There are a few potential reasons why your solar water heater might not be working. One possibility is that there is something blocking the sun's rays from hitting the panels, like a tree or building. Another possibility is that there is something wrong with the panels themselves, such as a crack or hole. Finally, it's also possible that there is something wrong with the system's wiring or plumbing. If you think that there might be something blocking the sun's rays from hitting the panels, try moving them to a different spot where they can get more direct sunlight.

It's likely that your solar water heater has just stopped working because of a lack of sunlight. Solar water heaters work by absorbing the sun's rays and converting that energy into heat, which is then used to heat up the water. If there isn't enough sunlight, then the solar panels won't be able to generate enough heat to warm up the water. There are a few other reasons why your solar water heater might not be working, such as a clogged filter or a broken pump. If you think that might be the problem, then you can try disassembling the solar panel and cleaning out any debris that might have accumulated. You can also try checking if the pump is still working and replace it if necessary.