Popped your question into Google and got this result ............. (@Jim Low )
Yes, the booster switch on a wall for your Rheem hot water system should generally be left on at all times to allow the heater to automatically activate when solar energy is low and ensure you have a consistent hot...
Wooden handles arn't unusual, check the way they are connected to the metal tray, the rivets would just pull through the tin tray. The handles need to go under the tray and support the weight.