In June, 2018, I was facing a new mosquito season with an old 2002 Mosquito Magnet Defender and a worse-looking Liberty. I needed a reliable trap to intercept the mosquitos on their way from the adjacent wetland to the house and yard, so I purchased a new Mosquito Magnet Liberty. Certainly, in the years since 2002, the company through its transitions and maturation, had been able to make their traps more reliable by fixing the problems that have been so often mentioned on these pages and elsewhere. I hooked it up, turned it on, and it “just worked.” Until the end of July, where it stopped with a flashing light, a fault. Tried restarting it, again a fault.
I hooked up the tire pump compressor to the Schrader valve, and the pump pressure gauge went to 140+ psi. This was way high. I let it run for a minute or so, but the pressure never fell, this must be a clogged nozzle. The Patriot disassembly videos showed that the Patriot was just an updated Defender, with a few improvements, and who knows how many cost saving measures incorporated. Anyway, one improvement is that the Patriot nozzle just fits into the metal case and is fixed with a single screw. There is no need to open the case to remove the nozzle, a great improvement!
The nozzle was also different. Instead of having a cone pattern, it has one single orifice right in the middle measuring about 0.31mm or about 12 mils. It has the removable sintered fuel filter that unscrews. I soaked them in mineral spirits for 1/2 hour, then into a carburetor cleaner (acetone and toluene) placed into the ultrasonic cleaner for 1.5 hours. The orifice was basically clean before and after, the fuel filter brightened up quite a bit, and passed air quite easily. I tested the nozzle using my test fittings and the tire pump, and the pressure read about 35-40 psi, which is very good (low). I also hooked up the tire pump to the Schrader valve again, and again, it read about 140 psi. Was the Schrader valve somehow blocked?
I re-assembled the Patriot after cleaning out all the awful detritus that had accumulated over two years. It started right away, and ran for almost a day before failing. I then replaced the propane tank, although it weighed ~20 lbs with a fresh one ~35 lbs. I remembered that this trap has been running for much longer than the Defender, which lasts 21 days, but perhaps the almost empty tank was causing problems. The Patriot ran again for two days. It had caught just 3 mosquitos.
This afternoon in the heat of the day (fewer mosquitos), I moved the trap to the patio and opened it up. I removed the thermistor assembly and the igniter. Amazingly, the nylon or plastic screw that holds the thermistor did not break, although it was severely darkened. What an improvement! The thermistor metal probe had some deposits that might cause a slight amount of thermal insulation, not good for a probe. I used a steel brush to clean that off, and measured the resistance while heating it with a hot air soldering station. It seemed ok, or at least it wasn’t broken. I watched the igniter during a start cycle, it turned red a bit, but not as much as I would have liked. The voltage across the igniter was 9.02 volts measured with a Fluke DVM, which is typical. I replaced the igniter with the last of my new ones, which lit up a bit hotter looking, although the new igniter was not suffering the deposits of the old one. Time to order more igniters, although these gadgets are not nearly as reliable as they are cracked up to be. This would be the second igniter that was not open but suffered from “not hot enough,” and this one came from the original trap.
Suspecting the regulator or valve, I removed the solenoid during startup and heard the clicking sound of the valve closing – the solenoid was working. Being too hot and lazy to remove the nozzle and check the flame there, I took the valve apart to expose the intake and exit. Opening the tank valve, I heard gas escaping. I lit the gas with a match, and there was plenty of flame, more than out of the Defender valve. The Patriot valve must constrict the flow additionally to reduce the gas flow, but it seems that trap delivers propane to the nozzle, I hope.
I started the trap, the thermistor assembly bracket got fairly hot to the touch, indicating combustion, but the trap went into an error code anyway. The case was not hot at that time, which is amazing to me. This makes me think the combustion and resulting temperature rise is marginal, or there is an under-value measurement issue like in the Defender. Evidently, there is a marginal condition there.
The trap has been running for an hour on the patio. Don’t sit outside near the trap! If it lasts the night, I will put it back where it protects the patio. Otherwise, I will have to investigate the “marginality” issues. Why is the temperature sometimes too low? Is it really too low, or is it a problem on the controller (like in the Defender)? Could it be too low because of an constriction in the combustion path, which would also cause high pressures with the tire pump test? I wish I had measured the trap when new for a base line. I can’t imagine that deposits would so completely clog the exhaust path to prevent free exhaust flow, but I have never been able to imagine the things that go wrong with these machines until discovered by myself or others. Stay tuned.