Quadrafire won't stay lit when completely cold

[Radiorat]

I'm trying to figure out a problem with my free-standing CB1200 Quadra Fire that's driving me nuts!. I've had it since '98 and it's worked flawlessly (aside from maintenance replacements like snap disc's, an igniter, etc) until the beginning of this season, when it wouldn't feed, combustion blower wouldn't change speed regardless of fan setting and so on. Anyway, went ahead and changed out the control box and then everything seemed to be just fine.

Now however, if the stove is stone cold (I use a programmable thermostat that turns it way down overnight and when I'm at work) it won't completely start up. I'll come home (or get up) to it quiet with call light lit. I reset it and it immediately feeds and lights up and cycles fine the rest of the day/night, again, until the next time it gets completely cold. I originally thought it wasn't feeding at all upon restart but this morning I caught it during it's initial start-up and here's what it does: Call light comes on, blower motor comes on and it begins to feed. Then however, only about 30-50 seconds into the feed (it seems, instead of the 98 seconds the owners manual says it should feed) it stops feeding and then the blower motor goes from it's "normal" speed down to that really low speed you get when you first plug it in. From there the few pellets in the firepot light, but it doesn't continue to feed so they eventually burn out and everything times out and it shuts down. This is the state I usually find it in when I get home.

One final clue that this may be temperature related: after I installed the new control box, everything checked out (blue flashes, blower motor normal speed) but STILL wouldn't feed. So just to see if the igniter was working, I threw a handful of pellets into the firepot and they lit. And then, as soon as there was a bit of warmth in the firebox, the auger began to feed!

Any thoughts? Perhaps the vac switch? I did check out the tube attached to the vac switch to make sure it was clear (including where it attaches to the auger area). I hate to keep throwing parts at it, but after buying 2 tons of pellets I'm motivated! Thanks!!

 

[kilbury]

I would begin with checking out the lights on the control box, green, red or yellow when off? test the themocouple. It should get 15Mv within 30 seconds or so of putting heat to the tip. You can jump out the vacuum switch to completly rule that out. Where is the feed rate slide set at? How is the length of you pellets, long? I'm really leaning towards a wore out TC on a stove of that age.

 

[Radiorat]

Thanks so much for the reply! I've tracked the lights. No yellow light from the box that I've seen at all. Upon this failed start-up sequence, it never gets up to temperature to get the green light lit so perhaps it's just not feeding enough pellets to get a big enough fire to get up to 200 degrees (green light)?

I've ordered a new TC - you're right in that it's been 12 years! I increased the feed rate as well (and the pellet length isn't abnormally long). I also see with this new control box I have the option of putting it on "setting 2", which increases the feed rate by 10%. That's something I may do if everything else fails.

If this was a consistent problem it would certainly be easier to troubleshoot! I'm thinking though, that this only happens when the stove is completely cold because, after I get that initial burn cycle complete, there's enough residual heat left in the firebox for subsequent cycles to get that green light lit and continue to feed pellets.

Thanks again for your help! It's most appreciated!!

 

[Radiorat]

Well, after I posted last, the stove started working just fine! But then a few weeks later, nothing. Obviously an intermittent thing going on. So, installed the new TC and still no fuel feed. Jumped out the vacuum switch (now, by "jumping out" you mean just unplugging and then taking a wire to connect the two leads, right?) Assuming I did that correctly still can't get the auger to feed. If I load the bowl by hand, I get ignition, green light, red light, convection blower..then the pellets are all gone. I've put a multimeter on the connection that goes to the feed motor and get nothing.

So far then, I've replaced the control box, snap disk #2, and TC. Again, assuming I jumped out the vacuum switch correctly the only remaining culprits would be the feed motor (but again, can't get any indication that it's getting power) or the wiring harness.

I've also checked all wiring connections (more than once). Please give me an idea I haven't thought of yet!

 

[tjnamtiw]

I don't have the 1200, so it may have some special surprises but my Castile often does what you describe during the night. I AM suffering through 2 tons of these Gawd Awful Carolina Wood Pellets that have lengths over 3" that bridge the top of the chute and limit the amount of pellets that get into the pot. Also, if I have the feed gate shut down too much, they don't feed very well and give me the problem you describe. I know you said you don't have overly long pellets but I would try opening the feed gate all the way and see if it fires off well. Use the Medium setting if you are uncomfortable with a super big flame. At least it should still start up fine. At least you will eliminate that possiblity.
I did infer from your post that you might have just gotten two tons of possibly new or different pellets. You've had the stove for a loooong time so I'm sure you know you can't count on the feed rate adjustment always being the same.
You don't by any chance clean your stove just before going to bed do you? That's something I've noticed with both my stoves > If I don't throw a small handful of pellets into the hopper for the first startup after cleaning, it will missfire. I don't know if my scraping the pot and banging the trap door open and closed causes the pellets to fall back down the auger so that the initial charge of pellets is too small. These things have a mind of their own.
You DID jumper the vacuum switch correctly as long as your jumper wire isn't shorting out to the chassis. Because everything works fine if you give it the initial boost of extra pellets, it sure sounds like everything is working except the initial run time of the auger. My time is 60 seconds on my stoves but the 1200 might be different.

 

[kilbury]

You may want to try powering the feed motor directly, by applying power to the white and either red or black wire. This will tell you if the feed motor is bad. Also you should have the capacitor in line with the feed motor connection. This will keep it from feeding backwards.

 

[Czech]

Have you made sure the thermocouple is made up all the way into the ceramic cover on the burn pot? Sounds like it is not sensing up to temp prior to going into run mode, and therefore shutting down.

 

[Bkins]

I have had the same thing happen with my Mt Vernon. I have foound it to be the pellets. Try some different pellets and see what happens. Some pellets lite easier and throw off more heat earlier then others. This problem your having will just drive you nuts. Ask me how I know.

David