We purchased a Quadrafire Mt. Vernon AE pellet stove for our family room two years ago. It operates reasonably well, but has a very unique thermostat (wall control unit, as they call it) that appears to possess at least some of the stove's logic within it. I would like to be able to bypass this thermostat and control the stove with a different thermostat, especially given that these stats appear to have some problems (and we're on our third one now, all replaced under warranty). Unfortunately, I'm not able to figure out the signalling scheme for this thing and I'm wondering if any Cocooners have ideas. I have looked everywhere online for a schematic and asked my dealer, but without success. Apparently when this fails they just replace it with a new one.
This thermostat is much different than a normal thermostat, and I am comfortable working on those. This one, though, behaves nothing like a normal stat. There are only 3 wires between the wall thermostat and the stove. One is marked "+", the other "-" and the third "C". There is 3.33 Volts DC across the pos and neg terminals, and as far as I can tell they simply simply power. I originally thought the C wire was a common, but that's not the case. Communications seems to occur on the "C" wire, but I have no idea how to measure what is being communicated. It seems to be more than a simply contact closure as the wall unit can tell you about 15 different conditions and faults depending on what is going on with the stove, and provides other info such as the level of the flame, etc. And it all appears to travel on this one, copper wire!
Any idea how to measure the signals traveling over that wire? I guess I shouldn't be surprised at this given that video can travel over a single wire, but I simply have no idea as to what to measure / try to observe. If I could figure this out perhaps I could then duplicate these signals and control the stove differently, at least for a short while if the stat goes down again. But I've never worked with any type of unit like this, and don't really know where to start. Ideas welcome, and thanks in advance.
This thermostat is much different than a normal thermostat, and I am comfortable working on those. This one, though, behaves nothing like a normal stat. There are only 3 wires between the wall thermostat and the stove. One is marked "+", the other "-" and the third "C". There is 3.33 Volts DC across the pos and neg terminals, and as far as I can tell they simply simply power. I originally thought the C wire was a common, but that's not the case. Communications seems to occur on the "C" wire, but I have no idea how to measure what is being communicated. It seems to be more than a simply contact closure as the wall unit can tell you about 15 different conditions and faults depending on what is going on with the stove, and provides other info such as the level of the flame, etc. And it all appears to travel on this one, copper wire!
Any idea how to measure the signals traveling over that wire? I guess I shouldn't be surprised at this given that video can travel over a single wire, but I simply have no idea as to what to measure / try to observe. If I could figure this out perhaps I could then duplicate these signals and control the stove differently, at least for a short while if the stat goes down again. But I've never worked with any type of unit like this, and don't really know where to start. Ideas welcome, and thanks in advance.
