Quick answer
In short
For an equipment manufacturer, a custom coil is a purchased component: a stainless or copper coil, finned core, tube assembly or header built to the OEM's drawing and fitted into the OEM's own product. What matters most is drawing and revision control, interface dimensions, materials, the inspection and test plan, packing and labelling, and how a first batch is approved before repeat orders. Uniinox coordinates drawing-based coils, finned cores, tube fabrication and assemblies through one export contact; the inspection and documentation scope is agreed in each quotation.
Components OEMs buy as custom parts
Most OEM coil purchases fall into one of the product families below. Each product page lists the inputs needed for that family.
| Component | Typical role in the equipment | Product page |
|---|---|---|
| Stainless helical and immersion coils | Heating or cooling a liquid in a tank, vessel or compact unit | Stainless steel heat exchanger coils |
| Copper tube coils | Formed copper heat-transfer tubing inside equipment | Custom copper tube coils |
| Finned cores, condensers and evaporators | Air-side heating, cooling or heat rejection | HVAC coils and finned cores |
| Tube fabrication | Bent tubes, return bends and connection preparation | Copper tube fabrication |
| Integrated and OEM assemblies | Coils combined with headers, frames, casings or vessel interfaces | Custom OEM heat exchanger assemblies |
Related: Stainless steel heat exchanger coils, Custom copper tube coils, HVAC coils and finned cores, Copper tube fabrication, Custom OEM heat exchanger assemblies
Control the drawing and its revision
Send the drawing with its revision letter and mark the dimensions that control the fit: connection positions, overall envelope and mounting points. Give tolerances for those dimensions and say which features are only for reference.
Name the material grade and, where it matters, the standard it must meet, for example ASTM A269 for austenitic stainless tubing. Conformity to a standard applies only where it is agreed for the order. State which changes need your approval before production, such as a material substitution or a different joint method.
Approve a first batch before repeat orders
Before the first production order, agree how the first parts will be checked: which dimensions are measured, which pressure or leak test is applied and at what value, and which records are returned with the shipment. Uniinox agrees inspection points and release documents with the buyer before production, so the same plan can be repeated on later batches.
Related: Quality and inspection approach
Packing, labelling and repeat supply
State how the parts must arrive: protection for connection ends, cleanliness requirements, labels with your part number and revision, pack quantity and the packing method. Uniinox prepares shipments to the packing scope agreed in the order.
Share the expected annual quantity and typical batch size. They affect tooling, material planning and how parts are packed for each delivery.
What to send for a quotation
The list below is the minimum for a first technical review. Photos, sketches or a size list help if you do not have a complete drawing yet.
- Drawing with revision, controlled dimensions and tolerances
- Material grade and any standard the material must meet
- Working media, operating temperatures and pressures
- Inspection and test plan for the first batch and for repeat orders
- Packing, labelling and cleanliness requirements
- Annual quantity, batch size and delivery schedule
Frequently asked questions
Questions about this application
Can Uniinox build to our existing drawing?
Yes. Uniinox works from the buyer's drawing or project requirements. Catalog configurations are references only; the approved drawing controls production.
Which inspection documents can be supplied?
The scope is agreed for each order. List the dimensional reports, pressure or leak test records and material documents you need in the enquiry; their availability is confirmed in the quotation.
What is needed to quote a repeat OEM part?
The current drawing revision, the material, the inspection and packing requirements, the annual quantity and the typical batch size.
Can several components be supplied as one assembly?
Yes. Uniinox coordinates coils, headers, frames, casings and vessel interfaces as one drawing-based assembly. Identify every interface and which parts your team will supply.
Primary sources
Technical references
These references support the general points above. They do not certify a Uniinox product or replace the approved project design.
- ASTM A269/A269M-25: Seamless and Welded Austenitic Stainless Steel Tubing for General ServiceASTM International
A widely used tubing specification to name when an enquiry calls for austenitic stainless tube to a recognised standard; conformity applies only where agreed for the project.
- Heat Exchangers, Chapter 47ASHRAE Handbook—HVAC Systems and Equipment, 2024
General heat-exchanger selection inputs, materials, fouling, pressure, temperature and maintenance considerations.