Set an Amerex B402 beside a B500 and you would be forgiven for ordering one hose for both. Both are 5 lb ABC dry chemical on the anodized aluminum valve, 15.25 in. tall and 4.25 in. deep, at 195 PSIG nominal, emptying in 14 seconds with a 12 to 18 ft. range.
Their hose and horn assemblies are different part numbers, and one will not do for the other. The B402 takes 14849-P. The B500 takes 06215-P. The published difference between them is ten thousandths — .157 against .147.
The number in parentheses
Open Amerex's Parts Book to any hose and horn page and you'll find a decimal printed after the models each assembly serves — "14849-P Hose & Horn Assembly - B402 (.157)", "06215-P Hose & Horn Assembly - B453, B500 (.147)", "05564-P Hose & Horn Assembly - B456 (.191)".
Amerex prints the figure without a legend. It is not the hose diameter, because Amerex states diameter separately: it sizes the hose strap by it — 15747-P is the "Strap & Clip Asy (Black Plastic - 3/8” Hose)", 14778-P the 1/2 in. version — and it spells out bore and length outright on wheeled hoses, as in "06015 Hose Assembly 1/2 in. X 25 ft. with Gasket". The same parenthetical convention carries over to wheeled nozzle tips, where Amerex prints "06208 Nozzle Tip - 495 (.328)" for a machined tip with no hose attached at all. We call it the orifice on our product pages. Whatever you call it, it is frequently the only published difference between two assemblies that share hose diameter and valve family.
The Parts Book is unambiguous about what that precision is worth: "Amerex parts have machined surfaces and threads which are manufactured to exacting tolerances. O-rings, hoses, nozzles, horns and all metal parts meet precise specifications and are subjected to multiple in-house inspections and tests for acceptability. The Amerex warranty is voided by the use of generic, off-the-shelf or substitute parts. DO NOT SUBSTITUTE."
And on the same page: "To protect the UL listing and to keep the warranty in effect Amerex replacement parts must be used."
Where Amerex publishes a discharge rate next to the discharge time, the figure's effect is easy to read. The high-flow line is built, in Amerex's words, "for applications where discharge rates exceeding one pound per second are required as specified in NFPA 10," at "twice the flow rate of standard models." The 720 at 10 lb ABC uses a .312 assembly and discharges at 1.22 lb./sec. in 10 seconds. The 722, the same 10 lb in Purple K, uses a .250: 1.15 lb./sec. in 12 seconds. The 20 lb pair lines up the same way: 760 at .266, 1.14 lb./sec.; 762 at .228, 1.08 lb./sec.
Amerex says these units "utilize the same hardware and are manufactured to the same UL specifications as Amerex compliance-rated products." Set the 720 beside the B441: same 10 lb ABC, same brass valve, both listed at 20.5 x 8.75 x 5 in. and 195 PSIG. The B441 empties in 22 seconds, the 720 in 10 — on 06095-P at .152 against 20914 at .312.
Capacity doesn't pick the assembly. The listing does.
This is where wrong orders start. The B402 and B500 hold the same 5 lb of the same agent, but Amerex lists the B402 at 3A:40B:C and the B500 at 2A:10B:C. Two UL listings, two part numbers. (More in Amerex B402 vs B500.)
It holds in the other direction. Assembly 05248 at .152 serves the B479, a 5 lb Purple K rated 30B:C over 12 seconds, and the B443, a 6 lb ABC rated 3A:40B:C over 14.5. Different agent, capacity and rating, one part number. Agent and weight alone will not tell you what you need.
Valve family is the other half of the answer
Two 10 lb ABC extinguishers, both rated 4A:80B:C, both 22-second discharge, both 15–21 ft. range: the B456 on the anodized aluminum valve, the B441 on chrome-plated brass. The B456 takes 05564-P at .191, the B441 06095-P at .152.
The same split repeats at 20 lb ABC, both rated 10A:120B:C over 30 seconds: the aluminum-valve A411 at .209, the brass-valve 423 at .174. Same published ratings and discharge times, different valve family, different part number — which is why "20 lb ABC" is never enough to order from. Unsure which valve you're holding? Our aluminum vs. brass valve parts guide walks the visual differences.
It decides the sealing part too. Amerex labels its hose gaskets by valve, not model: 01532-P is the "Hose/Nozzle Gasket (O-Ring) - Aluminum Valve," 06978-P the "Hose Gasket (O-Ring) - Brass Valve."
Hose and horn assemblies by model
Part numbers and figures below are from the Parts Book; ratings and discharge times from Amerex's current catalog.
| Model | Agent / capacity | Valve | Hose & horn P/N | Figure | UL & ULC rating | Discharge |
|---|---|---|---|---|---|---|
| B402 / B402T | ABC 5 lb | Aluminum | 14849-P | .157 | 3A:40B:C | 14 sec |
| B500 / B500T | ABC 5 lb | Aluminum | 06215-P | .147 | 2A:10B:C | 14 sec |
| B479 / B479T | Purple K 5 lb | Aluminum | 05248 | .152 | 30B:C | 12 sec |
| B443 | ABC 6 lb | Aluminum | 05248 | .152 | 3A:40B:C | 14.5 sec |
| B456 | ABC 10 lb | Aluminum | 05564-P | .191 | 4A:80B:C | 22 sec |
| A411 | ABC 20 lb | Aluminum | 11221-P | .209 | 10A:120B:C | 30 sec |
| A413 | Purple K 20 lb | Aluminum | 11223 | .177 | 120B:C | 28 sec |
| B424 | ABC 5 lb | Brass | 03753 | .140 | 2A:10B:C | 14 sec |
| B461 | ABC 6 lb | Brass | 03753 | .140 | 3A:40B:C | 14 sec |
| B441 | ABC 10 lb | Brass | 06095-P | .152 | 4A:80B:C | 22 sec |
| B460 | Purple K 10 lb | Brass | 06095-P | .152 | 80B:C | 22 sec |
| 423 | ABC 20 lb | Brass | 03339-P | .174 | 10A:120B:C | 30 sec |
| 415 | Purple K 20 lb | Brass | 05174 | .177 | 120B:C | 28 sec |
The Parts Book also lists 06215-P against the B453. At 30 lb the brass line continues: 12603-P at .216 for the 692 ABC, 13439 at .191 for the 693 Purple K. High Performance and Z-Series models carry their own ten-assembly table, from 14794 at .149 for the 599 and 716 to 14789-P at .312, which alone serves the 567, 569, 584, 792, 795 and 796.
ULC variants are separate part numbers
This catches anyone servicing a mixed fleet. Amerex's dry chemical extinguishers conform to CAN/ULC-S504 – UL 299 and CAN/ULC-S508 – UL 711, and the ULC models it lists with an X suffix take their own assemblies: 06541 at .166 for the ULC B456X, against .191 for the B456; 11658 at .221 for the ULC A441X; 01304 at .157 for the ULC B441X. Our model number decoding guide covers the suffixes that change what fits.
CO2: no figure in parentheses, but a continuity test
Carbon dioxide assemblies carry no decimal, and Amerex's catalog splits the CO2 line on a row it labels DESIGN. The 322 at 5 lb is a Tube & Horn unit: a discharge tube plus the 01772-P horn, with the diffuser, per the CO2 manual, "built into the discharge tube." The 330, 331 and 332 are Hose & Horn units, taking 01782 on the 330 and 01705-P on the 331 and 332.
Two things follow. First, the horn is a separate part — 00572-P for the 330, 00593 for the 331 and 332 — so the failure Amerex describes, replacing the horn "if brittle, cracked or deformed," doesn't require a whole hose.
Second, a CO2 hose is an electrical part. Amerex: "Carbon dioxide hose assemblies have a continuous metal braid that connects to both couplings to minimize static shock. A hose continuity test shall be performed using a basic conductivity tester consisting of a flashlight having an open circuit and a set of two wires with a conductor (clamps or probe) at each end (NFPA 10)." Amerex lists that as its own step, separate from the visual inspection before it.
On wheeled units, the tip does the metering
Wheeled hoses are plain lengths: 1/2 in. x 25 ft. on the 50 lb 495 and 497 units, 3/4 in. x 50 ft. across the 125/150 lb units, 1 in. x 50 ft. on the 125/250 lb High Performance and Z-Series. The metered dimension moves to a separate nozzle tip, printed in the same parenthetical form: 06208 at .328 for the 495 and the 490, 06470 at .344 for the 488 and 476, 09399 at .625 for the 573 and 756, and 08260 at .531 for the 575, 690, 758 and 759. The 497 takes its own tip, 06210.
A damaged wheeled hose is a length-and-diameter problem, a wrong tip a flow problem, and the two are ordered separately. Check the gasket on the same parts list — the 50 lb unit calls out 07247-P at the hose and 03877-P at the nozzle, while the 125 lb and larger lists carry a single 03877-P "Gasket, Hose and Nozzle." On reassembly Amerex's wheeled manuals are specific: "WHEN ASSEMBLING THE HOSE TO THE AGENT CYLINDER OR NOZZLE TO THE HOSE, TIGHTEN THE COUPLING ¼ TURN AFTER CONTACTING THE HOSE GASKET." More on platform differences in our wheeled unit parts guide.
Before you replace the whole assembly
Amerex's dry chemical maintenance procedure asks the technician to "visually inspect threads on nozzle or hose coupling, horn and hose for damage," then to "blow air through nozzle or hose and horn to insure passage is clear of foreign material." Plenty are serviceable once cleared.
What wears out is often smaller: the gasket, and the strap and clip holding the hose to the cylinder. Amerex sizes those by hose diameter and cylinder size rather than by model — 15747-P for 3/8 in. hose on 4¼ and 5 in. cylinders, 14778-P for 1/2 in. hose on 7 in. cylinders, 14871-P for 1/2 in. hose on 8 in. cylinders.
What we stock
Aluminum valve assemblies — 14849-P (.157), 06215-P (.147), 05248 (.152), 05564-P (.191), 11221-P (.209) and 11223 (.177).
Brass valve assemblies — 03753 (.140), 06095-P (.152), 03339-P (.174), 05174 (.177) and 12603-P (.216).
CO2, clean agent and specialty — the 01782 and 01705-P CO2 assemblies with replacement horns, the 14436 (.247) Halotron I assembly for the 397, the 10744 Class D hose with quick connect, and the 27476-P for C260 and C262 wet chemical. The full range sits in Hoses, Nozzles & Horns and Wheeled Unit Parts, within our service parts catalog.
Working from a nameplate photo or a list of models across a site? Send it over and we'll come back with exact part numbers, availability and lead time — request a quote.
Sources
Part numbers, the figures in parentheses, model fitment and gasket and strap sizing are from the Amerex Corporation Portable & Wheeled Parts Book (Part No. 27277 Rev C). Ratings, capacities, dimensions, discharge times and rates, ranges and valve types are from Amerex's current portable fire extinguisher catalog, which states these extinguishers conform to CAN/ULC-S504 – UL 299 and CAN/ULC-S508 – UL 711 (CO2: CAN/ULC-S503 – UL 154 and CAN/ULC-S508 – UL 711). Service language is quoted from Amerex's owner's service manuals for stored pressure hand portable dry chemical (P/N 05602) and carbon dioxide portable extinguishers (P/N 05603) and its wheeled dry chemical manuals (P/N 05612, P/N 27085). Amerex revises part numbers between printings, so confirm any assembly against the extinguisher's nameplate and Amerex's current documentation before ordering, and have inspection, maintenance and recharge performed by a qualified fire equipment service company per NFPA 10 and your authority having jurisdiction.
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