Abstract: A method of testing central heating system water for concentration of molybdate corrosion inhibitor is disclosed. The method comprises use of a dip test pad to test for iron concentration, and use of a dip test pad to test for molybdate concentration. In assessment of the dip test pad to test for molybdate concentration, the assessed iron level is taken into account. This leads to a more accurate and reliable result than is realised with known dip test.

Abstract: A corrosion inhibitor for a central heating system is provided in the form of a cream having low water content, which may be encapsulated within a water-soluble film, for example a poly (vinyl alcohol) film. The corrosion inhibitor product is more highly-concentrated than known liquid inhibitors, and the encapsulation in a water soluble film provides for safer handling and eliminates waste from plastic packaging.

Abstract: A method of digital assessment of chemical dip tests is disclosed. A photograph of a dip tester including a colour change pad is taken with a mobile device, for example a mobile phone. The dip tester is photographed on or alongside a reference card, with both the dip tester and the reference card in the same frame. A processor on the mobile device analyses the photograph thus obtained to determine a value for a characteristic of water being tested. The characteristic may be for example, pH, concentration of iron, concentration of copper. The water may be central heating system water.