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Thanks again Marc. Do appreciate the offer. Bought an extra one to have on hand as well.

FYI in case anyone else experiences this, only happened one more time. Then began issue with condenser continuing to run after setpoint reached, with indoor shutting off properly. Tapped contactor and it shut off each time. Replaced contacter and no more issues, so we'll see. Thanks again for the input.

Thanks Marc. Coils have already been cleaned. The contactor mechanism itself is enclosed, I was referring to the wire attachment terminals since they are not and do have some corrosion. I have another thermostat from when I replaced it several years ago I keep as a backup. So far it's been normal the past several days so waiting out this heat wave a couple more days then doing some more checking. Thanks again.

I did not remove power. So far hasn't messed up again. On another board someone said it was likely high/low pressure switches. Found another guy that had near the exact same thing and he said his was the contactor having corrosion and carbon buildup from arcing while engaging and caused intermittent contact issues and replacing that fixed his. Either of these sound possible causes to you? At least the contactor is easy and cheap. May even start with cleaning connections and applying dielectric grease if that is a possibility. Thanks again. Kevin

Just to clarify, when this occurs, outdoor unit shuts down when temp is reached as it should, however indoor fan does not (in Auto), "Cool On" stays on on thermostat and outdoor unit won't start again when temp inside rises unless turning system off at thermostat and turning back on, then will operate normally (i.e. outdoor and indoor shut off and "Cool On" shuts off when temp reached) until the next mess up. Thanks, Kevin

Thanks Marc, but that's not the case here. "Cool On" normally does not stay on on mine when the condenser isn't running and it's in Auto. When it does this, it can get to any temp in the house while set on 70 and it won't kick on to cool it down (highest while I was gone was 78). Even got the thermostat to think it was 85 inside today while set on 70 and it wouldn't kick the compressor back on. Have to shut it off, then turn back on to get it running again. Thanks again.

Hi all, Our AC has started the following intermittent issue: When temp is reached, the condenser shuts off as it should, but the indoor fan continues to run and says "Cool On" like it is still running and having a call for AC. The unit then has to be manually shut off and back on at the thermostat. Then the normal lockout seems to be working properly flashing "Cool On" will until time threshold is met, then it will operate normally. Again, only intermittent, but trying to chase down what contact or sensor could cause this. I've seen posts where others replaced their thermostat with no change, so didn't want to start with that if that's not it. Thanks, hope all are well! Kevin

Thanks alot for all the replies. Helped a lot to narrow it down. Kevin

Looking into replacing our 20+ year old HVAC, even though it's going strong. Figure it's time to increase efficiency on my terms before of a failure. Looking for opinions on different brands. Split system, 3.5 Ton with gas furnace. Is there much difference in brands anymore these days? Thanks for any input. Kevin

Put in a tankless and sell the old 40. Still wouldn't trade mine after 6 years it's been in

I can attest to the much faster burn times nowadays. Much of the issue is the shear amount of "stuff" people have and it's all synthetics, which lead to the much higher heat. The other issue we have is the engineered structural components (I-joists, light weight trusses, etc.) that also burn through much faster and bring houses down much quicker. Add in improper modifications to them and it's impressive to see how fast they drop. We keep trying to change tactics to keep up and improve outcomes, but it's always a challenge. If anyone's bored and wants to look into some of the research, look up UL/NIST Modern Fire Behavior studies that were done. Really is impressive the amount of heat. http://www.firerescue1.com/Firefighter- ... -dynamics/

My 40 year old house had one I just tore out during remodel, it was unventilated and had no signs of moisture issues inside. Can't personally think of why it would react any different then any of the other walls. Not sure if that helps, but that's my experience with mine. I'd see them quite frequently when I was inspecting and never gave it a thought, not that that means anything.

The Rheem customer service is phenomenal, at least for the tankless anyway. I would assume it's good for tank also.

Thanks guys for all the input

Thanks, if I can't sweat or get wrenches in for compression, might spring for these. Haven't been able to find much about failures with them, didn't know if anyone else has. Have heard even less about compression failing.