I've been assuming that the increase in my power bills was due to increases in oil prices. But upon turning off the the power to the hot water heater in order to rely solely on solar, and running out of hot water seemingly way too soon especially given the sun this time of year is nearly straight up at noon here in Hawaii, I took a closer look at the installation that was done on my system a couple years ago.
I noticed one thing in particular that did not seem right to me. There is a check valve mounted just above the 'out' connection (back to the solar panels, right?) that appears to me to have been put in backward. The arrow is pointing opposite the direction of (assumed) flow, is it not? I've attached a couple pictures:
Thanks to anyone who might be able to offer some advice on this! I'm trying to gather information before calling back the contractor in order to hopefully be in an informed position.