"They hit 120 degrees a couple weeks ago. She has 2 AC's and said they didn't shut off all day." "Run-time varies from 30+ mins during heat of the day to 10-ish mins in early morn hrs" This varying equipment behavior is to be expected, isn't it? I would believe that a lot of people "set it and forget it" at their thermostat. I do. 73F from May to September, no setbacks programmed. With this in mind, how can one expect their system to do anything else but have cycle times of very different lengths? When does the thread topic change from "it's short cycling!" to "it runs 24/7!"? After all, isn't the purpose of HVAC to provide comfort? I'm comfortable at 73F. If I were to have a bigger droop set in the stat, or agree to raise or lower the set point as outside conditions change, I guess I would have uniform, perfectly long cycles. No thanks, I'll leave it as is. Comfort does come at a price sometimes.

just use one timer to run both cloners ;)

Haha, well now this makes sense. I'm in Silicon Valley and have more than enough exposure to engineers and tech types who think they can understand and improve just about anything with homespun whizbang. They far too often fail but have trouble admitting that. Usually the damage isn't too costly. That may not be so here. JoeQ, your clever "system" may bring your furnace to a premature end of life. Or may have already. And that can lead to carbon monoxide emissions in your home. Or may have already. A new furnace may be a few thousand dollars. Health damage from carbon monoxide, hard to quantify. Your "system" isn't performing its most basic requirement, which is to properly control the furnace without damaging it or risking your health. Declare your experiment over and call an HVAC company to get your stuff working right, the traditional way. Good luck.

I hadn't give thought that you might think I was infering dishonest about cleanleness until A Air commented on taking people at their word. Truth is I've lost count of how many times contractors and employees told me a coil was clean when it wasn't. Their warn't lying,they simply didn't see dirt until I showed them how to make certain. I did the same until wiser men showed me different. I still haven't mastered how to perdict what third parties ( mfgr,dealer and distributor in this case) will do. Hopfully you don't need to go that far so let's do what we can on our own before finding out. I just believe this is well worth persuing since it cost's nothing and will do no harm. I can't say the same about tapping into sealed systems. Manys a perfectly charged system has been contaminated,caused to begin leaking or worse when needlessly opened up. As a rule of thumb,as compressors get smaller, sensitivity increases across the board and skill to deal with it become's increasingly neccessary. If not useful on this unit,I have some tips for confined coils. Adapt as the need arises. I carried mirrors including one similar to those dentists and hygeniests use. It's sometimes amazing to see what's around corners. Much quicker than dissassembly only to find everything ok. A garden sprayer will handle most coil wash jobs but in addition I carried pressurized containers with different coil washes inside. I often prefer pushing dirt back out in direction it came from. A 1/8" soft copper pipe with spray head can be snaked into back side of coil and using high pressure liquid or plain air ( depending on whether pressure tank is upright or inverted) can drive dirt out to side I can see. Eventhough you can't see wand and spray head,the spray can be directed by watching dirt come out side which is visiable. I figure this can save tech time and do better work when dealing with M-splits. If a wet vac hose with 90* floor tool can be manipulated to catch dirt and liquid as it's expelled,you can do 1st class on central system coils. Bigger spray head,more water and more pressure. I would use no rinse evap coil cleaner on this ms but it usually only come's in gallons. I have no objection to diswashing or laundry detergent if that's all one has. If you have a digital thermometer that reacts within secounds of temp change, and an amp meter,do this. Watch and record running temp and amps. Do amps increase above rated run amps before compressor cut's off, do temps progressivly change as amps change and other readings. Since I've lead us this deep,I should at least say why I think this could be air flow related. A freeze up caused by low refrigerant can be expected to start iceing at point where it enter's coil then progress until air flow begin's to drop then continue progressivly covering coil in turn progressivly restricting air flow. That's a clean coil with inadiquate refrigerant. A properly charged coil drop's temp rather even across whole coil. A properly (and to a degree, inadiquate) charged coil with inadiquate air flow from dirt restriction or too low fan can be expected to frost then shortly ice across intire coil surface. Anywho,this will be one less thing tech need's to do if one must be called. Your amp-temp chart might also prove helpful.