and the bearings arrive as one factory assembly with the ports and the drive interface set for the machines it serves.
That is what makes the renewal a planned swap instead of a workshop project: the old stage comes out, the new one goes in on its mounting faces, and the machine returns to its log with a fresh serial to record.
Handling the 118.8 kg Stage
At 118.80 kg and 60 × 44 × 37 cm, the 1616747281 sits in the two-person-plus-gear class: above manual carrying, well within the reach of a workshop gantry or an engine crane rated for the mass. The figures describe the unit as it is supplied, and they shape the route from the unloading point to the machine.
Lifting and Access
The 60 × 44 × 37 cm envelope reaches the site packed, and the openings it has to pass are measured in advance: doorway widths, gantry height and the standing room in front of the machine. A gantry or crane rated for the 118.80 kg of the 1616747281 covers the lift, and the slinging keeps the load level through the move.
The stage is carried on its mounting faces and never on its shaft. Port caps stay in place until the moment of fitment, so nothing reaches the bore while the unit is exposed.
Setting Down and the First Run
Before the machine is closed up, the mounting faces are cleaned and checked for burrs, the coupling is inspected for wear, and alignment and direction of rotation are confirmed. Once running, the machine is brought up unloaded and watched while the readings settle.
Discharge temperature, pressure and vibration are logged through the first running period, and fasteners are re-torqued after the first hours. That short log becomes the baseline for every later check on the 1616747281.
Wear Signs and Renewal Timing
Renewal of the 1616747281 is decided on condition rather than on a fixed hour count. Two lines of evidence carry most of that decision, and both read best as trends taken at a fixed interval rather than as single figures.
Readings That Track Wear
The rotor surfaces and the bearings are what change first. As they wear, the running clearances open and the stage delivers less air at the same shaft power, so a falling free air delivery measured at the rated pressure is the reading that follows that change. Discharge temperature at a steady load moves with it.
Three further readings carry the same story:
- More power drawn for each unit of air delivered at a steady load, which separates a worn 1616747281 from a machine whose demand has changed.
- Vibration at the bearing housings, read at a fixed interval so the level forms a trend rather than a single figure.
- Rising discharge temperature between the stages, which moves with the internal condition of the second stage and shows up in the intercooler readings first.
Planning the Renewal
Left unchecked, bearing wear can end with the rotors contacting, and at that point the stage is written off rather than renewed. A planned renewal avoids that outcome, because the unit is changed while the frame, the drive and the pipework are still in good order.
The serial recorded in the machine file is what makes that timing judgement easier, since it ties the readings to a known stage rather than to a model in general.
Ordering the 1616747281 Through Seadweer
Two pieces of information lock the order down: the number on the element being renewed — whether it reads 1616747281, 1616679281 or the older 9825066081 — and the model and serial number from the compressor nameplate.
What to Send
Send both to Seadweer and the parts desk checks the number against the machine record and confirms the 1616747281 in one pass. Where the number on the old element has worn away, the nameplate is enough on its own, because the parts list for the machine names the element it was built with.
Plants that run several ZR and ZT machines keep a short record for each unit: model, serial number and element number. That record turns the next enquiry into a single message with a confirmed answer, and it is the same record the parts desk works from when the 1616747281 is quoted.
What the Quotation Confirms
The quotation repeats the item data of the 1616747281: the OFS I-41 designation, the packed size, the weight, the country of origin and the tariff code. One confirmation covers the whole renewal, so the workshop plans the lift and the stop without a second enquiry for the same stage.
Send the machine details with the enquiry and the answer comes back with the fitment already checked. That is the whole of the ordering process for a 1616747281 renewal.
Technical Specifications
The tables below collect the identification data and the physical figures recorded for the 1616747281.
Part Identification
| Item number | 1616747281 |
| Designation | OFS I-41 |
| Printed form | 1616 7472 81 |
| Previous numbers | 1616679281 (1616 6792 81); 9825066081 (9825 0660 81) |
| Stage | Stage 2, oil-free rotary screw |
| Core platform | ZR/ZT 160-275 and ZR 315 VSD |
Dimensions and Weight
| Dimensions (L × W × H) | 60 × 44 × 37 cm |
| Weight | 118.80 kg |
| Country of origin | Belgium |
| Customs tariff code | 8414900090 |
The 118.80 kg weight and the 60 × 44 × 37 cm envelope describe the 1616747281 as it is supplied, and they set the handling plan for the fitting day. Seadweer confirms the current package details with the quotation.
FAQ
What is the 1616747281?
The 1616747281 is the OFS I-41, the Stage 2 oil-free screw element documented for the ZR 160, ZR 200, ZR 250 and ZR 275, the ZT 160, ZT 200, ZT 250, ZT 275 and ZT 315, and the ZR 315 VSD. It is a complete factory assembly renewed as a unit rather than rebuilt in place.
What is the difference between 1616747281, 1616679281 and 9825066081?
They are three references on one supersession chain. The service news from 2001 replaced 9825066081 with 1616679281 when the Stage 2 long Mk II design entered service, and the current parts lists carry 1616747281. Machines documented under the older numbers draw from the same Stage 2 position.
Which compressors take the 1616747281?
The documented coverage is the ZR 160-275 platform including the ZR 200, the ZR 315 VSD, and the ZT 160, ZT 200, ZT 250, ZT 275 and ZT 315. Fitment for a specific machine is confirmed from its serial number record.
Is the 1616747281 the same as the OFS I-42?
No. 1616747282 is the OFS I-42, a sibling stage in the same product family. The I-41 and the I-42 are different elements, and the machine record decides which one a given unit takes.
How heavy is the 1616747281?
The item data lists 118.80 kg in a 60 × 44 × 37 cm envelope, so the lift is planned with a gantry or crane rated for that mass. The 1616747281 is carried on its mounting faces and never on its shaft.
How do I order a renewal for my compressor?
Read the number on the element being renewed and note the model and serial number from the compressor nameplate. Send both to Seadweer and the fitment is confirmed against the parts list for that machine before the order is placed.
More Parts List
Should you need other Atlas Copco air compressor parts, the table below lists further models. Take a look, or contact us and we will follow up.
| Part Number | Part Name | Part-Number |
|---|---|---|
| 1616747282 | O.F.S. I-42 | 1616-7472-82 |
| 1616747283 | OFS I-02 GAS | 1616-7472-83 |
| 1616747287 | O.F.S. I-47 | 1616-7472-87 |
| 1616747263 | OFSI-26 | 1616-7472-63 |
| 1616753592 | SERVICE ELEMENT C55 F09 | 1616-7535-92 |
| 1606331883 | COOLER | 1606-3318-83 |
| 1089059021 | SOLENOID VALVE | 1089-0590-21 |
| 0291112811 | NUT | 0291-1128-11 |
| 1901622736 | PUHSBUTTON BLACK ATEX | 1901-6227-36 |
| 1901016116 | O-ring | 1901-0161-16 |
| 2204029018 | Heater Element-D12*1830 36 380 | 2204-0290-18 |
| 6996012626 | HOSE, FLANGE, 2+, 1389MM | 6996-0126-26 |
| 2200633322 | ANELLO OR 6275 | 2200-6333-22 |
| 1623837900 | PIPE | 1623-8379-00 |
| 1504221542 | VALVE SOLENOID | 1504-2215-42 |
| 1625001743 | GEARSET 05/06 | 1625-0017-43 |
| 1650111136 | ZH450 55 PSI 60HZ PIN1 XS | 1650-1111-36 |
| 6259026400 | KIT REPAR.VPM INTEGR.7,5/20 | 6259-0264-00 |
| 1092191192 | CAPSCREW KIT | 1092-1911-92 |
| 1622287800 | DRIVE SHAFT | 1622-2878-00 |
| 1650112643 | ZH450 9 BAR ST2 LINER | 1650-1126-43 |
| 2202717400 | GASKET | 2202-7174-00 |
| 1631018517 | AXIAL FAN 700/3-3/S4ZR/40 | 1631-0185-17 |
| 1091032280 | VALVE | 1091-0322-80 |
| 9095369100 | HOSE PIPE | 9095-3691-00 |
| 2906008100 | KIT-SERVICE | 2906-0081-00 |
| 1637911632 | FITTING PIPE THREADED STRAIGHT | 1637-9116-32 |
| 2914809300 | FILTER ELEMENT | 2914-8093-00 |
| 2205178456 | HOSE (C146) | 2205-1784-56 |
| 1621801800 | BEAM | 1621-8018-00 |
| 1621639300 | PIPE | 1621-6393-00 |
| 6996012379 | MAINTENANCE KIT | 6996-0123-79 |
| 2200902441 | A1 (C40) AC 115/60UL SPARE | 2200-9024-41 |
| 1624625129 | AIR BALL VALVE V-358T DA 1/2+ | 1624-6251-29 |
| 1624824682 | VALVE ASSEMBLY DN150 | 1624-8246-82 |
| 1305500021 | CRANKSHAFT | 1305-5000-21 |
| 1900291076 | MOUNTING PLATE | 1900-2910-76 |
| 1092901163 | ANTI-VIBRATION SUPPORT | 1092-9011-63 |
| 2202822380 | PIPE ASSY DRYERS A16-A17 | 2202-8223-80 |
| 1637964425 | HOSE ASSEMBLY | 1637-9644-25 |
| 2230011217 | GA200/315 HD NEW OVERHAUL KIT | 2230-0112-17 |
| 2236102013 | CAP, AFTERCOOLER, T3 | 2236-1020-13 |
| 2200599841 | KIT VALV.TERMOST.CSD75-125 | 2200-5998-41 |
| 1901903805 | KIT FLEXIBLE HN | 1901-9038-05 |
| 1631016900 | SUPPORT FAN WING 560 CUBICLE | 1631-0169-00 |
| 2000022599 | MOTOR WIRING | 2000-0225-99 |
| 2204125856 | DECAL MODEL DRB 34 IVR | 2204-1258-56 |
| 2906908100 | KIT, GEARBOX INSPECTION | 2906-9081-00 |
| 1089948265 | DRIVE | 1089-9482-65 |
| 1310030120 | ARRESTOR-SPARK | 1310-0301-20 |
Declan Moorehaven –
Our ZR 275 and a customer’s ZT 250 both came due for a second-stage renewal in the same quarter, and the old files quoted two different numbers for what looked like the same stage. Seadweer traced both to the OFS I-41 through the supersession chain and explained why the neighbouring frames stay on their own stages. The element landed at 118.8 kg, light enough that our existing gantry covered it without a special booking. Straight answers from the first message.