Yesterday, the new, correct nozzle was delivering a 105°C measured thermistor temperature rise above ambient (actually, the vacuum intake, which includes a bit of CO2 exhaust). It had been running for over a day, and seemed stable. We are running out of testing days. It was time to replace the higher capacity regulator with the IGT type used on the Mosquito Magnet Patriot and test that one.
After doing so, the trap wouldn’t start, twice. I said “here we go again,” attached the gas pressure NodeMCU, and tried again. This time it started right away. With an atmospheric pressure of 30.07 inHg, the IGT regulator put out almost exactly 11 inWC relative pressure. Perfect.
I noticed, however, that the temperature rise was only about 95°C at an ambient of 20°C, more or less the same as the incorrect WDA nozzle. Alarmed, I looked at the logs, and noticed that a few hours before, the temperature differential had, for the first time, dropped from 104°C to 95°C on the more expensive Marshall Excelsior regulator, which delivers less gas pressure. What was going on?
With the IGT regulator gas pressure measured, I disconnected the Schrader valve connection and turned off the NodeMCU. This time, however, there was no jump into the noisy incomplete combustion mode previously observed in these circumstances. This marks a great improvement in stability.
I don’t know what to make of this. I do know that prior to entering the rough incomplete combustion mode, the old nozzle typically exhibited an unexplained few degree temperature rise before falling down to the 55°C range. Could it be that the initial hours of the newly cleaned nozzle had a combustion mode that matched the rise before the fall in the WDA nozzle?
I do not want to investigate this now. Instead, I want to qualify the IGT regulator for use on the Mosquito Magnet. The extra long double hose doesn’t look so bad wrapped around the tank with the tank rotated 180 degrees. I hope I can recommend this device.
All this means I was probably too hard on the ill-fated Doz yant regulator that failed in the initial tests. As I said earlier, the Defender at that time was too sensitive for this world. The Dozyant regulator may work just fine in a normal trap. It does have a more attractive polished finish. But at the time, it wouldn’t work at all in the mis-configured trap. A minor negative, but one that bears some mention when discussing the Defender and its many quirks.