Solar panels on very steep roof

Does anyone know if there's an issue with installing solar heating panels on a steep roof. I estmate my pitch is 14/12 (rise/run). All I can think off is reduced efficiency due to the high angle and increased back pressure due to the higher head. I have a 1.5 hp pump, btw. This section of the roof is the closest to the pump, starts at one stpory up, and is the only viable location. The rest of the roof is two stories up and would probably require a new pump.

Installation is certainly harder but I think you have it right in that the efficiency is the biggest impact. However, that could be a positive in lower sun elevation angles so you might end up with a more extended season than if you had a flatter roof.

BTW, I just converted my 1 HP pump to a 1/2 HP two speed and the solar panels prime just fine at 25' so your 1.5 HP should do fine on the second story roof.