Solar system experts here's your question.
I have Heliocol solar system on my roof to heat the pool. I have recently switched to a VS pump which also handles circulation in the solar system. There is a relief valve at the top of the solar panels located furthest from the riser to the roof. My understanding is that it is there to allow air to enter and bleed the panels back to the pool when the pump is shut down. My question is does it also bleed the air out on start up? I know that I see a lot of air bubble out in the pool when the site first starts, but is air also bled through this valve?
I understand that in a closed system, once the panels and all plumbing is filled with water, there is no loss due to elavation. I also understand that I need to initially ramp up the speed of the pump to fill the panels and push out any air. My problem is that I need to continue to run at a relatively high rpm to keep that valve closed to prevent air from entering the system and stoping circulation. If that valve is there only to allow for draining the panels on shut down, why couldn't it be relocated to a much lower position, like the riser going up the side of the house. That way it would take about 6 psi less pressure in the system to keep it closed. But if I do that will I be trapping air in part of the system on the roof, preventing circulation in a potion of my panels?