Logic Help: Run fan when hot, 15 min per hour

Hello- new to Rule Machine, hoping for some help on a logic problem.

Need: attic fan on a zwave switch should run for 15 minutes once an hour if the temp on the attic sensor is > 30 degrees than the temp on the covered patio sensor.

I can find how to flip a switch based on meeting the higher temp condition between two sensors, what I can't find is how to set the fan=on run time of 15 minutes once an hour and repeat logic to the rule.

Any thoughts?

Fan is on an Aeotec HD zwave switch, temp sensors are Inovelli 4-in-1 zwave sensors

You have two ways to approach this:

  • You can trigger every hour
  • You can trigger every temperature change

I prefer triggering once an hour. It is likely to be much more efficient because there should be far fewer events to subscribe and handle.

So, you create a trigger that runs once an hour (periodic trigger on hourly).

Then in your actions you use conditional actions. You create a condition for if the sensor difference is greater than 30 degrees (temperature relative to another device with an offset of 30).

Then you set it up in the conditional actions. Turn it on if the conditions are met and then turn it off with a 15 minute delay. Here's a fake POC.

image

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Ah ha! I never thought to look at this as a timer with a device action, only as a device that needs triggering with a timer attached. I think I got it. Many thanks!

Screen Shot 2020-05-13 at 9.01.50 AM

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I upgraded this logic a bit more to include a high humidity condition that would run if attic is 75% humid or more, but only if it isn't all that humid outside. There are separate rules to pause and resume this rule based on time of day, so it wouldn't run in the middle of the night.