Hi Guys, I have just put borrila in roof solar panels on and I have nearly finished piping up the solar connections on the cylinder. The pumping station won't be conected to the electricity for a couple of weeks and there is no water supply to the unvented cylinder yet. Is it better to fill and vent the system with glycol or leave it empty. I was planning on filling it tomorrow but I'm not sure what's best to do? I don't want the sun damaging the panels is it better if there empty or full with no pump connected?