flame roll-out switch (gas heat? It's not safe)!

Xringer · 09-17-11, 06:17 PM

I have very little experience with gas heat. But, my only child thinks I'm an HVAC guy.?.

And, her Freedom90 single stage system was not heating (3 flash error).

Here a copy of some of the email I sent her today..

~~~

The suspect air pressure switch looked okay on the ohm meter.

Then I started checking all the temperature sensing switches.
I applied a little heat to each one (BBQ lighter) and they seemed okay,
except for the last one. The flame roll-out switch!

Furnace - Wikipedia, the free encyclopedia
"The limit control is a safety device that will open the electrical circuit to the ignition control and stop the gas flow if the furnace overheats.
The flame roll-out switch does the same thing if the flame was rolling out of the heat exchanger instead of being completely induced into it by the draft inducer."

I saw the tiny red button, and realized it had to be the flame roll-out switch shown on the wiring diagram.
The switch did not respond to heat at all. The red button didn't do anything.
I figured it would need to be replaced, so I really pushed and pulled hard on the button..
And then, it CLICKED!! Dang, it was reset!!

I re-installed it and still no luck... So, we let it rest for a while, and turned off the upstairs thermostat.
When I turned it back to heat, it started up and ran the heat..
After a 10 or 15 minutes, it shut down.?. I got my meter and headed back down to check the flame roll-out switch..
But as I stepped towards it restarted! (Is this it's normal cycle)?
It ran for about an hour without failing. House was 66F and it climbed to 72F.
(I put your thermostat back in cooling/program mode, where it will cool at 79F, as it was before).

1. We need to replace the flame roll-out switch.

2. It might no be a flaky switch, but the flames are ROLLING back out of the heat exchanger! (Where they should not be)!

We don't know IF your furnace over-heated or not.. (It seemed to run fine today).
So, this something you need to keep an eye on. Don't run the heat if you are not home.
If it fails, we can't just keep resetting it, just in case there is a serious flame problem.

I will try to get a new switch and get it installed ASAP. But, I would think seriously about
getting a service contract with a yearly maintenance tossed in.. (Cleaning etc)..

Here's the informative video.. Flame Roll Out Switch - YouTube

Ryland · 09-17-11, 06:48 PM

This is part of why we opted to have our furnace cleaned and inspected, they check and replace any safety switches that might wear out, they clean, check and adjust the burners and make sure that the exhaust has the right o2 content, checked the heat exchangers for leaks or thing spots and at least the folks we had do our furnace also gave us a warranty of one year that would cover any repairs or replacement that we might need.
Our furnace is a sealed combustion furnace from 1987, so a warranty on it seems like a great deal.

09-17-11, 06:17 PM	#1
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	flame roll-out switch (gas heat? It's not safe)! I have very little experience with gas heat. But, my only child thinks I'm an HVAC guy.?. And, her Freedom90 single stage system was not heating (3 flash error). Here a copy of some of the email I sent her today.. ~~~ The suspect air pressure switch looked okay on the ohm meter. Then I started checking all the temperature sensing switches. I applied a little heat to each one (BBQ lighter) and they seemed okay, except for the last one. The flame roll-out switch! Furnace - Wikipedia, the free encyclopedia "The limit control is a safety device that will open the electrical circuit to the ignition control and stop the gas flow if the furnace overheats. The flame roll-out switch does the same thing if the flame was rolling out of the heat exchanger instead of being completely induced into it by the draft inducer." I saw the tiny red button, and realized it had to be the flame roll-out switch shown on the wiring diagram. The switch did not respond to heat at all. The red button didn't do anything. I figured it would need to be replaced, so I really pushed and pulled hard on the button.. And then, it CLICKED!! Dang, it was reset!! I re-installed it and still no luck... So, we let it rest for a while, and turned off the upstairs thermostat. When I turned it back to heat, it started up and ran the heat.. After a 10 or 15 minutes, it shut down.?. I got my meter and headed back down to check the flame roll-out switch.. But as I stepped towards it restarted! (Is this it's normal cycle)? It ran for about an hour without failing. House was 66F and it climbed to 72F. (I put your thermostat back in cooling/program mode, where it will cool at 79F, as it was before). 1. We need to replace the flame roll-out switch. 2. It might no be a flaky switch, but the flames are ROLLING back out of the heat exchanger! (Where they should not be)! We don't know IF your furnace over-heated or not.. (It seemed to run fine today). So, this something you need to keep an eye on. Don't run the heat if you are not home. If it fails, we can't just keep resetting it, just in case there is a serious flame problem. I will try to get a new switch and get it installed ASAP. But, I would think seriously about getting a service contract with a yearly maintenance tossed in.. (Cleaning etc).. Here's the informative video.. Flame Roll Out Switch - YouTube

09-17-11, 06:48 PM	#2
Ryland Master EcoRenovator Join Date: Mar 2009 Location: Western Wisconsin. Posts: 913 Thanks: 127 Thanked 82 Times in 71 Posts	This is part of why we opted to have our furnace cleaned and inspected, they check and replace any safety switches that might wear out, they clean, check and adjust the burners and make sure that the exhaust has the right o2 content, checked the heat exchangers for leaks or thing spots and at least the folks we had do our furnace also gave us a warranty of one year that would cover any repairs or replacement that we might need. Our furnace is a sealed combustion furnace from 1987, so a warranty on it seems like a great deal.