Attribute Schema Library
Attribute schemaHVACR

Refrigerant Line Set Attributes

A refrigerant line set is a matched pair of ASTM B280 ACR copper tubes — an insulated suction (vapor) line and a smaller liquid line — coiled to a fixed length and sold as one SKU. Buyers are HVAC contractors matching a condenser to an air handler or a ductless head, and the counter and e-commerce staff who serve them.

Two things make the data hard. Sizing convention: ACR copper is designated by actual OD; plumbing copper (Type L, ASTM B88) is designated nominal, an eighth under. Both arrive in the same column. And the word "wall": a line set has two — copper and insulation — and feeds routinely publish one Wall Thickness field without saying which. Manufacturer item pages often list the insulation wall and omit the copper wall entirely.

Then variant explosion. Liquid OD × suction OD × length × insulation wall × flared/plain × jacket yields hundreds of near-identical SKUs whose differentiator lives in a part-number suffix, not a field. A2L adds one more: R-454B and R-32 are named on the nameplate; R-410A-era catalogs have no refrigerant field to match.

Core

Every SKU needs these. Without them the record is not a product, it is a row.

Liquid Line OD
enum · in
3/8 in OD

The smaller, usually uninsulated line. Half of the size pair a buyer matches to the equipment. First facet on every line set rail.

Suction (Vapor) Line OD
enum · in
3/4 in OD

The larger insulated line. Set by the equipment's rated capacity and line length; wrong OD is discovered on the roof, not at the counter.

Overall Length
number · ft
50 ft

Coil length as shipped. Buyers order to the measured run plus slack; long-line applications change the size pair entirely.

Line Set Type
enum
Mini-split (ductless)

Mini-split and standard split sets share ODs but differ on ends, insulation and kit contents. Separates two distinct buying rails.

Insulation Wall Thickness
enum · in
1/2 in

Drives code compliance for the run. Unconditioned and outdoor runs need thicker wall than a short conditioned-space run.

Insulation Material
enum
Elastomeric closed-cell (EPDM), black

Elastomeric closed-cell and polyethylene behave differently on UV, temperature and flame spread. Determines where the set can legally run.

End Connection Type
enum
Flared both ends

Flared vs plain end decides whether the tech brazes or lands a flare nut. Lives in an MPN suffix on most feeds instead of a field.

Copper Alloy
enum
C12200 (DHP copper)

ASTM B280 permits C10200, C12000 or C12200. Line sets are near-universally C12200 DHP; spec'd jobs still call the alloy out.

Manufacturer Part Number
identifier
40620500B3B6C

The number the counter actually searches. Carries end type and jacket in its suffix, so it must be stored verbatim, not cleaned.

GTIN / UPC
identifier
685768376569

Required for marketplace listings and scan-based receiving. Absent GTIN blocks syndication regardless of how good the specs are.

Differentiating

What buyers actually compare on. This is where catalogs win or lose the filter.

Copper Tube Wall Thickness
number · in
0.032 in

Determines the rated working pressure. The single most-omitted spec in the category, and the one that separates ACR from substituted Type L.

Rated Working Pressure
number · psi
700 psi (1/2 in OD x 0.032 in wall, C12200)

Printed on the tube and the carton, rarely in the record. The proof point for R-410A and A2L high-pressure work.

Refrigerant Compatibility
text
R-410A, R-454B, R-32

A2L equipment names its refrigerant on the nameplate. Without this field a buyer cannot filter a set to the job they are quoting.

Jacket Type / UV Resistance
enum
UV-resistant polymeric jacket, black

Exposed outdoor runs without a line hide need a UV-stable jacket. The premium SKU's whole reason to exist, usually stranded in the product name.

Kit Contents
text
Line set + 14/4 stranded comm cable + 5/8 in drain hose + flare nuts

Mini-split sets ship as kits. Whether the comm cable, flare nuts and drain hose are in the box changes the comparison and the price.

Compliance & identifiers

Standards, regulatory data, and the identifiers channels reject you for missing.

ASTM B280 Conformance
boolean
true (dehydrated, nitrogen-charged, capped both ends)

B280 requires the tube be dehydrated and capped or plugged both ends. That cleanliness pedigree is what keeps debris out of the compressor.

Insulation Surface Burning Rating
enum
25/50 per ASTM E84

Plenum and ceiling-space runs require flame spread <=25 and smoke developed <=50 per ASTM E84. Inspector-facing, and inspectors do check.

Country of Origin
enum
United States

Domestic-content job specs and federal work turn on it. Also drives duty treatment on copper tube imports.

The fields that aren't in the schema at all

What most refrigerant line sets catalogs are missing.

The table above is the schema most catalogs already have. These are the attributes that usually aren't in it — each one surfaced by a signal from the live market rather than by an audit of what's already there. This is what Anglera's Schema Foundry does on a real catalog, in this category.

Supplier signal
+ Copper Tube Wall Thickness

Mueller's own item pages and Johnstone's spec table for the same SKU both publish an insulation wall and no copper wall. On most line set listings, 'wall thickness' silently resolves to the foam.

Buyer can't confirm the tube meets the pressure on the equipment nameplate, so the RFQ goes to whoever publishes the number. Substituted Type L is also invisible.

Search signal
+ Refrigerant Compatibility

Buyers search 'R-454B line set' and land on R-410A-era records with no refrigerant field. The only hits come from marketing copy, not a filterable attribute.

A2L jobs get spec'd from the nameplate. With no refrigerant field the set can't be matched or filtered, and the contractor buys the line set with the equipment instead.

Supplier signal
+ Rated Working Pressure

Manufacturers print the rating on the tube and the carton (700 psi for 1/2 in OD x 0.032 in wall C12200); distributor spec tables rarely carry it as a field at all.

No filter for high-pressure work, and spec'd or inspected jobs can't verify the set from the record — a phone call to the counter over a low-value line item.

Supplier signal
+ Insulation Surface Burning Rating

Insulation makers publish ASTM E84 25/50 data down to the product sheet; the distributor line set record describes the same insulation only as 'black foam' or '1/2 in wall'.

Plenum and ceiling-space runs fail inspection. A 50 ft set that has been uncoiled and cut comes back as a return the distributor eats.

Competitor signal
+ Jacket Type / UV Resistance

UV SKUs carry the property in the product name ('Duraguard UV') and nowhere else. A search for 'UV resistant line set' returns free-text matches, not a facet.

The premium UV SKU can't be merchandised against the commodity one, so it loses on price; outdoor runs get the wrong jacket and the insulation chalks.

How Schema Foundry finds these

Messy in, governed out.

The same value, spelled every way HVACR suppliers spell it. A filter only works once they agree.

Suction (Vapor) Line OD
3/43/4".7503/4 in OD19.05 mm0.75
0.750 in OD

ACR is designated by actual OD. A bare 3/4 read as nominal Type L resolves to 7/8 in OD — a different tube and a different fitting.

Insulation Wall Thickness
1/2".51/2 in wall12.7 mm13mmHalf inch
0.500 in

Suppliers also send copper wall as 'wall'. The two must land in separate columns or the pressure rating and the code check both break.

End Connection Type
FlaredFlarePre-flaredPlain EndNon-FlaredB3B6
Flared - both ends

Mueller encodes ends in an MPN suffix (...B3B6). Feeds ship the suffix and no field, so flared and plain sets collapse into one listing.

Line Set Type
Mini SplitMini-SplitMiniSplitDuctlessCentral SplitStandard
Mini-split

Mini-split and standard sets share ODs but differ on ends, insulation and kit contents. One governed value keeps the two rails apart.

What buyers ask

Every one of these should be answerable from the attributes above. If it isn't, that's a gap.

  • Will a 3/8 x 3/4 set work with my 3-ton R-454B condenser?
  • Is that 3/4 the actual OD, or nominal like plumbing copper?
  • Does it come pre-flared, or am I flaring 50 feet on the roof?
  • What's the copper wall? Is it rated for 410A/454B pressures?
  • Is 1/2 in insulation enough to run through an unconditioned attic?
  • Can this run outside without a line hide, or does it need a UV jacket?
  • Does the 50 ft kit include the 14/4 comm cable and the drain hose?
  • Is the copper US-made? The job spec calls for domestic.

What channels require

The same SKU, different mandatory fields per destination.

Distributor e-commerce site and counter search
Liquid Line ODSuction (Vapor) Line ODOverall LengthInsulation Wall ThicknessEnd Connection TypeRefrigerant Compatibility
Amazon Business
GTIN / UPCBrandManufacturer Part NumberLine Set TypeOverall LengthCountry of Origin
Grainger / MRO marketplace
Liquid Line ODSuction (Vapor) Line ODOverall LengthManufacturer Part NumberBrandCountry of Origin
HARDI-member supplier data exchange (PDX) feeds
Manufacturer Part NumberGTIN / UPCBrandCountry of OriginOverall Length

Refrigerant Line Sets data, in practice

On a line set, does 'wall thickness' mean the copper or the insulation?

Both, depending on the supplier — which is the problem. Manufacturer item pages for line sets commonly publish an insulation wall (1/2 in, 1 in) and no copper wall at all, and distributor spec tables inherit that single field. They are not interchangeable. The copper wall — typically around 0.030–0.035 in for common line set sizes — determines the rated working pressure. The insulation wall determines code compliance for the run. Carry them as two separate attributes, Copper Tube Wall Thickness and Insulation Wall Thickness, and never let a feed collapse them into one column called 'Wall'.

Why doesn't a 3/8 in ACR line set match 3/8 in Type L copper?

ACR tube (ASTM B280) is designated by actual outside diameter. Plumbing copper (ASTM B88, Types K/L/M) is designated by nominal size, which runs an eighth of an inch under the actual OD — nominal 3/8 in Type L is 1/2 in OD. So a 3/8 in ACR tube and a 3/8 in Type L tube are physically different, and flare or braze fittings sized for one will not land on the other. B280 also requires the tube be dehydrated and capped, plugged or crimped at both ends; B88 does not, so Type L arrives with no cleanliness pedigree for a sealed refrigerant circuit. If a feed sends a bare '3/8' with no convention stated, it is ambiguous. Normalize to actual OD and say so.

Do line set records need new fields for R-454B and other A2L refrigerants?

At minimum, a refrigerant compatibility field and a published rated working pressure. A2L equipment names its refrigerant on the appliance nameplate, and the installation instructions call for components matched to it. Catalogs built for R-410A generally have neither field, so a buyer searching 'R-454B line set' either gets nothing or gets a keyword hit from marketing copy. The copper is often the same C12200 ACR tube either way — but the buyer still has to prove the match, and the record is what proves it. Pressure rating matters for the same reason: it is marked on the tube and the carton, and it is usually absent from the data.

How many line set SKUs does a full catalog carry, and why does that matter?

Multiply the axes: liquid line OD (1/4, 5/16, 3/8), suction line OD (3/8, 1/2, 5/8, 3/4, 7/8), length (15, 25, 30, 35, 50, 100 ft), insulation wall (3/8, 1/2, 1 in), ends (flared, plain), jacket (standard, UV). Only valid pairings ship, but the result is still several hundred near-identical records. Manufacturers encode the difference in part-number suffixes — Mueller's flared sets carry a B3B6-style suffix — so the distinguishing spec often exists only inside the MPN string. If nobody parses it into fields, the filter rail cannot separate the SKUs and the counter has to do it by phone.

More HVACR schemas

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