There are a few problems that you may encounter when using an above ground solar pool heater. Most of these should be easy to fix and will not require a repairman or a lot of money if you know what to look for. Some of the more common problems people typically encounter with their above ground heaters include low flow rate or pressure, trouble maintaining a proper temperature, and leaks in the solar collectors.
When water is passing through the collector panels, the panels should feel cool. This is a good way to tell if the water is being heated properly. Returning water should be a few degrees warmer than the water in the rest of your pool. Heating the pool a little bit at a time like this is a very efficient way to do it, although it can take some time for the overall temperature to rise.
The pressure on your pump and filter should increase when the system is turned on. If pressure builds up around your filter and the rate of flow seems very low, first check to make sure that the vinyl inlet and outlet caps were removed during installation. If they have already been removed, make sure that they were not accidentally reversed. The inlet should be located at the bottom of the solar panel and the outlet at the top.
Another factor that could affect the flow is a dirty or inadequate filter. If this is the case, clean or replace the filter to eliminate the problem.
There is no point to running your system at night or on cloudy or windy days unless you are trying to cool the water. Since solar power relies on weather patterns to function properly, it will need at least 4 to 6 hours of sunlight every day to be effective.
Before you decide there is a problem with your heater, make sure that the system has been running long enough. Reaching the maximum temperature increase could take up to 5 days of sunlight.
If the water is running through the collectors properly, the panels should be cool to the touch. If they are hot, the water may not be circulating. Check the inlet and outlet as described in the flow rate section.
A slightly more uncommon problem that can occur is leaks in the solar collectors. If your collection panels are leaking water, you will first need to isolate the tube that has the leak. Cut 1 inch off both headers of the tube with a sharp utility knife. Install a #10 or #12 stainless sheet metal screw that is between ½ inch and ¾ inch long in the hole. Make sure not to over-tighten the screw. This should fix the leak. If it does not fix it, you may need to contact a repairman. Usually, performing this operation will not interfere with or void your heater’s warranty, but you should always check to make sure before you try to fix a leak yourself.