A fly [hornet] in the ointment

One day I happened to notice the AC was on,according to the thermostat, but not blowing cold air. The condenser outside wasn’t on. The HVAC control panel said it was calling for cooling. Not good. I replaced the capacitor a couple years ago. Did some basic troubleshooting and the most likely issue was the AC contactor. Thanks to Sense I was able to go back and see how often this was happening and monitor. It was happening very infrequently but I ordered a new contactor anyways since it was $15. Replaced the contactor and did an autopsy on the old one. Since the AC is seasonal here it appears hornets built a nest inside the contactor before cooling was needed and got a very unpleasant surprise when the AC started up for the first time. I speculate that as the AC was used the fried hornets would shift and occasionally prevent contact, this resulted in the condition where the AC condenser wouldn’t start. Once again Sense proves to be an invaluable troubleshooting tool


For the @sense team. I looked back at past starts vs starts after installing the new contactor and I couldn’t see anything that could have indicated a pending failure, but maybe you can- the new contactor was installed around 10:30am EDT on 7/20/2020, the first AC run with the new contactor was 7/20/2020 10:41am EDT. You have permission to use my data.

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Thanks @powens001 - I’ll let you know if we see anything on our end :slight_smile: