I have the aforementioned device installed in my meter box and connected to my Hot Water system.
How I want to configure it is to turn off during the day and then turn on during the night, I also want the ability to be able to turn it on manually as an override if I know I am using a bit more hot water than normal.
Automating the on/off at certain times I can do, however what I am not sure of how to do the override and stop/start the automation.
The other fear I have is that if something happens to my HA or my network and the 1PM is turned off, how to I turn it back on?
If it matters, my electrician put a circuit breaker before the 1PM and connected it to the circuit breaker of the Hot water system.
It sounds like you already have the solution. And if you stick with the Native Shelly firmware then you have direct access via a web page to the device to control it if HA is otherwise down. If your network is down but the power is up, Shelly also has it’s own access point so you can connect to the internal wifi. Shelly stuff really is quite good, I use a lot of them and while I swore I would never go WiFi and stick to Z-Wave and Zigbee, Shelly changed my mind.
I have a Shelly Pro 1 wired to control a 20A Normally-Closed contactor, this means if the Shelly fails the default state will always leave the Hot Water on. Our Hot Water system draws current near the max rating of the Shelly so this allowed for a bit of a buffer.
For the override you can try creating a helper switch and use as a condition and trigger to control the Shelly.
If you want a physical button as well, you can find DIN-rail push-button switches around that you can wire to the Shelly inputs.
I am looking at similar setup. Agree with Joddy that with a standard HWS at 3600 Watts, that a contactor should be used. With Fronius inverter you can also use configurable load management to open relay when excess power is generated.