Problem with new Quadfire Castille control box

I installed a new ('clear') control box 2 months ago on my 5 year old Quadrafire Castille pellet stove (the old box 'died'; confirmed by the dealer/tech). Something bad is happening with the new one now. When it powers up, it flashes the blue light 4 times,for about a minute (which is good - indication of setting for Castille model). But it also starts flashing a yellow light 3 times, continuously forever. The blower comes on immediately, and stays on (for over a 1/2 hour now). But no pellets feed.
Any ideas? Thanks.

Thanks for the info. I pulled off the porcelain cover, and checked the thermocouple. I don't see any obvious breaks. However, the insulation around the wire (both under the porcelain cover, and beyond) has become brittle, and pieces of the insulation have worn off. I tried to fire it up a few more times, and the amber light did not come on. I've now seen 4 different symptoms: 1. blower comes on, blue light flashes for a minute, and when the igniter should come on, the GFCI outlet the stove is plugged into trips. 2. fire ignites, but goes immediately out. 3. no ignition, no tripping of the GFCI outlet, blower just stays on, no amber light. 4. same as 3, but amber light flashes 3 times, continuously. The reset button does cause the auger to drop a few more pellets, but no ignition. Since I had a spare igniter, I changed that, but it didn't make a difference. I also vaccumed & cleaned everthing pretty thoroughly (including the hopper), to no avail.

Thanks again.

Thanks. I'm going to pick up a new Thermocouple on Sat., and will post the results.

I removed the old thermocouple, and could then see that it was indeed broken. I got a new one ($49 including tax), and installed
it, and so far everything is working fine! Once I got the new one, I could see how much of the wire insulation around the old one
had deteriorated and broken off. I'm hoping that was causing the tripping of the GFCI outlet (ie. bare wire coming in contact with
something like the bracket that holds the thermocouple on the firepot). Thanks very much for your help jtp10181