Reason 1. The solar water heater has something covered or the tubes are dust.
Solution: Take off the cover, install the solar water properly in a good position, and clean the tubes.
Reason 2. The solar water heater installed a wrong direction.
Solution: Install the solar water properly in a good position; please check more details in the installation part.
Reason 3. Up water loading valve not closed
Solution: Close the up water loading valve when the tank is full.
Reason 4. Water tank is empty, water pipe leak or transfiguration.
Solution: Check the water pipe, if ask a plumber for a help.
Reason 5. Water pipe assemble wrong
How to make sure solar water heater is working?
Test it in a sunny day.
1. Fill the solar water heater in the early morning and Switch off the inlet and outlet till late afternoon. Then check the water temperature at 5 or 6 pm. If the water is hot that's means the solar water heater is working.
2. Not use the hot water check the water temperature again in the next morning, if the water still hot that means the insulation is good.
3. Check the inlet water pipe and outlet pipe and electromagnetic valve