We have a solar water heating system.  A few months ago we started noticing that the water isn't as hot as it used to be.  Around the same time I noticed that the water heating panels on my roof were stuck in the "up" position and I haven't seen them articulate back to the "flat" position. 

The water starts off really hot, within 30 seconds it becomes luke warm and I have to adjust the knob to a hotter setting, a few minutes later it becomes luke warm again and I need to adjust to a further hotter setting.  By the time my shower is pau, I have the water temp knob at the hottest setting, the setting where normally it would be hot enough to burn skin.

Anyone here know about water heaters or solar water heaters? 
I don't know much but I can suspect a few things:
1. the solar panels are defective
2. the water heater is defective
3. the low winter sun threw off the heat or timer settings

Is there a way to adjust the heat or timer settings?
Help needed!  Thanks a lot folks! 

Not a solar specialist by any means either but…

I would think if the panels are not laying back flat you are not getting the best angle for the sun to catch the panels. I never knew that they can articulate, is that something they do automatically based on the angle of the sun? I guess you would need to get a pro to see if the panels are bad. Not likely though in my opinion if your system is not at or beyond it's "life expectancy". I would check how clean or dirty your panels might be, too. They tend to build up dirt, grim and mold that can drastically reduce the solar panels efficiency.

Good luck…hot water good.

Check to make sure that the pump is running during the day.  There is a temp sensor at the panel and one at the water heater.  When there is a certain temp difference between the two sensors (mine is 15 degrees) the pump will turn on to circulate the water.  The pump usually runs for about 1 minute.

Check to make sure that the pump is running during the day.  There is a temp sensor at the panel and one at the water heater.  When there is a certain temp difference between the two sensors (mine is 15 degrees) the pump will turn on to circulate the water.  The pump usually runs for about 1 minute.

 in my opinion if your system is not at or beyond it's "life expectancy". I would check how clean or dirty your panels might be, too. They tend to build up dirt, grim and mold that can drastically reduce the solar panels efficiency.

+1++1 =+2

The other thing to check are the dip tubes.  Plastic tubes inside the tank (accessible from the top) that send the cold water to the bottom of the tank and pull the hot water from the top of the tank (cold water sinks and hot water rises)  If the tubes are broken the hot and cold water will mix and give the symptoms you describe. The the dip tube for the solar pump goes about halfway down the tank and the return from the panels is shorter. Cold water inlet (from street) is the longest.

Thanks folks!  I'll check to see if I can find said sensors, panels, and dip tubes, and let u know. 

Additionally, the system is not at life expectancy, at most about 6 to 8 years old.