Bob wrote:I'm not so sure the design is defective.
First the AA uses the same design--a temperature probe to sense ash temperature-- for control of ashing and neither you nor anyone else so far as I know say the AA design is defective. I simply don't see how the use of more modern temperature sensors and control could be considered a defective design.
If you look at the measurement characteristics of the A-A temperature sensor and the AHS thermocouple, there is a world of difference. The A-A sensor is basically a bi-metal snap switch-like sensor. It integrates temperature changes and has a slow to respond characteristic. A thermocouple, on the other hand, is a tiny sensor, and does not integrate temperatures at all. It's response to change is instant. The electronics amplifies the milli-volt thermocouple voltages to something useful, also includes a hysteresis function, which allows a similar integration-like capability. But it's really different and in my opinion not what's needed. As has been pointed out many times none of us has the engineering data for a definitive answer. I still stand by my opinion, that it's not the right design.
I welcome an design explanation of either the A-A or AHS system by anyone. Temperature design set points, for rising and falling temperatures, hysteresis values, CO concentrations that cause or do not cause puff backs. Even if you don't have numbers, just explain how it's supposed to work. Is the idle draft what is expected to clear out the CO boom-boom mix? Etc.