How to Diagnose & Prevent Scale

If you’ve noticed white, chalky residue inside your hot water pressure washer, on fittings, or around your heating coil, that’s scale buildup. It’s a common issue caused by hard water minerals like calcium and magnesium, and it can quietly ruin your system’s efficiency if you don’t stay ahead of it.

What Is Scale Buildup?

Scale is a hardened layer of minerals that forms when hard water is heated inside your pressure washer. Over time, it sticks to the walls of your heating coil and other internal components. This buildup acts like insulation as it keeps your burner from heating water efficiently and puts extra strain on your system.

Why It’s a Problem

• Reduced heat transfer: Your machine works harder and burns more fuel to heat the same amount of water.

• Restricted flow: Scale can narrow coil passages and restrict water flow.

• Pump strain: The extra resistance makes your pump and unloader work harder than they should.

• Corrosion risk: Scale traps heat and moisture, which can lead to premature rusting in metal components.

How to Get Rid of Scale Buildup

The best way to remove scale is by running a descaling solution through your system, like Scale Away, which is designed to safely dissolve mineral buildup from coils, fittings, and other components.

Here’s how to descale:

1. Disconnect your detergent line.

2. Mix Scale Away according to the product instructions.

3. Circulate it through your coil (with the nozzle removed) for about 15–30 minutes.

4. Flush the system thoroughly with clean water afterward.

Important: Do not use acidic descalers like Scale Away on your unloader, pump, or aluminum components as those parts can be damaged by acidic solutions. Only descale your coil and metal fittings unless your manufacturer says otherwise.

How to Prevent It

• Use a water softener: Softened water drastically slows down mineral buildup.

• Flush your system regularly: Running clean water through the coil after each use helps prevent residue.

• Descale on a schedule: If you’re using your washer often, plan to descale every 3–6 months.

• Watch your heat: Excessively high temperatures can make scale form faster.

The Bottom Line

Scale buildup is one of the most common and preventable causes of hot water pressure washer problems. A regular descaling routine using Scale Away can keep your system performing like new, extend the life of your coil, and help you avoid costly downtime.