**Short answer:** VAT ties spare parts to the valve's **fabrication number** (on the label). Its manuals say to quote that number when ordering, because the ordering number alone doesn't pin down seal material or variant. In the Series 650 DN 320–400 manual, the "Seal kit vacuum (Viton)" (206528 / 230884 / 244437 for DN320 / DN350 / DN400) contains only the **body seal and the gate seal**. The bonnet seal, the actuator feedthrough seals and the 24 sealing-ring shaft-feedthrough seals are separate line items. Read the spare-parts table line by line before you RFQ "a seal kit".
This post breaks down two public VAT Installation, Operating & Maintenance (IOM) manuals:
- **Series 650, DN 320–400 (I.D. 12–16")**, pendulum control & isolation valve with stepper drive actuator. Document 230985EI, dated 2010-09-27, served as a PDF from the Kurt J. Lesker website.
- **Series 655, DN 250 (I.D. 10")**, pendulum control & isolation valve with DeviceNet interface. Document 979645EA, Edition 23.09.2019, 112 pages, on vatgroup.com.
Where to find the manual for your valve
1. Read the label first. The 655 manual says "The fabrication number and order number are fixed on the product directly or by means of an identification plate". The 650 manual tells you to use "the yellow label on valve".
2. Search VAT's download area or a distributor's library for the **series + DN**, then check the manual's cover. Each manual starts with "This manual is valid for the valve ordering number(s): …". Don't use a manual unless your ordering-number pattern is on that list.
3. Note the document number and edition (e.g. 979645EA / 23.09.2019). Different editions can have different spare-parts tables.
Reading the ordering number
| Manual | Ordering-number pattern on cover | Position that varies | Meaning (as printed) |
|---|---|---|---|
| 650 DN320–400 | `65050 - P. 52 - . . . .` / `65050 - J. 52 - …` / `65050 - T. 52 - …` | letter after first dash | P = ISO-F flange, J = JIS flange, T = ASA-LP flange (the cover lists DN350 / 65051 with the JIS flange only) |
| 650 DN320–400 | `65050` / `65051` / `65052` | 5-digit base | DN320 / DN350 / DN400 |
| 655 DN250 | `65548 - . .GQ`, `. .AQ`, `. .HQ`, `. .CQ` | interface code | G: 2 sensor inputs / analog outputs; A: + ±15 V sensor power supply; H: + power failure option; C: + both |
| 655 DN250 | `655 . . - . A . .` / `. H . .` / `. I . .` | body/plate finish | A = aluminium, H = aluminium hard anodized, I = aluminium nickel coated |
Why the finish letter matters: the 655 manual gives different leak rates by finish. Leak rate to outside at 20 °C is 1 × 10E-9 mbar l/s for aluminium and nickel-coated but 1 × 10E-5 mbar l/s for hard anodized. Valve seat leak rate is 1 × 10E-9 vs 1 × 10E-4 mbar l/s. Two valves that look alike can carry different finishes and different spare plates.
**Don't generalise the positions across series.** The two manuals use the letter positions differently: the 650 cover uses a flange letter, the 655 cover an interface code. This post covers only these two documents.
The spare-parts table, Series 650 DN320–400
| Item | Description | DN320 | DN350 | DN400 |
|---|---|---|---|---|
| 1 | Bonnet seal, Viton | N-5100-280 | N-5100-281 | N-5100-282 |
| 2 | Body seal (Viton), includes 2 ml vacuum grease syringe | 206529 | 230885 | 244435 |
| 3 | Gate seal, Viton | N-5100-279 | N-5100-280 | N-5100-282 |
| — | **Seal kit vacuum (Viton) = items 2 + 3** | **206528** | **230884** | **244437** |
| — | Vacuum grease syringe 2 ml / 5 ml | 206792 / 206793 | ||
| 4 | Actuator feedthrough seals (Viton), 2 pcs per valve | N-5111-329 | ||
| 5 | Sealing-ring shaft-feedthrough seals (Viton), 24 pcs per valve | N-7121-112 | ||
| — | ISO-F centering ring with Viton O-ring (aluminium) | 32050-QAZV | – | 32052-QAZV |
Traps in this table:
- **The same N-number shows up in two roles.** N-5100-280 is the DN320 *bonnet* seal and also the DN350 *gate* seal. N-5100-282 is both bonnet and gate seal on DN400. The number identifies a seal, not a position. If you order "2 × N-5100-282" for a DN400 you may be covering both positions, so check the quantity per valve.
- **The "seal kit" is not everything.** Items 1, 4 and 5 are separate. A full reseal of a DN320 means the kit (206528) plus the bonnet seal plus the feedthrough seals if they are due.
- **Materials other than Viton are "on request".** The manual says seal materials "are declared on dimensional drawing of specific valve ordering number". If your tool runs a non-Viton seal (e.g. an FFKM upgrade), the kit numbers above do not apply.
Series 655 DN250: what's customer-replaceable
| Item | Description | Part number |
|---|---|---|
| 3 | Bonnet seal | N-5100-278 Viton (other on request) |
| 10 | Gate seal | N-5100-275 Viton (other on request) |
| 13a / 13b | Rotary feedthrough seals (vacuum lip seal / vacuum–atmosphere) | N-5100-226 Viton |
| — | Vacuum grease syringe | 206792 (2 ml) / 206793 (5 ml) |
| — | O-ring removal tool | 234859 |
| — | Centering ring with Viton O-ring, ISO-F | 32048-QAZV (aluminium), 32048-QEZV (stainless) |
The 655 manual adds: "VAT makes a difference between spare parts that may be replaced by the customer and those that need to be replaced by the VAT service staff." The table lists only the customer-replaceable ones. Items such as the disk, gate complete and flange seals show "-" (no number published).
Maintenance intervals, and a contradiction inside one manual
| Manual | Isolation seals | Actuator / feedthrough seals |
|---|---|---|
| 650 DN320–400 | 200,000 cycles unheated; 6 months heated ≤ 80 °C; 3 months heated > 80 °C | 1 million cycles; 6 months; 3 months |
| 655 DN250, chapter 7.1 | 75,000 cycles but 12 months unheated; 6 months but max. 75,000 cycles heated ≤ 80 °C; 3 months but max. 75,000 cycles heated > 80 °C | 2,000,000 cycles; 6 months; 3 months |
| 655 DN250, product description table | "Cycles until first service: isolation cycles 200'000 (unheated and under clean conditions)" | throttling cycles 1,000,000 |
The 655 manual gives **200,000** isolation cycles "until first service" in its technical data, and a **75,000-cycle / 12-month** seal-replacement recommendation in its maintenance chapter. For PM planning and spares stocking, the maintenance-chapter figure is the conservative one. Both manuals add that the figures are for clean conditions and that the process can shorten them. Both also flag grease life at temperature ("grease will separate to PTFE and oil").
Equivalents: evidence levels
| Claim | Evidence level |
|---|---|
| Kit 206528 = body seal 206529 + gate seal N-5100-279 for DN320 Series 650 | **Documented by maker** (650 manual) |
| A third-party O-ring of the same dimensions replaces an N-5100 seal | **Interchangeability not established.** VAT publishes no dimensions for N-5100 parts in these manuals and states "Use only spare parts manufactured by VAT" |
| Seal numbers in the 650 manual apply to 655 or other series | **Not established.** The tables differ |
What to send in an RFQ
1. Photo of the valve label: **fabrication number** and ordering number.
2. Series, DN, flange type, body finish.
3. Which positions: bonnet, gate/plate, body, actuator/rotary feedthrough. Quantity per valve.
4. Current seal material (Viton or other) and process temperature.
5. Genuine VAT only, or open to alternatives for a qualification trial.
6. Manual document number and edition you are working from.
FAQ
**Is the VAT seal kit the full reseal?** Not in the 650 DN320–400 manual. The kit covers body seal + gate seal only.
**Can I order spares with just the ordering number?** Both manuals ask for the fabrication number to make sure the right parts are supplied.
**Why two different service intervals in the 655 manual?** The description table gives cycles until first service. The maintenance chapter gives a more conservative replacement recommendation. Plan PM on the maintenance chapter and on your own process data.
*VAT is a trademark of VAT Group AG. Viton® is a trademark of its owner. Names and part numbers are used for identification only. MST is not affiliated with or endorsed by VAT.*
Original OEM documents (links only)
1. VAT Vakuumventile AG, "Installation, Operating & Maintenance Instructions – Series 650, DN 320-400 (I.D. 12-16") Pendulum Control & Isolation Valve with stepper drive actuator", doc. 230985EI, 2010-09-27, 19 pp. (VAT document; copy hosted by distributor Kurt J. Lesker): https://www.lesker.com/newweb/valves/vat/files/230985.pdf
2. VAT, "Installation, Operating & Maintenance Instructions – Pendulum control & isolation valve with DeviceNet® interface, Series 655, DN 250 mm (I.D. 10")", doc. 979645EA, Edition 23.09.2019, 112 pp. https://www.vatgroup.com/uploads/downloads/file/655_HV_Pendulum_Control_Valve_65548_PACQ_CHO1_Manual-979645ea.pdf
Request a quote
Need a VAT seal, seal kit or spare located or quoted? Include a photo of the valve label with the fabrication number. Post a [find-part request](/community/new?kind=part_request&mpn=65548) with the details above, or send a [sourcing RFQ](/services/sourcing-rfq?sourcing_mode=supplier_match). MST replies in the thread or by email. MST does not claim stock of any item mentioned here; sourcing is done on request.
Piezas