Your system is clean — but still inefficient

You can have a spotless plant room and still haemorrhage energy, water and uptime. Inhibitor chemicals are often dosed into closed-loop heating, chilled water and process circuits for system protection, keeping corrosion and scale at bay. But if the rest of your routine is guesswork, you end up with a “clean” system that runs like it’s dragging a caravan.

It usually shows up quietly. Pumps that sound fine but draw too many amps. Heat exchangers that pass inspection but don’t hit design duty. A weekly chemical top-up that feels reassuring, until you realise it’s compensating for a leak, oxygen ingress, or an uncontrolled bleed.

“Clean” isn’t the same as “controlled”

Most sites can point to something tangible: a clear side-stream filter bowl, a decent conductivity reading, a log that shows inhibitor added on schedule. It looks like discipline, and sometimes it is.

But control is about stability, not appearances. If your inhibitor concentration swings because of frequent top-ups, or you’re chasing pH without fixing the root cause, you’re protecting metal while wasting performance. It’s a bit like polishing the dashboard while the tyres are flat.

The hidden inefficiency pattern operators know by feel

You don’t need a catastrophic failure to be inefficient. The common pattern is a cluster of small “normal” issues that nobody owns because nothing is technically broken.

• Frequent manual dosing “to be safe”, with no trend line for residual.
• Filters that block early because the system is shedding corrosion products.
• Hot spots and cold spots that prompt setpoint tweaks instead of hydraulic fixes.
• Routine blowdown or bleed that’s set once and forgotten, regardless of load.
• Make-up water that’s higher than expected, quietly diluting treatment.

What inhibitor chemicals can’t fix on their own

Inhibitor chemicals are brilliant at what they’re designed to do: form protective films, buffer chemistry, and slow corrosion in the right operating window. They are not a substitute for a sealed, stable circuit.

If your system is breathing air, you’re feeding it oxygen. If your make-up is constant, you’re importing hardness and chlorides. If your dirt load is high, you’re turning pumps and valves into grinders. You can keep adding inhibitor and still lose the efficiency war one small deposit at a time.

Three root causes that masquerade as “needs more chemical”

1. Oxygen ingress
   Open tanks, poorly set pressurisation, or tiny suction-side leaks will keep corrosion ticking over. The water can look clean; the chemistry tells the truth.

2. Uncontrolled dilution
   Automatic fill valves that weep, unnoticed drain-downs, or frequent sampling losses can all drag inhibitor residuals down. You respond with dosing, and the cycle repeats.

3. Fouling that isn’t scale
   Magnetite sludge and biofilm don’t always show up as classic “limescale”. They still coat surfaces and steal heat transfer, which you then chase with higher flow or higher temperatures.

The calm, repeatable routine that makes “clean” efficient

The sites that run well don’t just buy the right chemistry. They build a boring, same-every-time operating habit around it-like a quiet ritual at the door after a muddy walk. It reduces firefighting, and it makes system protection measurable.

Start small. Pick a handful of checks you will do every time, in the same order, and log them so trends become visible.

• Confirm pressurisation is stable (not just “within range” today).
• Record make-up water volume weekly and set an alert level.
• Trend inhibitor residual, pH and conductivity rather than treating single readings.
• Check side-stream filtration differential pressure and clean on condition, not calendar.
• Sample from consistent points (return header beats a random drain cock every time).

The “done” definition for system protection

If you need a simple test of whether you’re truly protected, use a definition that isn’t vibes:

• Inhibitor residual stays within target band between planned service visits.
• Make-up water is low and consistent for a closed loop.
• Corrosion indicators (iron/copper trends) are flat, not creeping.
• Filters load predictably, not in sudden ugly bursts.
• Heat transfer performance meets duty without creeping setpoint increases.

When optimisation pays back faster than you expect

Efficiency losses compound. A thin layer of deposit, a slight loss of flow, a little extra pump head, a few more hours of boiler firing time-none of it triggers an alarm, but all of it shows up on energy spend and comfort complaints.

Once the circuit is stable, inhibitor chemicals start doing what they’re meant to do: maintain, not constantly recover. That’s when your chemical spend often drops, not because you’ve become reckless, but because you’ve stopped using dosing as a plaster.

A quick diagnostic you can do this week

If you’re not sure whether you’re “clean but inefficient”, run this short check and be brutally honest with the answers:

1. Do we know our weekly make-up volume? If not, start there.
   
2. Can we plot inhibitor residual over the last 8–12 weeks? If not, you’re dosing blind.
   
3. Have our setpoints crept up over the year? That’s often fouling or control drift.
   
4. Do we regularly find magnetite/sludge? Then you have a solids problem, not just a chemistry one.
   
5. Do we adjust bleed/blowdown based on measured conditions? If it’s fixed, it’s probably wrong at least half the time.

If your system is clean, that’s a win. The next step is making it predictable-because predictable systems run cheaper, fail less, and let system protection be a quiet background function rather than a weekly drama.

FAQ:

• Do inhibitor chemicals improve efficiency directly? Indirectly. They help prevent corrosion and deposits that reduce heat transfer and increase pumping energy, but they won’t fix airflow, hydraulics, control tuning or oxygen ingress.
• If the water looks clear, can we reduce dosing? Not based on appearance alone. Dose to measured residual and trend it; clarity doesn’t rule out dissolved metals, oxygen-related corrosion, or early-stage fouling.
• What’s the simplest indicator of a “leaky” closed loop? Unexpected make-up water. Track it weekly; rising or erratic make-up usually explains drifting inhibitor levels and ongoing corrosion.
• Should we increase inhibitor concentration “for safety”? Only within the supplier’s guidance. Overdosing can cause foaming, compatibility issues, or false confidence while the underlying cause (dilution/ingress) continues.
• How often should we sample? Often enough to see trends-weekly or fortnightly during stabilisation, then monthly once stable, with consistent sampling points and a clear target band.