Industrial Water Treatment · Ohio

Closed-Loop System Treatment.

Corrosion protection and pH control for heating and chilled-water loops, including mixed-metallurgy systems.

Chemical Engineer-Led · Since 1998
Industrial & Commercial clients across Ohio
AP Tech · Advantage Controls partners
American-Owned & Operated · Urbana, Ohio
Hoffman Water-branded closed-loop control panel with Walchem controller and metering pumps

Closed Loops Corrode From the Inside

Closed loops are easy to ignore. They run sealed, the makeup volume is small, and nothing seems to be happening, until corrosion products break loose and clog coils, control valves, and heat exchangers.

Every gallon of makeup brings fresh oxygen and hardness into the loop. Without the right inhibitor and pH, that adds up to corrosion from the inside, even when the makeup volume is small. We build closed-loop programs around the metals in your system and check them on a regular schedule.

“Added pH adjust to a mixed-metallurgy closed loop system today.” Doug Hoffman, Hoffman Water

What a Closed-Loop Program Covers

One program for hot and chilled systems, matched to the metals in your loop and the way it runs.

Corrosion Inhibitor Selection

The right inhibitor depends on the metals in the loop. We select and dose nitrite, molybdate, or another chemistry to fit your system.

Deposition & Scale Control

Even sealed, a loop can drop scale and deposits from hardness in the makeup. We add deposition and scale control to the program so coils and heat exchangers stay clean.

pH Adjustment for Mixed Metallurgy

Copper, steel, and aluminum each have a different safe pH range. We adjust pH to protect the most sensitive metal in the loop.

Glycol & Freeze Protection

Concentration checks, inhibitor levels, and fluid replacement before degraded glycol turns acidic and starts attacking metal.

Loop Cleaning & New-System Prep

Cleaning, pre-treatment, and start-up of new or fouled loops, so the inhibitor protects clean metal instead of sitting on top of debris.

Inhibitor & Contaminant Testing

Regular testing for inhibitor level, pH, and contaminants, so you catch a problem before it reaches a coil.

Ongoing Monitoring

Scheduled service to keep inhibitor and pH in range as the loop ages and makeup comes and goes.

Closed-loop feed panel with a Walchem controller, solid feeders, and metering pumps installed by Hoffman Water

Clean Installs, Quiet Loops

A closed-loop treatment install kept clean and serviceable by the Hoffman Water team.

Closed-loop install by Hoffman Water.

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Not sure what's happening inside your loop?

We'll test the loop, check inhibitor and pH, and tell you what it needs.

Closed-Loop Questions

Most closed loops only need quarterly testing, but it depends on the system. Loops with frequent makeup, recent repairs, or a history of corrosion get checked more often. The point of testing is to catch a dropping inhibitor level or a pH swing before corrosion products start plugging coils and valves.
Mixed metallurgy is the main reason closed loops need a real program instead of a one-time dose. Aluminum in particular narrows the safe pH range, so the inhibitor and pH have to be chosen for the most sensitive metal in the loop. We test for it and adjust pH to protect every metal in the system, not just the steel.
Yes. Glycol adds its own requirements: the freeze point has to be verified, and glycol breaks down over time into acids that attack metal. We test glycol concentration and inhibitor levels together and top up or replace the fluid before it turns corrosive.

Protect the loop before it clogs.

Request a site assessment and we'll build a closed-loop program around your system.

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