Brass Chemical-Resistant Pump Sprayers for Commercial HVAC | STW-2B, STW-3B
Same Viton Foundation. Built for the Jobs That Break Everything Else.
The poly Spray Towers handle residential and light commercial work all season. But if you are running acid cleaners daily, servicing rooftop equipment where gear gets dropped and kicked, or doing commercial PM routes that put 200+ cleaning cycles on a sprayer per year, you need hardware that matches the workload. The STW Brass series upgrades the core shut-off assembly to brass while keeping every Viton seal and gasket that makes the STW platform chemical-proof. The brass valve does not crack when it gets dropped off a ladder or knocked around in a service van loaded with tools.
Manufacturer’s Tech Note: The brass upgrade is primarily about durability at the main stress point: the shut-off valve. The chemical resistance of the sealing system, the 42″ hose, and the wand are identical across all STW models. If you are choosing between poly and brass based on chemical compatibility alone, both handle the full Vapco product line. Choose brass when the physical demands of the job site require it, or when you want equipment that lasts years of daily commercial use instead of a season.
What the Brass Upgrade Gets You
| COMPONENT | POLY (STW-1/2/3) | BRASS (STW-2B/3B) |
|---|---|---|
| Shut-Off Valve | Poly shut-off with Viton gaskets | Brass-plated shut-off with Viton gaskets. Impact-resistant and built for daily commercial abuse. |
| Extension Wand | 18″ Wand | 18″ Wand — Identical to poly models. |
| Hose | 42″ chemical-resistant | 42″ chemical-resistant — Identical to poly models. |
| Seals & Gaskets | Viton throughout | Viton throughout — Identical sealing system. |
| Tank | Translucent poly with funnel top | Translucent poly with funnel top — Identical tank construction. |
| Safety Lock & Check Valve | Yes | Yes — Identical safety features. |
Why Viton — and Why It Matters for Your Seals
This is not marketing language. It is materials science.
| SEAL MATERIAL | CHEMICAL RESISTANCE | FIELD LIFESPAN |
|---|---|---|
| Standard Rubber | Swells and softens on contact with concentrated alkaline or acid cleaners. | 1-3 uses before failure. |
| EPDM | Handles mild chemicals. Degrades under concentrated caustics and aromatic solvents. | Weeks to a few months depending on chemistry and frequency. |
| Viton (FKM) | Resists concentrated acids, caustics, aromatic and aliphatic solvents, and petroleum products. | Full cooling season or longer with daily rinsing after use. |
Select Your Size
Both brass models share the same upgraded hardware. The only difference is tank capacity.
| MODEL | CAPACITY | BEST FOR |
|---|---|---|
| STW-2B | 2 Gallon | Daily Commercial Service: The right balance of capacity and portability for contractors doing commercial PM work with acid or alkaline cleaners. |
| STW-3B | 3 Gallon | High-Volume Commercial & Rooftop: Maximum capacity for extended commercial runs so you spend less time mixing and more time cleaning. |
Looking for the Poly Models?
The STW-1, STW-2, and STW-3 poly models share the same Viton sealing system at a lower price point. Ideal for residential PM work and contractors who do not need the brass durability upgrade. Available in 1, 2, and 3 gallon sizes.
Compatible Vapco Coil Cleaners
Spray Towers handle the full Vapco liquid product line. – Coil Cleaning
Contractors: Please contact your local Vapco distributor for pricing and availability.
Poly vs. Brass: Quick Decision Guide
| GO POLY IF… | GO BRASS IF… |
|---|---|
| You primarily do residential PM work. | You do commercial work daily and need gear that takes a beating. |
| You run alkaline cleaners (Foaminator, Mongoose, Blue 41). | You run acid cleaners regularly and want maximum corrosion resistance. |
| You want the lowest cost of entry with full Viton protection. | You want equipment that lasts years, not seasons. |










