A pump is required to move the water and antifreeze mixture around the solar system. It is this movement that allows the energy captured by the solar panel to be transferred to the hot water tank. As the solar system is pressurised there is a need to install a pressurised system kit. this comprises of the following components: filling loop (incl. double check valve, flexible hose and shut-off valve); pressure gauge, 3 bar pressure relief valve, air vent and an expansion vessel incl mounting bracket.
Pumping Stations are basically all the above components packaged together ready to be installed and although more expensive than buying the individual components the installation time is significantly reduced along with the possibility of leaks as they have already been pressure tested. The controller can also be installed in the station or be located remotely.
It is possible to connect up the solar system with combination of 15mm and 22mm copper pipe and insulate it with a high temperature pipework insulation such as solar rated Armaflex. We don’t use the insulation that you find in DIY stores as it cannot cope with the high temperatures generated by the solar panels and will melt!!
However there is an alternative to copper pipe which is a corrugated stainless steel pipe already inside high temperature insulation that is flexible. Although more expensive than the copper pipe option it is possible to run directly from the solar panel to the tank and pump without any joints providing ease of installation and drastically reducing the possibility of leaks at joints.
Although insulated there is a small ammount of outside pipework and water running through the manifold it is wise to add antifreeze to the water just to ensure that there are no freezing problems.
Thermostatic Mixing Valve
By adding a thermostatic mixing valve to your vented hot water tank (thermal stores have one as standard) you can heat the water to a higher temperature than normal therefore getting the most of the solar panels. When there is a demand for hot water the mixer valve reduces the temperature to a predefined temperature by mixing with cold water before sending to the taps.