The most likely problem if you don't have hot water using the electric backup is that a safety switch called the Hi Limit Reset was activated. Turn off the 2-pole breaker in your circuit breaker box for safety, then try this simple procedure that can save you the expense of a $120 service call.
If there is any small dripping after a Solar Hot Water Tuneup, how you can easily solve it.
https://oahusolar.blogspot.com/2019/02/small-dripping-after-hot-water-tuneup.html
How to do High Limit Reset
Please click the useful link for an Important part of your annual maintenance. This is one that you can easily do yourself at no cost, and less than 10 minutes, just make sure you watch out for really hot water coming out of the hose.
How To Do Annual Flush Including Flush and Backflush the Panels
If you have the digital display controller, i.e. the STECA 0103, you can set it to vacation mode. This protects your system from overheating and is a very cool feature.
How to set the digital controller into vacation mode
How to Troubleshoot the Electric Backup Side of a system
