Fireplace automation

Hopefully simple problem here. I am wanting to automate a few things around my fireplace; I do not have any intention of automating the fireplace itself. What I would like to do is have a way to detect when I've turned on the fireplace to trigger the blower on the HVAC to turn on and circulate the air a bit, as well as make sure the mode isn't in Auto (might've had the AC kick on in the dead middle of winter once or twice). I've got a LP vent-free fireplace with no blower connected to a millivolt switch, so no electric whatsoever at the fireplace. I'm trying to find a sensor that is easily hidden; I feel like a temp probe that can detect the rapid change in temperature in the fireplace would be the way to go, but is such a thing made? Or an easier solution that I'm just overlooking?

How do you usually turn on your fire? If you actually have to go up to it to do it, can there be a smart button on the mantelshelf you can press while you are there to trigger the ancillary effects?

I was thinking something with a temp sensor near by. Fireplace heats up = > do stuff. Fireplace cools off => stop doing stuff.

Temp sensor is a good idea anyway, beyond a certain level it might need attention!

Yep, manually turn on and off, but I'm going for something completely automatic for the dependencies. I'd probably remember to hit the button...but my wife on the other hand...

Here's an entire post about monitoring a gas range. Lots of information which I'm sure can be adapted to what you are looking for.

The problem is how hot does it get and were would the sensor go.

When i was looking at addijg a blower to my fireplace pretty much everyone of them came with a sensor to trigger the blower. It was magnetized to attach to the bottom and then when the bottom of the firebox got warm enough it would close the circut for the fan to come on. No adjustments for the temp just when it got warm enough. As far as integrating it with your hvac that would probably require some method of knowing when your fireplace is turned on directly. That would likely mean in a way your fireplace would be integrated. How much would be up to you.

One option could be a zooz zen17. It has two relays that can be no or nc. You could have the fireplace switch on relay 1 as a toggle to know when it is flipped on or off. Then relay two to control the blower. You can integrate either a temp sensor to relay 2 or just set a time in the config or in he to turn on the blower after the fireplace us on. Now that the Zen 17 and in turn HE knows when the fireplace is on you can use it to manage HVAC mode as well.

That's got a few ideas going, most involving arduino. Still can't believe they don't make something with a heat resistant probe that can be used off the shelf and tied in. I feel like I should be able to use one of those water sensors and instead of using the water sensor extension, plug in a temperature probe (sorta like the ones you would use for a grill)

One thing to point out is that a better understanding of what you have that controls your fireplace may help a little bit as well. My suggestion above may not work in some scenarios.

They do make temp probs just for this kind of control. I habe seen them many times as part of a blower kit.

It may even be easier than a smart button. From what I've seen, most gas log fireplaces are turned on by a low voltage circuit wired to a regular light switch that activates the gas valve. A pilot heat sensor/safety is built into the fireplace to prevent the valve from opening if the pilot is not lit.

You should be able to put a z-wave module in the light switch to send a signal when you manually turn on the fireplace. I know this isn't what you wanted (fireplace automation), but not a step much further to add that as an additional bonus.

Power to the module may be an issue you have to figure out assuming there is no power available in the fireplace switch.

I think I may have stumbled on something that would work. Since I have no blower and the only method of turning on and off is a millivolt switch, there's not a real convenient power source. So I'd have to figure the power out, but there's been some ideas thrown out on this thread that have gotten me thinking outside the box a bit more.

Qubino Digital Temperature Sensor ZMNHEA1 for Qubino Z-Wave Modules

This is exactly why i use the Zooz Zen 17, as i use an aux power in the base of the fireplace. I just wired the Zen17 in between the switch and the control module. no wires cut either. I just got some low voltage wire and crimped the right connectors on it. Then used that as a jumper from the Zen17 where needed. All the switch does is tell the zen17 when it as been toggled. Then the zen17 completes the circuit by closing the relay for the fireplace like the switch would.

I can tell you with 100% certainty that the Zooz Zen17 works for this use case.

The fire could be the source of the power. In combination with low power switch (versus using relay), there is away to do monitor (even control the fireplace). I built Zigbee heat powered devices. It has been working great.

More detail here

There is a mode where you can disable Zigbee command therefore you would not be able to operate the fireplace from your Hubitat. However, the wall switch and status of the fireplace is still fully functional. You can use it to automate any thing much faster than monitoring the temperature. The device do measure ambient temperature which tell you the temperature underneath of the fireplace.

This project is in holding pattern for now. I can't find component at reasonable cost to build them. I am just a hobbyist. At this point, I can only share what is possible to do in automating your fireplace.

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I don't have one now but at my previous home we had a gas fireplace. A simple temp sensor on the mantel above the fireplace was my solution. I think I just set it so that if the temp got above 80 or 90 degrees. It's been awhile but the only way the temp would get that high was when it was turned on. I only wanted it to turn on the ceiling fan in the room, which was reversed and set on low. Usually within a minute or two of starting up the fireplace the fan would come on. There are many fancier things you could do but for a simple cheap solution the temp sensor works pretty well

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I think one thing this points to though is a understanding of how the OP's fireplace is wired up. Mine uses a control module and is powered by a dc adapter. It wasn't hard to decifer the wiring, but it certaibly isn't the same for everyone.

There is no electric at the fireplace, they said earlier.

Sorry OP. Didn't connect that dot. So that means some kind of setup with a termopile along with a always on pilot. I like @terminal3 suggestion of a simple sensor on the mantel in that case. That is probably the most straight forward way to do it. And completely independent of the fire place.

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I think that'll be the simplest and best solution; I took a IR gun today and checked, I've got a spot on the mantel that gets fairly warm, but not outside the realm of what I would consider reasonable for a simple temp sensor. It's hidden, and cools off pretty quick once the logs are off. Should be good enough for a recirc fan automation.

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I was using one of the Iris v2 contact sensors. Those were a fairly cheap reliable sensor, I wish they still made them.