Quadrafire Castille thermocouple issue

Hi folks - After replacing a thermocouple and an ignitor that were both visibly failed, I was not able to achieve a green or red tcpl light. I get a yellow failure light when I unplug the tcpl for testing (13mv) but it never turns on the green. I replaced the board with the same results, and retested /recrimped the connections. Remember, we get the yellow light if I break the tcpl connection, so I know it is communicating with the computer. There is 13mv from a hot tcpl, and swapping computers gives the same result. Tcpl touches the cover, which protrudes 1.75 inches. I would have tried swapping the polarity on the tcpl but the wire colors were correct. Any ideas? After 30 years of working on these things, I'm stumped.
Thanks
Kevin

Hi Kevin
If you are getting the yellow light (or as Quadrafire calls it the Amber colored light) on the control box when starting, this error light is only for a bad thermocouple. I just wrote comprehensive troubleshooting directions for that, so here it is below:
How do I know if I need a new Quadrafire Thermocouple?

• First make sure the venting and stove is clean. Also make sure the fire door and ash pan gaskets are good and they are latched tight.
• Check to see if there are pellets in the hopper. If it did run out of pellets then hit the reset a few times to fill the auger chute to see if they start dropping. There are basically 2 possible reasons for the thermocouple error:
• If you get the standard Amber colored light flashing error on the clear control box, it is a Quadrafire thermocouple error. After the stove is turned on, the blue light will flash, then the amber light will flash 3 times. See video of thermocouple error: https://www.youtube.com/watch?v=2_qj7lN71F8 If the stove does not fire up after the blinking yellow light, this means that the thermocouple is somehow disconnected from the control box. The horseshoe connectors that slip under the black screw terminal block are loose or broken, or the wire itself is severed. It is also possible that the connectors inside the metal box that protrude out of the back of the black terminal block have a bad connection. Unplug them and plug them back in to check. Breaks often happen inside the thermocouple cover from the intense heat from the fire. Remove the cover to check.
• If the stove does fire up and will not continue to run but can be made to run by pressing the reset button and it feeds more pellets. This is still a bad thermocouple but the wire is not severed, so there is no 3 flashes of the amber light. First make sure the end of the thermocouple is pushed all the way into the thermocouple cover. If that is the problem, purchase the upgraded thermocouple bracket here to fix it. https://www.eastcoasthearth.com/products/quadra-fire-thermocouple-uograded-holding-bracket-812-3171?_pos=1&_sid=85cb5612a&_ss=r If that does not keep the pellets feeding after firing it up then replace the thermocouple. The best way to test this thermocouple is to measure the voltage: This K type thermocouple voltage changes 40 uV per degree C. In startup mode, the green light turns on at about 2.7 mV (+/- 0.5mV) which indicates startup mode; the red light turns on at about 12.0 mV (+/- 1 mV) to indicate run mode. Therefore in run mode a good flame of 1,000 Deg C should read about 30mv. If you read anywhere from 12 mv to 30 mv then you are in the ballpark. If it reads less than 12 mv with a good flame, then it should be replaced.

You can order the thermocouple here:
Quadra-Fire Thermocouple 34-3/4" long for large FS stoves 812-0210
https://www.eastcoasthearth.com/products/quadra-fire-thermocouple-34-3-4-long-812-0210?_pos=3&_sid=e2cbda1e3&_ss=r

14" long for smaller stoves - see model #s in link below
https://www.eastcoasthearth.com/products/quadra-fire-thermocouple-14-long-812-4470?_pos=1&_sid=e2cbda1e3&_ss=r

FYI
Quadra-Fire® Classic Bay 1200 Pellet Stove: Operation Video - YouTube
https://www.youtube.com/watch?v=vUE8cHUE65E

One final note, if a brand new thermocouple does not work, try reversing the leads where it is connected to the terminal block. The wiring on some stoves may vary, so you'll have to switch the leads.

My QuadraFire Castile does not have a terminal block. I’ve tested the brand new thermocouple and it tests good. I’m wondering if swapping the leads as you’ve stated would work ? I’ve spend so much time troubleshooting this stove testing and replacing parts…it’s getting old !

Yes, try swapping the leads because they can only go one way.

Hello - I have a quadrafire pellet stove. It was in the house when we moved in and don’t know too much about it’s origin. I clean it weekly during the season of use and have not had any issues.

As we have just begun using it, I am finding that the stove is starting up and running for some time without issue. It will stop dropping pellets as if it reached its heat and then there will be a yellow blinking light with the red one on as well. I have looked at the hearing element and ensured it’s on tight. It starts up and works but then will stop. Help!

Hello,
The yellow light indicates a bad Thermocouple.The red light just means there's a call for heat; the thermostat is telling the stove to heat up. Make sure the Thermocouple wires are connected properly. In some rare cases it can be the control box. Here are some links to the Thermocouples with different length wires. Models for each are in the listings:

14" Thermocouple:
https://www.eastcoasthearth.com/products/quadra-fire-thermocouple-14-long-812-4470?_pos=1&_sid=6151c1be8&_ss=r

34 3/4" Thercocouple:
https://www.eastcoasthearth.com/products/quadra-fire-thermocouple-34-3-4-long-812-0210?_pos=3&_sid=6151c1be8&_ss=r

Hello! I have a classic bay 1200i that I had to replace a convection blower as well as a control box. Now when I plug the stove in an amber light comes on for a few moments, turns off, then the stove starts its regular blue blink sequence. No pellets drop, but the igniter does get hot.
Is this indicative of a failed thermocoupler as well?

Hello
If the amber light comes on, usually it is a bad thermocouple. That will stop it from feeding pellets.
However, a bad vacuum switch and a tripped high limit switch can also do that. So try the reset button on the high limit switch and go from there.

Hi Don
I was directed here by Mt Bob, as I'm having the same trouble as Kevin, above. Was his issue ever resolved?
Your excellent write-up on the thermocouples pretty much matches what I've observed in troubleshooting my problem. If you have time, I would really appreciate it if you would check out my thread at https://www.hearth.com/talk/threads/classic-bay-1200-stove-shut-down-problem.198191/#post-2661119 and let me know what you think.
Thanks, and have a great day.
Mel

Here is what I posted in reply to your post.
Did you try bypassing the vacuum switch, they can fail when the stove heats up.
Also check the snap discs.

Anonymous:
Hi folks - After replacing a thermocouple and an ignitor that were both visibly failed, I was not able to achieve a green or red tcpl light. I get a yellow failure light when I unplug the tcpl for testing (13mv) but it never turns on the green. I replaced the board with the same results, and retested /recrimped the connections. Remember, we get the yellow light if I break the tcpl connection, so I know it is communicating with the computer. There is 13mv from a hot tcpl, and swapping computers gives the same result. Tcpl touches the cover, which protrudes 1.75 inches. I would have tried swapping the polarity on the tcpl but the wire colors were correct. Any ideas? After 30 years of working on these things, I'm stumped.
Thanks
Kevin

Hi Kevin - I have exactly the same problem you described, and I've done everything you and Don have discussed, with no luck. I'm desperate now and would like to know if you ever solved the problem. Most of my details are posted at https://www.hearth.com/talk/threads/classic-bay-1200-stove-shut-down-problem.198191/#post-2661119
I'll owe you big time for any info you van give me that solves this incredibly aggravating mystery.
Jenkie

Don- Pellet Stove Master (@donpelletstovemaster):
Here is what I posted in reply to your post.
Did you try bypassing the vacuum switch, they can fail when the stove heats up.
Also check the snap discs.

Hi Don - Yes and yes. Sorry for the long delay...got busy with summer things and the priority went down. I've had a number of multi-meters monitoring pretty much everything that can be monitored, plus a new thermocouple (with 30 mV traced right up to the contacts on the board), a fractional inch manometer on the vacuum system, and a new circuit board. No joy. It appears that Kevin never got back to you with a yea or nay, so i dropped him a note -- not sure he'll get it.
[sigh]