I have a Lennox MPD3530CNM-B fireplace. It is controlled by a standard toggle switch on the wall. I can turn on and off the fireplace even when there is no power. It looks like my fireplace uses a thermopile. As a result, the switch on the wall does not have electricity coming from the electricity panel. The switch on the wall is connected directly to the fireplace.

I am concerned with the fireplace. I understand the Lutron Maestro is an electronic switch. Based on my research, I am not going to be able to use a Digital Switch to operate the fire place.

  • How do I replace a standard toggle switch with a Lutron Maestro 'Digital Switch'? If it is not possible, does anybody know if Lutron has a mechanical switch with look like Lutron Maestro and would do the job?
  • If I ever replace successfully the switch to a Lutron Maestro, will I still be able to turn on and off the fireplace with the switch?

I am in the process of changing the standard toggle switches in my house for Lutron Maestro Digital Switch. My goal is to have Lutron dimmers, switches and wall plate to have a consistent look across the house. That's why I am trying to find a way to power on and off the fireplace with one a Lutron Maestro switch.

I would really appreciate if someone could help me figure out how this would work! Thank you!

  • What wire goes between the flame switch and the lower cavity of the fireplace? Is it low voltage wire? You likely need a relay, the trick is figuring out where you can put it. Yes, I've done this, "Alexa, turn the fire on".
    – Tyson
    Jan 31, 2018 at 12:18
  • Yes, I believe it is low voltage wire. In my case I don’t want a smart switch for the fireplace. Lutron Maestro has smart and non-smart switches which look the same. My plan is to have a non-smart switch for the fireplace and blower.
    – Martin
    Jan 31, 2018 at 14:15
  • 1
    You can't replace the switch with maestro directly, on that side you should just use a single pole decora styled switch, not an exact look-alike to maestro, but it's close.
    – Tyson
    Jan 31, 2018 at 14:19
  • I agree, it's close. But I am updating the entire room with Lutron Maestro and would have really liked to have the same switches/dimmers all around the room.
    – Martin
    Jan 31, 2018 at 14:28
  • 1
    you can have the maestro power an AC/DC adapter that powers a relay that switches the fireplace. don't use a solid-state relay, use a mechanical for guaranteed compatibility.
    – dandavis
    Jan 31, 2018 at 21:48

2 Answers 2


This answer assumes two things; first your #1 priority is a consistent look and second, it's important enough that you are willing to get creative.

Thermopiles generate a small electric current using heat from the pilot light. This current powers an electromagnetic valve that controls the gas. It has been rightly stated that this low-voltage circuit cannot be controlled using the desired digital switch. The circuit requires a single-pole, single-throw mechanical switch.

Here's my solution. Take your brand new Maestro switch and gut it. All you need is the visible exterior and the case that houses the digital goodies. Once the guts are removed, you will need to mount a latching push button switch in the case. This must be done in such a manner that pushing the touch plate will actuate the switch.

I recommend securing the switch into position by filling the case with hot glue. Take a section of open-cell foam that is slightly thicker than the distance required to actuate the switch. Foam is often used for padding in packaging of electronics and optics and such. You have to be resourceful here, find some foam about 1/4" thick. The purpose of the foam is to hold the touch plate in position while allowing the plate to be pushed, actuating the switch. Cut a hole in the foam where the pushbutton will be, glue the foam to the case, then glue the touch plate to the foam.

The finished product will look identical to your other digital switches while allowing operation of your fireplace without external power... all with a simple push on, push off function. Good luck Martin, I hope this helps.

Latching Push Button Switch

  • Thank you @Nathan. This is by far the more creative answer I have ever gotten on this StackExchange. I am not really looking forward to tear apart a $50 switch...
    – Martin
    Feb 2, 2018 at 16:15
  • I completely understand. I produce similar odd-ball solutions working with my clients. The question is then no longer 'can this be done' but rather 'how bad do you want it'. Soooo while installing your electronic switches, should you "accidentally" drop one into your coffee... ahh ha! Thanks @Martin.
    – Nathan
    Feb 2, 2018 at 17:59

Okay, we've established that the Maestro switch cannot serve this application so why involve it? Here's three more solutions:

1- Page 9 of the supplied PDF manual shows an optional control method. It is found in the first wiring diagram. "Twist wires A and B together to operate the unit solely by manipulating the gas control valve knob".

2- Instead of using a toggle switch (which obviously doesn't match your new switches), install a thermostat in its place. A thermostat won't look mismatched because it's not supposed to match. As a bonus, you have added the function of thermostatic control.

3- Drill a hole in the control access door on the front of your fireplace. Install a latching push button switch. They are super easy to install, and they come in an endless variety of styles and finish --chrome, matte, brushed, black, bronze... Just google latching push button switch. It's a cheap, quick and easy way to achieve a clean, low-profile look.

I'm out. Good luck.

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