Attribute Schema Library
Attribute schemaplumbing & PVF

Water Heater Attributes for Plumbing & PVF Distributors

A water heater is three products in one record: a pressure vessel, a fuel-burning or electrical appliance, and a plumbing fixture in potable-water contact. Buyers are replacement plumbers who need it on the truck today, mechanical contractors sizing new construction, and facility MRO buyers.

The data is hard because the variants don't differ by size. A 50-gallon gas tank fans out into dozens of SKUs separated only by venting type, NOx class, anode, and warranty term — compliance flags, not dimensions. Input arrives as BTU/h from one supplier, MBH from the next, MBTU from a third, kW from the electric line.

Worse, the decisive numbers are conditional and catalogs strip the condition. Recovery is at a stated rise, tankless GPM is quoted at 35°F, 45°F and 67°F rise, and UEF only compares inside its draw-pattern bin. Jacket diameter, vent connection size, and required air volume usually live in the installation manual PDF, not the spec table.

Core

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

Fuel Type
enum
Natural Gas

Gas and electric SKUs are not interchangeable, and NG and LP units differ by orifice and manifold pressure. A merged facet ships the wrong burner.

Heater Configuration
enum
Storage Tank

Storage, tankless, and heat pump hybrid are different install jobs, different venting, and different sizing math. First filter a buyer touches.

Nominal Storage Capacity
number · gal
50 gal

Primary sizing facet and the trigger for federal efficiency tiers — above 55 gal, electric goes heat pump and gas goes condensing under NAECA.

Rated Input
number · BTU/h
40,000 BTU/h (40 MBH)

Drives recovery, gas line and meter sizing, and which listing applies: 75,000 BTU/h is the split between Z21.10.1/CSA 4.1 and Z21.10.3/CSA 4.3.

Element Wattage / Voltage / Phase
text
4,500 W @ 208/240 VAC, 1-phase, non-simultaneous

Electric SKUs are chosen off the panel. 208 vs 240, 1-phase vs 3-phase, and simultaneous vs non-simultaneous elements change recovery and breaker size.

Tank Profile & Jacket Dimensions
text · in
Tall — 20-1/2 in dia x 61-1/4 in H

Replacement work is a fit problem first. Lowboy and Short are not synonyms — a lowboy trades height for diameter and may not clear the closet door.

Working Pressure
number · psi
150 psi

150 psi is the residential norm; ASME-rated commercial tanks run 160 psi. Sets the T&P relief valve and matches the spec the engineer wrote.

Manufacturer Part Number (MPN)
identifier
PROG50-40N RH67 PV

The only key that survives the manufacturer price file, the rep's quote, and the contractor's PO. Suffixes encode the vent and NOx variant.

GTIN-14 / UPC
identifier
671632800094

Required by every syndication target and by branch barcode scanning. A missing GTIN blocks the record before any spec is read.

Differentiating

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

Venting Type & Vent Connection Size
text · in
Power Direct Vent, 3 in

Atmospheric, power vent, direct vent and power direct vent each need different vent material and clearances — and power vent needs a 120V outlet.

Recovery Rate @ 90°F Rise
number · GPH
40.6 GPH @ 90°F rise

How commercial buyers size. Meaningless without the stated rise — a figure at 100°F rise and one at 90°F rise are not the same number.

First Hour Rating
number · gal
81 gal

Tank volume plus recovery in the first hour — the number that answers 'how many showers'. Also sets the UEF draw pattern for storage units.

Rated Flow @ Temperature Rise
text · GPM @ °F rise
8.7 GPM @ 45°F rise

Tankless output collapses as rise climbs. A unit rated 11.2 GPM at 35°F rise gives 5.6 GPM at 67°F — the number that matters in a cold-inlet market.

Uniform Energy Factor (UEF)
number
0.64

The DOE metric since 2017 and the basis of utility rebates. Comparable only against units tested in the same draw-pattern bin.

Warranty Term (Tank / Parts)
text
6-year tank / 6-year parts

Water heaters are merchandised on warranty. The 6, 9 and 12-year SKUs are often the same tank with a different anode and element. Buyers filter on it.

Compliance & identifiers

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

NOx Emission Class
enum
Ultra Low NOx — 14 ng/J (20 ppm)

Low NOx is 40 ng/J; Ultra Low NOx is 14 ng/J (20 ppm) per SCAQMD Rule 1146.2 and the districts that follow it. Wrong class fails inspection.

Agency Certification / Listing
text
CSA/ANSI Z21.10.1 - CSA 4.1; NSF/ANSI 372

Fuel and input decide the listing: Z21.10.1/CSA 4.1 at or under 75,000 BTU/h, Z21.10.3/CSA 4.3 above it, UL 174, UL 1453, ASME Section IV HLW.

Country of Origin
enum
United States

Required for customs entry, marketplace listings, and Buy American / federal project specs. Also drives tariff exposure at the branch.

The fields that aren't in the schema at all

What most water heaters 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
+ UEF Draw Pattern (Usage Bin)

Spec sheets print UEF next to its draw pattern because UEF only compares within a bin. Catalogs keep the number and drop the bin, so an efficiency sort ranks a point-of-use unit above an 80-gallon.

Efficiency sorts rank incomparable products against each other, and rebate submissions bounce when the utility form asks for a bin the catalog never captured.

Supplier signal
+ Rated Flow at Stated Temperature Rise

Manufacturers publish tankless GPM at 35°F, 45°F and 67°F rise. Catalogs carry one 'Max GPM'. The Navien NPE-240A2 is 11.2 GPM at 35°F rise and 5.6 GPM at 67°F — same unit, same page.

A unit sized off the headline GPM under-delivers in a cold-inlet market. Callback, uninstall, return freight, and the contractor sizes the next one at a competitor.

Competitor signal
+ NOx Emission Class

Competitor filter rails expose Low NOx and Ultra Low NOx as separate facets; most distributor catalogs leave 'Low NOx' inside the marketing description, where it cannot be filtered or validated.

A 40 ng/J unit shipped into a 14 ng/J district fails inspection after install. Uninstall, return freight, and a contractor who now buys water heaters somewhere else.

Search signal
+ Anode Rod Type

Buyers on softened or high-sulfate water search 'aluminum anode' or 'powered anode' to avoid rotten-egg odor and get zero results. Same-family SKUs often differ only by anode and warranty term.

A magnesium anode in softened water produces sulfide odor. The complaint arrives as a warranty claim on a tank that is not defective, and the branch eats the swap.

Supplier signal
+ Required Air Volume & Ambient Range (HPWH)

Manufacturers state a minimum air volume and an ambient range — Navien's NWP500 runs 41–113°F — in the installation manual, not the spec table catalogs scrape. No field exists to hold it.

A heat pump unit sold into a small closet never reaches rated UEF and falls back to resistance elements. The customer blames the product; the rebate is denied.

How Schema Foundry finds these

Messy in, governed out.

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

Fuel Type
Nat GasNGN/GNaturalGas - NaturalNAT
Natural Gas

NG and LP units differ by orifice and manifold pressure. If 'Gas' collapses both, the facet puts a propane unit on a natural gas line.

Rated Input
40 MBH40 MBTU40,000 BTU40000 Btu/hr40K BTU11.7 kW
40000 BTU/h

MBH means thousand BTU/h; suppliers use MBTU for both thousand and million. Mixed in one column, numeric sort and range filters break.

NOx Emission Class
Ultra Low NOxUltra-Low NOxULNUL NOxUltra Low Nox14 ng/J
Ultra Low NOx (14 ng/J)

Ultra Low NOx (14 ng/J) is a different product from Low NOx (40 ng/J). Collapsing the two puts uninstallable units in SCAQMD carts.

Venting Type
AtmosphericNat DraftNatural DraftStd VentStandard VentAtmos
Atmospheric (Natural Draft)

One supplier's 'Standard Vent' is another's 'Atmospheric'. Six spellings across three lines make the vent facet unusable on the filter rail.

What buyers ask

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

  • Will a 50-gallon fit in a 24-inch closet, and is the vent on top or the side?
  • What's the real GPM at a 45-degree rise? My inlet is 50°F in January.
  • Is this Ultra Low NOx or just Low NOx? I'm in South Coast.
  • Can I drop this on the existing atmospheric vent, or do I need new pipe and an outlet?
  • How many showers back to back — what's the first hour rating?
  • Is that 208 or 240, single or three phase, and what breaker does it need?
  • Is the anode magnesium? The house is on a softener and the last tank stunk.
  • What's actually different between the 6-year and the 9-year version of this tank?

What channels require

The same SKU, different mandatory fields per destination.

ASA Product Data Standard (PDS)
Manufacturer Part Number (MPN)GTIN-14 / UPCFuel TypeNominal Storage CapacityTank Profile & Jacket DimensionsAgency Certification / Listing
Distributor site (Ferguson, Winsupply, Hajoca)
Fuel TypeNominal Storage CapacityVenting Type & Vent Connection SizeFirst Hour RatingWarranty Term (Tank / Parts)NOx Emission Class
MRO marketplace (Grainger, MSC, Zoro)
Rated InputElement Wattage / Voltage / PhaseWorking PressureAgency Certification / ListingCountry of OriginGTIN-14 / UPC
Amazon Business
GTIN-14 / UPCManufacturer Part Number (MPN)Country of OriginTank Profile & Jacket DimensionsNominal Storage CapacityUniform Energy Factor (UEF)

Water Heaters data, in practice

Why does UEF need a draw pattern stored next to it?

UEF replaced Energy Factor as the DOE metric in 2017. The test assigns each unit to one of four draw patterns — Very Small, Low, Medium, High — based on first hour rating for storage units or maximum GPM for tankless, then runs between 9 and 14 draws at varying volumes and flow rates. A Very Small-bin point-of-use heater and a High-bin 80-gallon are tested against different loads, so their UEF numbers are not comparable. Store the bin as its own governed field and scope every efficiency sort and rebate export to it. A UEF number with no bin is a number your filter rail cannot honestly use.

Low NOx or Ultra Low NOx — how should the catalog model this?

As a governed enum, not a phrase in the description. SCAQMD Rule 1146.2 sets 14 ng/J (20 ppmv, corrected to 3% stack O2, dry) for Type 2 units, and other districts have adopted the same or similar limits; ordinary Low NOx is 40 ng/J. They are different products with different burners, and 'Low NOx' in a title covers both. Once NOx class is a field, you can bind it to ship-to ZIP and stop the order before it becomes an uninstall. Left in free text, no rule can read it.

How should tankless GPM be stored?

Never as a single 'Max GPM'. Manufacturers publish flow at several rises because output falls as rise climbs: the Navien NPE-240A2 is 11.2 GPM at 35°F rise, 8.7 GPM at 45°F, and 5.6 GPM at 67°F. The headline number is always the smallest rise. Store GPM as a value paired with its rise, or carry discrete fields per published rise, and let the buyer filter on the rise their groundwater actually demands. The same logic applies to storage recovery: a GPH figure is only meaningful with the rise it was measured at — 90°F rise is the common convention, and 100°F rise appears on commercial sheets.

Which listings and standards actually apply to a water heater?

It depends on fuel and input. Gas storage at or below 75,000 BTU/h falls under CSA/ANSI Z21.10.1 / CSA 4.1; above 75,000 BTU/h, plus circulating and instantaneous units, falls under Z21.10.3 / CSA 4.3. Household electric storage tanks are listed to UL 174; electric booster and commercial storage tank heaters to UL 1453. ASME-rated tanks are built to ASME Section IV Part HLW and typically carry 160 psi working pressure against the usual 150 psi. Potable-water contact brings NSF/ANSI 61 into the plumbing codes, with NSF/ANSI 372 as the lead-content method behind it. Store the listing as a repeatable field — most SKUs carry several.

More plumbing & PVF schemas

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