ShopAmerex.com · Amerex 03784 datasheet · https://shopamerex.com/products/amerex-03784-downtube-assembly-125-150-lb-dry-chemical-wheeled-unit · Figures as published by Amerex · Verified Sep 2, 2026
Genuine Amerex service part·Part no. 03784
Amerex 03784 Downtube Assembly, 125/150 lb Dry Chemical Wheeled Unit
Amerex 03784 is the Downtube Assembly listed as item 7 on printed page 18 (PDF page 20) of Amerex Parts Book 27277 Rev D, in the parts list for 125/150 lb dry chemical wheeled extinguishers operated by a 23 cu. Full overview ↓
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Genuine Amerex part from an authorized Amerex distributor. Not a generic substitute.
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Which models does the Amerex 03784 fit?
Per the Amerex Parts Book · page 20| Fits | Extinguisher | UL rating | Capacity | Price | Link |
|---|---|---|---|---|---|
| Model 450 |  11483 Amerex 450 125 lb Wheeled ABC Fire ExtinguisherParts Book p.18 |
30A:240B:C | 125 lb (57 kg) | $4,960.00 | View |
| Model 452 |  10643 Amerex 452 125 lb Wheeled Purple K Fire ExtinguisherParts Book p.18 |
320B:C | 125 lb (57 kg) | $6,671.00 | View |
Parts list for 125/150 lb. dry chemical wheeled models, 23 cu. ft. nitrogen cylinder
Fitment per the Amerex Parts Book. Check the part number against your unit’s nameplate before ordering.
What is the Amerex 03784?
Amerex 03784 is the Downtube Assembly listed as item 7 on printed page 18 (PDF page 20) of Amerex Parts Book 27277 Rev D, in the parts list for 125/150 lb dry chemical wheeled extinguishers operated by a 23 cu. ft. nitrogen cylinder — models 450 (125 lb ABC) and 452 (125 lb Purple K). It is specific to that family: the 300/350 lb wheeled models on the next parts list use downtube assembly 17235 instead. Amerex service manual 05605 governs annual maintenance on these units and includes a siphon tube clearing and gas tube integrity check. Amerex states that its replacement parts must be used to protect the UL listing and keep the warranty in effect, and that substitute parts void both the Amerex extinguisher warranty and the UL listing.
Amerex 03784 specifications
| Part number | 03784 |
|---|---|
| Description | Downtube Assembly |
| Parts Book page | Printed page 18 (PDF page 20) |
| Diagram item | 7 |
| Pack quantity | 1 (sold individually) |
| Models | 450, 452 |
|---|
| Amerex item number | 03784 |
|---|
Part data as published by Amerex. Confirm against the current Parts Book revision before ordering for a unit in service.
Amerex 03784 documents
Official Amerex publications · PDFCurrent Amerex publications, hosted on ShopAmerex so links do not break when Amerex reorganizes its site.
Other parts on Parts Book page 20
Parts list for 125/150 lb. dry chemical wheeled models, 23 cu. ft. nitrogen cylinder · All 11 parts| Part no. | Part | Pack | Price | Quantity and add to cart |
|---|---|---|---|---|
| 03785 | 1 (sold individually) | $151.00 | ||
| 03787-P001 | Pack of 1 | $200.00 | ||
| 03817 | Each | $1,188.00 | ||
| 03818 | 1 (sold individually) | $156.00 | ||
| 04072 | 1 (sold individually) | $30.99 | ||
| 06467 | 1 (sold individually) | $191.00 | ||
| 11970 | Each | $6.99 | ||
| 13956 | 1 (sold individually) | $4.99 |
Item numbers refer to the exploded view on the Parts Book page. Model-specific items are marked in the Amerex parts list; confirm before ordering.
Amerex 03784 questions
What does the Amerex 03784 downtube assembly fit?
Amerex 125/150 lb nitrogen cylinder wheeled dry chemical models 450 (125 lb ABC) and 452 (125 lb Purple K), per the parts list on printed page 18 of Parts Book 27277 Rev D.
Where is part 03784 in the Amerex Parts Book?
Item 7 on printed page 18 (PDF page 20).
Will the 03784 fit the 300 lb wheeled models 491 and 493?
No. The Parts Book lists 17235 as the downtube assembly for the 300/350 lb wheeled models on printed page 19.
Is the Amerex 03784 a genuine Amerex part?
Yes. Amerex's Parts Book notice states that Amerex replacement parts must be used to protect the UL listing and keep the warranty in effect, and that the warranty is voided by generic, off-the-shelf or substitute parts.
Does a 450 or 452 have to be depressurized before this part is serviced?
Yes. Manual 05605 warns that a check valve prevents nitrogen from escaping the agent cylinder when the nitrogen hose is disconnected, so the agent cylinder may still be pressurized, and all pressure must escape before further disassembly.
How often does Amerex require maintenance on these wheeled units?
At least once a year, or more often if circumstances require, in accordance with NFPA 10.
Does the Amerex 03784 ship charged or pressurized?
No. It is an uncharged mechanical service part, unlike the charged 03817 nitrogen cylinder on the same parts list.