A case of defective plumbing work in Solar Water Heater has come to our observation in a 300 Litres Per Day (LPD) system installed at Rajkot.
This piping was done an installation of solar water heater without overhead cold water tank. Actually in this type of pipe fitting, when customer uses hot water from the solar tank, water level in the solar tank reduces gradually and solar tank gets empty after complete hot water is drained from the solar tank. Then after, cold water has to be pumped into the solar tank by electric motor or submersible pump, so that water in the solar tank is transferred to solar tubes and it gets heated by thermosyphon principle.
In this type of installation, generally CPVC pipe are used for cold water inlet. Snap shown below already has the CPVC pipes used for cold water inlet in solar tank, but plumber has made one mistake. He has put the joint of APVC and CPVC at slight upper level, due to this thing happened that during summer, vapour entered the APVC pipe (which is generally used only for Cold water piping) and APVC pipe got bent, leading to stretching and bending of CPVC pipe used for hot water inlet in solar tank. In areas of excessive heat during summer season, it is also advisable to cover the solar tubes with any obstructions like thick cloth or blanket so that water in solar tank don’t get overheated. This precautionary measure will also increase the life of Solar tank and solar tubes will also not require frequent servicing due to scale formation.