Fitting a solar panel on your roof to heat the water is great but don’t forget that it will require maintenance. Solar power, and that includes solar panels do need to be maintained. At least once a year you should be checking it over for leaks and the level of antifreeze in the circuit to make sure it can take the winter. It’s all very well having an air vent on your solar panel but who wants to go up on the roof every time you need to re-fill or top up to bleed the air off.
Whatever the reason, a bit of thought at the design stage can make life easy. By incorporating three isolator valves in the correct places, and with a bucket and a small submersible pump you can make the job of checking, filling and bleeding your system quick easy and trouble free,
The design revolves around using three isolating valves (you could use ball valves if you prefer). Using a tee on the return pipe, quite close to the exit from the hot water cylinder, place an isolator valve on the open end of the tee and a second isolator valve in the pipe going from the tee to back to the solar panel. My third isolator is in my filling loop that feeds into the expansion vessel. The isolator valve on the open end of the tee also serves as a tap for a drain point should I need to drain the system.
To fill the system you use a bucket, a small submersible pump and two lengths of garden hose pipe. If required, mix up your antifreeze/water solution in the bucket. You will need an extra 2 or 3 litres of solution to make sure the base of the pump is covered when the system is full. Using two lengths of garden hose pipe, connect the pump output to the filling tube and the other length of hose to the drain point. This hose is then a drain back into the bucket.
By opening the valves on the drain and the filling loop and closing the valve in the return line, the water can be forced around the circuit and discharged back into the tank through the drain. Make sure the drain is below the level of the water so you can see when the air bubbles stop, indicating that there circuit is full of water and any air has been discharged.
Once you are happy that all the air has been removed, close the two open valves and open the return line valve. Allow the pump to pressurise the system. Submersible pumps don’t produce much pressure but are adequate for a solar panel circuit. Mine will charge the circuit to approximately 0. 5bar.
And that’s all there is too it. We go into more detail on our website http: //realityGreen. co. uk/solar. aspx where illustrations and photos are also included.
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