SIT 820 issue

[tdalton]

I have a gas fireplace with a SIT 820. The house was built in 2003 including the installation of the fireplace. It worked fine for 13ish years and then the pilot light wouldn't stay lit. I had someone look at it and he filed the pilot light area with flint paper and it worked for a short time but then reverted to the pilot light not staying lit for more than a couple of minutes. I disconnected the gas line and blew it out with air using a pump and it didn't fix the problem. I planned on just replacing the SIT 820 unit but wanted to check here for anything else I might be able to try before doing that. I also read some posts on replacing the unit but haven't been able to find a comprehensive install guide or video so I'm not too clear on the process of removing the old one. Thank you in advance.

 

[Lennox65]

The Thermocouple is the element that ,when working properly, provides the small amount of voltage(generated by the pilot flame) needed to hold open the pilot side of the gas valve. They do have a lifespan, and 20 years is just about at the outside of that span.
The Thermopile which performs a similar function for the main burner side of the gas valve typically wears out at around the same time.
The best thing to do is to replace the entire pilot assembly.

 

[tdalton]

Thanks. I'm still looking for a tutorial. I've read on various forums it's easier to take the whole fireplace assembly out than it is to do it while installed on your stomach but haven't been able to find any videos or writeups.