Connecting my gas fireplace

Success! I just finished wiring up my gas fireplace.up to SmartThings tonight.

My fireplace as a small on/off switch on the side which is basically just a contact switch. Complete the connect and the fireplace goes on. "It would be easy enough to replace the switch with a z-wave relay, but one thing I have striven for when implementing SmartThings is to ensure that whatever I put in place can not be controlled ONLY via Smartthings. It still has to have a manual control. So, how to put in a relay but still have a functional on/off switch on the side of the fireplace?

Enter the Remotec ZFM-80

This little baby has the option to connect an external switch. So, connect power to the relay, then the replay control wires replace the on/off switch wires. Finally, the switch wires go to the external switch contacts.

Now it works thusly: The relay can be turned on/off via SmartThings, which turns on or off the fireplace. The switch on the side can also be used to turn on or off the fireplace.

Because the relay over rides the physical switch, the switch can get “out of sync” with the actual fire place. For example, if I turn on the fireplace with the switch, and then use SmartThings to turn off the fireplace, the physical switch is still in the on position. Simply turning the switch off, and then back on with restart the fireplace.

Similarly, if I turn on the fireplace via SmartThings when the switch if still off, simply toggling the physical switch on and then back off will turn off the fireplace.

So, one more “things” is gotten smart! Now… how do I my snowblower??


Thanks for sharing, this is pretty awesome.

Too bad the Remotec ZFM-80 does not work like the Aeon Labs Micro In-Wall Switch, which uses the external switch as a toggle switch, so the state never goes out of sync.


Does the toggling of the physical switch register a zwave event? If so, you could (by code) have your smartthings follow along.As for the physical switch, do you have the manufacturers documentation? It seems that you should be able to control it. But maybe not…


I think I’m not explaining myself properly. The switch is a physical on/off switch. It click up for on, down for off. Obviously when the relay is turned on or off wirelessly via SmartThings, the relay can’t change the physical switch.

But, this isn’t really a problem. The relay knows the difference between the on and off position. If the fireplace is on while the switch is off, flipping the switch to on doesn’t turn off the fireplace. Flip the switch back to off will turn off the fireplace.

And now, just for the fun of it, I created a new device type. Identical to the normal Z-wave switch except for one minor change. The background color when the switch is on is now Lava Red:

I’ll have to see if my fireplace will work with this. I have a wall mount mechanical timer type switch:

But I think it just carries a very low voltage down in a single wire. Probably not enough to actually power the z-wave switch.

Probably a very similar setup to what I’ve got @imbrian.

The physical switch on the side of my fireplace just closes a low voltage loop that turns on/off the fireplace. If you can get at the guts of your fireplace see if you can find where those wires tap into. Take off the wires leading to the timer and replace with the relay wires from the Remotec device.

Of course, this assumes that there is a spot to grab normal house power from. In my case I’ve got an outlet behind the fireplace that runs the fans motor for the fireplace so I just plugged into that.

Then you can mount your wall switch to the “switch” contacts on the Remotec relay. You’ll probably want to replace the timer with just a standard on/off switch.

Yeah - I don’t have power convenient anywhere nearby :frowning:

I could route a wire 4 or so feet - but something tells me the wife would veto that.

Ah, well, crap… that stinks. Yeah, without the power the z-wave doesn’t work.

That’s actually going to be a minor issue for me with my setup now too. Previously the fireplace would still work without power. The blower fan wouldn’t of course, but flipping the switch on the side would still work. Now because that switch runs to the relay if we lose power the switch will be dead.

Fortunately there is still a pretty easy way to turn on the fireplace without power… just have to remove one snap in panel and flip an internal switch.

I wired my relay in series with the existing switch. This way I can use the physical switch to be a kill switch for relay. In other words…if I turn off the physical switch the fireplace will never work. For the z-wave relay to work I must put the existing switch in the on position.
So if I want to use the wall switch the z-wave relay must be on, also.

You could rewire your relay in parallel with the existing switch and it would never get out of sync. This way you could use either the existing switch or the z-wave relay.

Just put the existing switch back like it was and do not use the remote switch feature on your ZFM-80. This way it will work without power…


Thanks for the suggestions, but there’s disadvantages to this ideas for my setup too.

First, I think I did a bad job of explaining the “out of sync” thing. It really isn’t a major problem. The relay knows the difference between the switch’s on position and the off position. So let’s say the switch is off on the fire place. I use SmartThings to turn on the fireplace. Now the physical switch is “out of sync.” So if I flip the physical switch to on… the relay doesn’t nothing. The relay says: “I’m already on.” Then when I flip the physical switch to off, the relay turns off. So it’s never really out of sync for more than one flip of the switch. Likewise if the switch is on and I turn off the fireplace with SmartThings. Flipping the physical switch to off does… nothing. Then when I flip the switch back to on the relay clicks on.

Second, my wife is NOT a gadget geek like I am. While she does appreciate some of the benefits that SmartThings has brought (probably more than she’d be willing to admit really), she also would NOT approve of a setup that required her to use SmartThings. So, the serial idea, or the parallel idea wouldn’t really work.

With serial she could turn on/off the fireplace if the relay was on, but if I turn off the relay in SmartThings then the switch because useless. Additionally, if the switch it turned off I can’t remotely work the fireplace.

In parallel then the switch and relay work independently of each other, but if one has the fireplace on, the other can’t turn it off.

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Would the Fortrezz MIMOlite work on this? I have the same configuration for my gas fireplace, a switch that is either on or off to turn the fireplace on. Thanks in advance from a newbie

link -



I think so… I looked over the user manual for the Mimo here ( and it looks like the SIG1 inputs will work for an external switch. I don’t have one of these relays myself so I can’t say for certain, but it looks like it would work.

I started looking at making my fireplace “smart” today as well and got all caught up on this thread. Here’s the basic summary of what I’m seeing. People are trying to use some sort of combo zwave switch with remote to make their fireplace “smart” plus have a manual switch nearby. The issue is that the two switches don’t know what each other are doing and thus sometimes are out of sync.

Has anyone attempted a solution with the smartthings arduino shield? Seems it wouldn’t be too hard to make a smartthings arduino shield that you could stick down in the inner workings of the fireplace to control the flame. If you have 110V power down there great. Put a transformer on it and power your arduino. if not battery powered arduino works too. The arduino has an output to control a relay for the flame and an input to sense the state of the manual switch. Since the arduino is the central place that processes the flame output there is no “out-of-sync” issue.

Figured I ask if this has been done first. My current arduino shield is still in use testing for a garage door opener integration. Maybe I’ll have to re-purpose it soon for the fireplace…

@gilm0079 - I’ve thought about the battery powered arduino approach as well. I do not have power routed through (just a very low voltage contact mechanical switch). I’d be interested to know if that low power contact is enough to power a small arduino, but I suspect it is not.

For me, the interest in a remote fireplace was outweighed by my lack of motivation and extreme aversion to soldering (I’m really really bad at it). I’m also not too keen on having exposed electronics dangling out of my wall - and don’t want to take the wall apart to change batteries.

I’ll keep monitoring this thread in the hopes someone finds a good solution, but until then, I’ll be ok with my dumb fireplace.

I ordered the MIMOlite and it should be coming in this week. I am going to try it out with both my fireplace and also with my garage door opener. I will let you know my findings of compatibility


I’ve got a MIMOlite connected to my gas fireplace and it works very well. I’ve had it installed for about 3 months. I also used a z-wave dimmer to control the fan speed. I feel Jethro from the Beverly Hillbillies when he was trying to be a swinger at Dash Riprock’s apartment. I can push a button and the fireplace lights the Hue lights dim and to change colors, and soft music starts playing. I wish I had all of this when I was in my early 20s.

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@Brianh - did you just wire up the MIMO to the fireplace using the com1 and nc posts?

@Jake - I connected COM1 and NO. NC would cause it to be closed all the time (fireplace on) and Smartthings would open the circuit. The circuit is Normally Open and then Smartthings will close the relay until it’s opened again. Then just run those wires to your switch connections on your gas solenoid. You can keep your switch attached and just run these wires in parallel that way you can operate by ST or switch. Here’s a pic of my setup

MIMOlite fireplace wiring

@Brianh - Thanks so much. Fireplace is up and running!