I bought it in the last days of November, installation was done by my own plumber whom I trust blindly… luckily for me, the first 2 days there was a lot of sun and I was able to quickly conclude that the solar water heater had a problem because the water did not go above 20-40 degrees, in other words very lukewarm……I called them, the 1st technician came, checked it, found nothing and left. When I asked him what was wrong, he told me he would inform the company.. 2 days pass, I called them back and they told me they did not see any problem. I call the store where I bought it and luckily they intervened so that a crew could come again to look at it… as soon as the crew arrived and checked it, he told me, friend, the boiler is defective, it’s not your plumber’s fault or anything… they changed the boiler for me, I’m waiting for the results… if anything changes, my review will change too….. 20/01/22 they have changed the boiler, for now it works normally, it has hot water even in the evening hours when the outside temperature is 2-5 degrees… there haven’t even been scattered clouds for me to test it, and so