Purging air from DIY coil solar pool collectors

[skeeter_ca]

I am building a DIY solar pool heater. The system uses 8 coil(irrigation tubing) type collectors.They are being mounted on a stand about 20ft from the pool and about 5 feet higher than the pool. Since it only has a 5 foot rise i wasn't thinking off using in an air break.

I am having two design questions. Should i have the exit on the collectors at the top so air will purge out of the top? I have seen both top and bottom exit with no problems mentioned. And second, how does the return header purge any air out of it?

skeeter

[Naptown]

As long as there is enough water pressure and volume it will purge itself.