Three days after replacing the nozzle and igniter, a previously noticed anomaly has reappeared. In this case, the combustion temperature measurement dropped from 125°C to about 85°C for no apparent reason, just like before. Regrettably, the MQTT link had gone down (I use a free MQTT service that has frequent service interruptions), and I missed the decline. The unit did not reboot, and was still in the “running” state, since 85°C is within the range of permissible temperatures.
I issued the command to start a new cycle, and the system skipped the customary cool down, and just turned on the igniter with the fan on low and the gas off for 15 seconds. This time, after about 90 seconds, the temperature started to increase. After 10 minutes, it was back to 125°C. But then, a few minutes later, it rose to 129°C with a case temperature of “only” 53°C, and then started to fall. Now, after 20 minutes, the temperature is back to ~86°C. Turning on the igniter for 120 seconds failed to increase the temperature. Then issuing the new cycle command sent the temperature back upward. Later on this evening, the trap started with no problem and has been running overnight…
The nozzle and igniter are both new. I don’t think I should use the tire pump, which has worked in the past. So what’s left? I didn’t check inside the combustion chamber for deposits that could obstruct the gas flow. The propane regulator is original and has not been replaced. I can get a new one and see if it makes any difference. The basket and case are on tightly. The basket has only about 50-70 mosquitos over 2 days (but no one is getting bitten, either). Could it be an intermittent in the temperature measurement circuit, and not the temperature itself? I will look into this tomorrow during the day. It is kind of exciting to be zeroing in on a misbehavior that has been bugging me for quite some time. Please wish me luck.