thermocouple controlled by a millivolt switch for fireplace

[cseevinck]

This is my first time posting of this board. I am not sure I have the correct place, please advise if I should repost on a different forum.
I have a gas fireplace with a thermocouple that is controlled by a millivolt switch. I have had to replace the wall mounted switch a number of times because the resistance increases over time (contacts getting dirty or whatever). I would like to use a regular switch on the wall that is not as sensitive as a millivolt switch and have the switch throw a solid state relay that will close the circuit for the thermocouple. The regular switch end would be powered by a battery or a transformer. If I get this working I will try to connect a smartswitch to drive the powered end so I can turn the thing on using my phone or a remote control. But my first interest is to get rid of the milllivolt switch.
Any pointers will be appreciated.

 

[audioguru]

I use an ordinary Name Brand light switch for my gas fireplace and it has worked perfectly for 23 years.
Maybe you use cheap ebay switches?

 

[cseevinck]

Yeah, from my reading it seems like some fireplaces have themocouples that behave better, but others are pretty low voltage output and therefore sensitive. I have replaced this switch a couple of times and the second one was from a fireplace outfit, so I think the switch was ok.
Thanks

 

[audioguru]

Smoking and vaping mess up switches and your lungs.

 

[cseevinck]

Haha - only smoke outside

 

[crutschow]

I've also used a standard light switch to switch the thermocouple on my fireplace without a problem.

 

[audioguru]

Ordinary fairly high current toggle switches have contacts made of silver so they can conduct the fairly high current without getting hot.
But silver corrodes easily, it turns black. A fairly high voltage (household electricity) can break through the corrosion but a low voltage cannot.
Then an electronic circuit with a low input current fails when an input switch has corroded silver contacts.
So in electronic circuits I use switches made to work fine with no current or low current. They have gold plated contacts. They cost the same as switches with silver contacts.

Maybe household switches have silver contacts that are gold plated? With a high current then the thin gold burns away.

 

[KeepItSimpleStupid]

It's probably a thermopile rather than a thermocouple.