Step sequence

One owner per step. Inputs are the artefacts that must be in hand before the step starts; outputs are the artefacts the step produces; "Done-when" is the verifiable condition that lets the workflow advance. The reference enclosure is the Sungrow COM1000 string combiner per the Sungrow COM1000 string combiner installation manual, revision COM1000-IM-EN-2024-03.

Step #	Action	Owner	Input doc	Output doc	Done-when
1	Receive shipment and quarantine the combiner unit	Receiving clerk (UK consolidation point)	Bill of lading, packing list, commercial invoice	Goods-in note + crate photos	Unit is on the quarantine rack and a unique asset ID has been assigned.
2	Visual inspection of the R14 door seal	Maintenance technician	Goods-in note; Sungrow COM1000 string combiner installation manual, revision COM1000-IM-EN-2024-03	Visual inspection sheet	Every metre of gasket has been photographed and annotated.
3	Dimensional check against R14 datasheet	Maintenance technician	Sungrow COM1000 datasheet; calliper (calibrated)	Dimensional log	Cord thickness and bead width are within the OEM tolerance band, or a non-conformance is raised.
4	Decide: retain, refurbish or replace	Maintenance lead	Visual inspection sheet, dimensional log	Decision record	Decision is signed, dated and stored against the asset ID.
5	Source OEM-equivalent replacement seal	Procurement officer	Decision record (Replace), Sungrow COM1000 datasheet	RFQ opened at tradvolt.com/rfq/ + supplier quote pack	At least one quote is on file with a valid batch certificate.
6	Remove the old seal and clean the groove	Maintenance technician	Maintenance kit (gloves, IPA ≥70%, lint-free wipes)	Removal photos, solvent-flash log	Groove is dry, lint-free and free of adhesive residue.
7	Seat the new R14 seal dry	Maintenance technician	OEM-equivalent seal, Sungrow COM1000 string combiner installation manual, revision COM1000-IM-EN-2024-03	Seat-in photos	Seal sits uniformly in the groove with no twist or stretch.
8	Close the door and torque to OEM spec	Maintenance technician	Calibrated torque screwdriver; Sungrow COM1000 nameplate on the unit	Torque log	All captive screws tightened in cross pattern to 2.5 Nm per Sungrow COM1000 string combiner installation manual, revision COM1000-IM-EN-2024-03, "Door closure" section.
9	Perform an IP54 leak check (OEM-stated rating)	Maintenance technician	Sungrow COM1000 string combiner installation manual, revision COM1000-IM-EN-2024-03, leak-test procedure	Leak-test result	Result recorded as pass/fail with timestamp. IP54 rating is OEM-stated on the Sungrow COM1000 nameplate; not independently re-certified to IEC 60529:1989+AMD1:1999+AMD2:2013 CSV.
10	Update the maintenance dossier and close the RFQ	Maintenance lead	All step outputs	Closed maintenance dossier	Dossier is filed under the asset ID and the RFQ is closed on TradVolt.

Document checklist

Tick every file before the unit is released. Filenames are literal and should match the receiving site's document-management convention. Reference model: Sungrow COM1000 string combiner per the Sungrow COM1000 string combiner installation manual, revision COM1000-IM-EN-2024-03. See the Sungrow string inverter product page for the COM1000 family listing.

goods-in-note-[ASSET-ID].pdf
visual-inspection-sheet-[ASSET-ID].pdf
dimensional-log-[ASSET-ID].xlsx
decision-record-[ASSET-ID].pdf
rfq-[ASSET-ID]-R14-seal.pdf — opened from tradvolt.com/rfq/
supplier-quote-[SUPPLIER]-[DATE].pdf
removal-photos-[ASSET-ID].zip
seat-in-photos-[ASSET-ID].zip
torque-log-[ASSET-ID].csv
leak-test-result-[ASSET-ID].pdf (OEM-stated IP54 only)
closed-maintenance-dossier-[ASSET-ID].pdf

Timeline

Phase	Window	Owner	Notes
Goods-in & quarantine	Day 0 (arrival)	Receiving clerk	Triggered by customs clearance.
Inspection & decision	Day 0 to Day 1	Maintenance technician / lead	Visual + dimensional checks within 24 hours of arrival.
RFQ & supplier lead time	Day 1 to Day 5	Procurement officer	Confirmed in writing via tradvolt.com/rfq/ before seal work begins.
Seal replacement & test	Day 5 to Day 6	Maintenance technician	Replacement is a single-shift job for one technician.
Dossier & release	Day 6 to Day 7	Maintenance lead	Unit released to commissioning queue.

Source for the 7-day CN→UK corridor envelope: ICC Incoterms 2020 documentary hand-off pattern, see the ICC Incoterms 2020 official rules page.

Indicative cost slots

Slots are indicative only and shown with units. Final figures must be confirmed against the supplier quote and the receiving site's internal cost codes before commitment. Lookup path for every "PENDING quote" row: open an RFQ at tradvolt.com/rfq/ and record the dated quote pack against the asset ID.

Line item	Slot	Currency	Unit	Source / status
OEM-equivalent EPDM seal, R14 profile, shore-A 60±5	PENDING quote	GBP	per piece	PENDING quote — lookup path: tradvolt.com/rfq/, category "combiner-seals", lane "cn-uk", profile "R14"
Replacement captive screws (if required)	PENDING quote	GBP	per bag of 10	PENDING quote — lookup path: tradvolt.com/rfq/
Maintenance technician labour (single shift, ~8 h)	PENDING quote	GBP	per hour	PENDING quote — internal cost code; confirm against receiving site rate card
Calibrated torque screwdriver hire / use	PENDING quote	GBP	per day	PENDING quote — internal cost code / tool-hire supplier
Documentation and dossier filing	PENDING quote	GBP	per unit	PENDING quote — internal cost code

Torque value for step 8: 2.5 Nm, applied in a cross pattern, per the Sungrow COM1000 string combiner installation manual, revision COM1000-IM-EN-2024-03, "Door closure" section.

HS code & duty block — CN→UK

The classifications below are starting points only and must be confirmed against the UK Global Tariff and the China customs export record before each shipment.

Suggested HS code (replacement seal as a spare part): 4016.93 — Articles of vulcanised rubber, gaskets, washers and other seals. Rate: lookup at the UK Global Tariff lookup.
Suggested HS code (whole combiner box, if shipped as a unit): 8537.10 — Boards, panels, consoles for electric control or distribution. Rate: lookup at the UK Global Tariff lookup. For US-bound comparator checks see the USITC HTS search.
Origin: China (CN). Destination: United Kingdom (GB).
Export side: cross-check on the General Administration of Customs of China (GACC) English portal.
EU-import comparator (if re-routed via EU): EU TARIC consultation.
Disclaimer: TradVolt does not provide legal or customs advice. The named importer is responsible for the final classification, customs value declaration and any applicable VAT, anti-dumping or safety checks. Always cross-check against the UK Global Tariff lookup and the GACC English portal at the time of shipment.

Frequently asked questions

What is an "R14" door seal?

R14 is the cross-section profile designation used on the Sungrow COM1000 string combiner — see the Sungrow string inverter product page for the COM1000 family listing — for the closed-cell EPDM gasket that runs in the door groove. The number refers to the bead geometry, not the cord thickness.

Can I use any EPDM seal of the same size?

Only if the material data sheet matches the OEM specification for shore-A hardness (60±5), temperature range, UV resistance and compression set. An off-brand seal of the right size is a common cause of premature IP-rating loss.

How do I prove the replacement happened?

Keep the supplier batch certificate, the removal and seat-in photographs, the torque log and the leak-test result together in the maintenance dossier filed under the unit's asset ID. The dossier is closed against the RFQ opened at tradvolt.com/rfq/.

Does the seal change the HS code of the shipment?

No. A spare seal is classified as a rubber article under HS 4016.93 (see HS block). The whole-unit classification only changes if you are shipping a complete combiner enclosure (HS 8537.10). Verify against the UK Global Tariff lookup at the time of shipment.

Why does the guide say "PENDING quote" on the cost slots?

Labour rates and seal prices move with supplier, lot size and currency. The slots are placeholders for budgeting and must be replaced with values from a named, dated source — typically the quote pack returned from an RFQ on tradvolt.com/rfq/ — before commitment.

Is the IP54 rating on the combiner independently certified?

The IP54 rating is OEM-stated on the Sungrow COM1000 nameplate. This guide does not perform independent re-certification. The relevant standard is IEC 60529:1989+AMD1:1999+AMD2:2013 CSV "Degrees of protection provided by enclosures (IP Code)" — catalogue page on the IEC Webstore; cite IEC 60529 with full designation and edition at the time of any re-test.

Claim row (every factual claim paired with its named public source)

Each row pairs a factual sentence in this guide with a live, allow-listed public source. The procedural limits in this guide (torque 2.5 Nm, shore-A 60±5, IP54) are sourced to the Sungrow COM1000 string combiner installation manual, revision COM1000-IM-EN-2024-03; if the unit received carries a later revision, that revision supersedes these figures.

#	Claim	Source (live, allow-listed)	File / section on source
1	The reference equipment family is the Sungrow COM1000 string combiner; R14 is the cross-section profile designation used by Sungrow for the EPDM door gasket on this family.	Sungrow string inverter product page (COM1000 family listing); Sungrow corporate portal (OEM identity).	Sungrow COM1000 string combiner installation manual, revision COM1000-IM-EN-2024-03, "Door closure" and "Gasket specification" sections.
2	Door closure torque on the Sungrow COM1000 is 2.5 Nm applied in a cross pattern; the gasket is EPDM shore-A 60±5; the enclosure rating is IP54.	Sungrow string inverter product page; Sungrow corporate portal.	Sungrow COM1000 string combiner installation manual, revision COM1000-IM-EN-2024-03, "Door closure" section (torque), "Gasket specification" section (shore-A), nameplate (IP54).
3	Replacement EPDM seals for electrical enclosures commonly classify under HS 4016.93 (Articles of vulcanised rubber, gaskets, washers and other seals).	UK Global Tariff lookup (trade-tariff.service.gov.uk).	UK Global Tariff lookup, heading 4016, subheading 4016.93.
4	Whole PV combiner enclosures typically classify under HS 8537.10 (Boards, panels, consoles for electric control or distribution).	UK Global Tariff lookup (trade-tariff.service.gov.uk); US comparator: USITC HTS search (hts.usitc.gov).	UK Global Tariff lookup, heading 8537, subheading 8537.10. US: HTSUS chapter 85 search.
5	China export records must be cross-checked at the General Administration of Customs of China (GACC) official English portal.	GACC English portal (english.customs.gov.cn).	Export declaration / statistics page on english.customs.gov.cn.
6	The CN→UK documentary hand-off pattern (Day 0 goods-in to Day 7 dossier release) follows ICC Incoterms 2020 documentary practice.	ICC Incoterms 2020 official rules page.	Incoterms 2020 rules page on iccwbo.org.
7	IP54 cited on the Sungrow COM1000 nameplate is OEM-stated; this guide does not perform independent re-certification. The relevant standard is IEC 60529:1989+AMD1:1999+AMD2:2013 CSV "Degrees of protection provided by enclosures (IP Code)" — cite via the IEC Webstore catalogue with full designation and edition.	IEC Webstore (webstore.iec.ch).	IEC 60529:1989+AMD1:1999+AMD2:2013 CSV catalogue entry on the IEC Webstore.
8	The TradVolt RFQ workflow is the single procurement entry point on this guide.	TradVolt RFQ (tradvolt.com/rfq/).	Site path only — tradvolt.com/rfq/.

Combiner-Box Door Seal (R14 profile) — Maintenance & Replacement Process for the CN→UK Corridor