Inhibitor protects a heating system from the inside. It slows the corrosion that turns metal into sludge, which blocks radiators, reduces efficiency and shortens boiler life. But inhibitor levels drop over time through leaks, top-ups with fresh water and system work.
That's why checking the level matters, not just adding inhibitor at installation. The Express Inhibitor Test gives a simple pass or fail on the spot, so you know the system is protected and can prove it.
The Express Inhibitor Test is a pot of 50 test strips, one strip per system. Each pot has a colour chart on its pot
The strips measure molybdate, the active ingredient in most inhibitors. That means the test works with all Fernox Protectors, including Protector F1, and with any other molybdate-based inhibitor.
Chemical Fields | Express Inhibitor Test |
Turbidity | ✕ |
Corrosion | ✕ |
pH | ✕ |
Molybdate (mg/L) | ✓ |
A fail means the system doesn't hold enough inhibitor. You can fix it on the same visit: dose the system with more inhibitor, let it circulate, then retest and issue a passing report. There's no need to come back another day.
Testing inhibitor concentration helps you comply with BS 7593:2019, the UK code of practice for treating water in heating systems, and the Benchmark scheme. Many boiler manufacturers also need proof of correct water treatment to keep the warranty valid, and the PDF report provides it.
