Postal Tests & Parameters

The five tests at a glance

Water Quality Test (16 parameters). A paperless, smartphone-driven postal test that checks the key indicators of system water quality. It covers appearance, pH, conductivity, alkalinity, hardness, the main corrosion metals (iron, copper, aluminium) and inhibitor markers. It's the lightest domestic test and suits routine checks.

Diagnostic Water Test (43 parameters). The most thorough domestic test. It covers everything in the System Health Check plus calcium, magnesium, nitrite, sulphates and glycol levels (monoethylene and monopropylene). It also runs the most complete mains water analysis, with 17 parameters. That makes it the choice for complex faults and for systems containing antifreeze, such as many heat pump systems.

Commercial Water Quality Test (27 parameters). Built for commercial heating systems. It is the only test that measures P-alkalinity, odour, suspended solids, molybdate, silicates, dissolved iron, dissolved copper, total zinc and ammonia. It focuses on system water and does not include a mains comparison.

Commercial Fill Water Test (4 parameters). Checks the water going into a commercial system rather than the system water itself. It tests mains or demineralised fill water for pH, total hardness, chloride and sulphates, so you can confirm fill water quality before or during filling.

System Health Check (26 parameters). Fernox's postal service for diagnosing central heating problems. On top of the Water Quality Test parameters, it adds chloride, excess chloride, lithium, sodium, potassium, boron, sebacate, nitrate and refractive index. These extra markers help pinpoint the cause of a problem. System Health Check is a paper based test, which is not suited for submission in the Fernox App.

Mains water parameters compared (UK only)

Comparing system water with the mains water that fills it shows whether a problem started in the system or came in with the supply. For UK System Health Check and Water Quality Test samples, mains results are taken from the Fernox mains water database, based on samples from the same postcode. The Commercial Water Quality Test has no mains comparison, so it's left out here.

Which test to choose

• Routine check on a domestic system: Water Quality Test.

• Diagnosing a problem in a domestic system: System Health Check.

• Complex faults, glycol systems or the fullest mains comparison: Diagnostic Water Test.

• Commercial heating system water: Commercial Water Quality Test.

• Commercial fill water, before or during filling: Commercial Fill Water Test.

For faster answers on site, Fernox's on-site Instant System Test and Express Inhibitor Test give instant results. Postal tests are the next step when you need a laboratory diagnosis.

Availability

Not all postal water tests are available in every country. For details, contact your local Fernox representative or see Postal Tests Countries & Availability.

* Not applicable for System Health Check