Water Heater Timer 3001

Not sure where exactly to put this topic, so please correct me if i posted in the wrong area.

For the last few years I had a homemade solution to shut off my natural gas power vent water heater at night. This wasn't done to save a few pennies, but rather to avoid having to hear the water heater kick on occasionally in the middle of the night.

The way my setup worked was that a timer activated an appliance relay that opened a Normally Closed (NC) contact that turned off the water heater 120VAC supply. Easy enough, but I also put in a current sensor wired to another relay that would keep the water heater running if it turned on during the shut off time. Example, doing a load of laundry at 8:55PM and the water heater was set to shut off at 9:02PM, if the water heater was already running it continued running until it was done with its cycle.

I have managed to recreate this feature using a Sengled Smart Plug E1C-NB7 and the built in power monitoring features. It took me a LONG time to figure out the rules, the biggest hurdle to get over in Rule Machine was the difference between "Wait for Event" vs. "Wait for Expression".

I will attach a screen shot to show what I did, hopefully it is helpful to others.

Picture of the old setup vs. the smart plug:

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Schematic of old setup:

This post really helped wrap my head around the differences in "Wait for Event" vs. "Wait for Expression": Remind me about the subtle differences in different kinds of waits - #2 by bertabcd1234

The big thing that was causing me to stumble, I was waiting for the event of the power going to <100. This meant that the rule, once triggered, was always waiting for that to happen. This worked great when the rule was triggered by the heater turning on. It didn't work, though, for my desire to turn off the water heater at 9:02PM whether the heater was on or not. The rule would just sit there and wait for the heater to first turn on and then turn off again, not what I wanted. By changing to wait for expression, when the power was <100 the expression was true, even if that happened well before the rule was triggered.

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I did something similar. Hot water is fine and its using the low energy tariff