Castile Thermocouple

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Czech

Minister of Fire
Hearth Supporter
Jan 20, 2006
1,076
Twin Cities, MN
It’s a blast from the past, oh my it’s been a awhile, don’t roast me too bad! Anyway, I’m stumped, and I never get stumped damn it. So I’ve got an older FS Castile (2005), one of three stoves in the house, it’s the workhorse and I swear I could take it apart and put it back together again blind folded. I had a bad thermocouple, my fault, snapped a wire replacing the pot gasket. No big deal, right? So I got a new TC, manually check it before and after install, voltage ramps up with heat applied, all good. Came with that new ground wire deal, installed that on the red leg per instructions. So fired the stove up and no green light, cycles through start up but never goes green and shuts down. Huh. I wondered about the board, the one that is in there is not good, apparently an ignition issue fried that circuit and I was manually lighting for a while. So I thought I’d finally get a new board, and I order a new TC too, just because its freaking cold out and I can always use the spare parts in the shop. So new board and new TC get installed (again tested the TC, all good), start her up, no green light. Removed the new ground just because, no go. Checked continuity from TC to legs 1 and 3 at box connection, all good, voltage good also, can see it ramp up from 0 (cold) to 40 mV or so (hot). Checked all grounds, tightened everything, made sure scratch connections at box were patent. No green. Is it possible the new board is goofy ya think? Any other thoughts? Thanks!
 
Are you sure the tc is touching the inside end of the cover, and is sticking in pot at least 3/4"? Is the tc an OEM part, not aftermarket? Did you unplug stove before removing and installing control box, so as not to run the risk of toasting it? Do you know someone with another Quad stove you can test your box in? Try unplugging stove and reseating control box? kap
 
Hey Kap, long time! So TC is OEM, I bought two just because. Yes to the TC touching inside cap, and being fully extended into pot. I can see increasing mV both at the ends of the TC, and at legs 1 and 3 at the control box socket. I also tested the box on another Castile last night, and it operated normally, call light, blue board setting light, eventual green board light, then red board light at full temp. So the board is good as far as that goes. Because of this I started chasing grounds last night, reseated every one I could find, refreshed all connections. I also spent some time with the scratch connections at the board socket, those all look ok. One odd thing to note, I did carefully disconnect the TC (red leg) while the stove was running, oddly enough the red board light came on and the auger cycled a couple times as if the box was finally happy. After two short cycles of the auger, the amber board light started flashing three times as it does with bad TCs. Man I hate electrical gremlins, I’m really staring to think this is a ground issue because the box seems good and the board is seeing the TC apparently.
Are you sure the tc is touching the inside end of the cover, and is sticking in pot at least 3/4"? Is the tc an OEM part, not aftermarket? Did you unplug stove before removing and installing control box, so as not to run the risk of toasting it? Do you know someone with another Quad stove you can test your box in? Try unplugging stove and reseating control box? kap
 
Have you checked your ground on your power coming into the unit? Check the ohms between the neutral and ground on your power. It should be almost zero ohms. Maybe you have a poor ground connection to the stove.
 
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Also check the jumper plug, the molex pins do tend to oxidize, may not be making a good connection. The card edge connector (control box plg) try cleaning it with some deoxit or another contact cleaner. TC connects on pin 1 and B. Are the wires for the TC on the correct terminals.
 
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Also check the jumper plug, the molex pins do tend to oxidize, may not be making a good connection. The card edge connector (control box plg) try cleaning it with some deoxit or another contact cleaner. TC connects on pin 1 and B. Are the wires for the TC on the correct terminals.
All great advice, I had yet to check the jumper, thanks. After another few hours of playing with this thing, I remain stumped, I broke down and clicked on a new wire harness. I’m thinking the card slot connections are not good, it looks like some are bent in half and misaligned, rather than refresh or risk a board, the harness may be a best long term solution. I thought about soldering a new 2x15 socket into the existing harness, but thought twice. I’ll reply back with results, if this does not work you guys will have to talk me off the ledge!
 
Have you checked your ground on your power coming into the unit? Check the ohms between the neutral and ground on your power. It should be almost zero ohms. Maybe you have a poor ground connection to the stove.
This comment made me check a power strip that I had not thought of yet, it tested good but could have very easily been part of this problem. I was very focused on other areas, thank you for this reminder to take a step back.
 
Ok gang, I’m thinking about taking up drinking again, unlike repairing this stove I was really good at that. Anyways, installed new wire harness thinking the control board socket was bad, the scratch connections were pretty shot so I thought oh well, whilst I’m at it. That job actually went pretty darn well, gave me a chance to really clean the insides without all the clutter in there. Stove started up like a champ, but once again never got the green board light on, nor the red board even when nice and roaring with a full pot of pellets. Once again, two of two new TCs test fine, as do pins 1and 3 at board socket, all ramp up millivolt wise when heat is applied to tip of TC. I still think it is weird that when I disconnect a leg of the TC when the stove is running, the red board light comes on for a few seconds and the auger cycles a couple times, enough to get me excited. Then it fails with the amber three flashes from the board light that are normal with a broken TC. Wtf am I missing gang? The stove serial is 007 1188442 FS Castile if that helps. Does it matter that the old TC was stripped farther back? See pic.
 

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Czeck if you can take the pcb out of the box. Check all the solder joints for cracks/cold solder joints. Bad or burned traces.

left is a good joint right is cold solder joint
[Hearth.com] Castile Thermocouple
 
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Another great idea and super advice, fixed many a board reflowing solder. In fact everyone should own a decent iron and a lighted magnifier! Sadly, this super idea was addressed, and I found no bad connections in this case. Now you want to know the fix? Did I tell you guys I have it running? Omg see below...
 
So here’s the deal, huge kudos to the pellet head guys in WI, you know who you are, I own you a 16 gallon keg of beer. I had done everything possible to address this issue, and I typically never give up, I’m obsessive about these things, some say neurotic. And I was bested. I did get the stove going, but it wasn’t pretty, I’m embarrassed to even tell you guys how. But I will. I hacked the tip off a new TC and spliced it to the old wires, and it worked. Honestly. Then because the twisted connections were impacted by the heat in the fire box, I stuck that sucker in one of the pot holes to protect the connections by keeping them in the ash drawer. Worst hack job ever, but it worked. No real answer why, still kept me up at night, but I had heat. And then some guy mentioned above checks with his techs, and one says “did he try reversing the connection on the TC?”. Like why would that matter, right? Really? And it’s not really easy to do, these are male and female one way bullet connectors, red to red, yellow to yellow, gotta cut and rewire, new TC and new harness, no way I’m cutting those. So I styled up a couple adapter wires, flip flopped red to yellow and yellow to red, and the damn thing worked like a charm. Are you kidding me? Anyway, ended up making things more pretty and permanent and buttoned it up, stove is running like a champ. For the record, these are OEM parts, only connectable one way on the harness, new OEM box too. Now someone with a PhD in electronics explain this to me please!
 
You are not the only one that has run into this issue. Most have bad results with after market, and some with OEM, and others with what are suppose to be OEM parts, but are not. It is getting to be a buyer beware world out there for stove parts. kap
 
Yes your actually the 4th or 5th this season that has had the same issue.
 
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It’s crazy because it absolutely does not make sense. I’m mean it’s not like these these are polar, right? Yeah I know the wires are colored and whatnot, but the electrical scheme should work either way from what I understand. And I’d never think to start cutting up brand new OEM HHT labeled boards and parts and harnesses just to try reversing wires to troubleshoot, this one has me puzzled. Thanks guys for all your help, I’ll put this one in the “hey have you tried” file.
 
Hey one more thing, this was three different new TCs, three boxes (two new, different stoves), and a new and old harness. These parts worked on other stoves, just not mine. I guess that’s what has me puzzled, this is specific to my stove. My stove with the new parts. That work on other stoves. Huh. At least it’s warm in here! Thanks again.
 
Well thermocouples are a little different than thermisters. Thermisters relay a restistance which is calibrated to a temperature. Thermocouples create voltage (millivolts) and they are polarized. The correct connection it sends pos voltage to be calibrated as temp. If reversed it send neg voltage which the controls can’t decifer, so it fails
 
Yep, so along these lines, why did the parts (3TCs and new board) work as is in another stove? Could this be some sort of grounding or polarity issue specific to my stove? That’s what has me super puzzled.
 
Depending on the age of the stove but I would suspect it be a ground issue. They have changed the boards and components on the boards so much over the years, without reverse engineering each board or having the changes listed in their revisions hard so say for sure.
 
I have at Castile freestanding stove that I fried the board on. Before the board was fried it would occasionally not start up in the morning. Red call light would be on, I would hit the reset and it would run great. This only occasionally happened, stove is a 2007. I put the new board in added the ground for the thermacouple that it came with. The stove ran great for about two days and then wouldn't come on when heat was called for. I mean just about every time we would have to hit the reset button. It was driving me nuts because it always ran good, the only thing different was the board and the new ground. I pulled the new ground off and the stove has ran like new for the last week. Didn't have to hit the reset once.

Bob