# Quick question about home HVAC

**URL:** <https://boards.straightdope.com/t/quick-question-about-home-hvac/630392>\
**Category:** Miscellaneous and Personal Stuff I Must Share\
**Created:** [August 4, 2012, 4:47am UTC](https://boards.straightdope.com/t/quick-question-about-home-hvac/630392 "2012-08-04T04:47:49Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![diku](https://avatars.discourse-cdn.com/v4/letter/d/4af34b/32.png) [@diku](https://boards.straightdope.com/u/diku)\
**Post date:** [August 4, 2012, 4:47am UTC](https://boards.straightdope.com/t/quick-question-about-home-hvac/630392/1 "2012-08-04T04:47:49Z")

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So I’m calling a tech in the morning, but just wanted to run this by the folks here first.

Tonight while the A/C was running, power tripped to the entire house, and quickly came back on. The A/C kept running when power came back on for a few minutes, then shut off. Now, it won’t come back up. I checked all the breakers and they look ok. Funny thing is, nothing will work. The furnace doesn’t kick on, and turning on the fan blower doesn’t work either. Just as a quick test, I cut the power and wired the r and y terminals together, powered up, still nothing.

I’d like to think this is just a bad thermostat, but when I wired the terminals together, that should’ve bypassed it. Any quick ideas? Like I said, I’m calling a tech in the morning, but I’m just looking for some ideas of stuff to think about.

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**Author:** ![The\_Vorlon](https://avatars.discourse-cdn.com/v4/letter/t/d07c76/32.png) [@The\_Vorlon](https://boards.straightdope.com/u/The_Vorlon)\
**Post date:** [August 4, 2012, 6:11pm UTC](https://boards.straightdope.com/t/quick-question-about-home-hvac/630392/2 "2012-08-04T18:11:54Z")

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Sounds like a capacitor failed—should be a easy fix

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**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\
**Post date:** [August 4, 2012, 6:30pm UTC](https://boards.straightdope.com/t/quick-question-about-home-hvac/630392/3 "2012-08-04T18:30:23Z")

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Do you have a meter?  
Check the power to the thermostat - if you don’t have 24VAC, ain’t nothing gonna work…

BTW - it’s not a capacitor (at least not a motor-start capacitor). A single capacitor failure wouldn’t affect both the compressor and the blower.

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**Author:** ![diku](https://avatars.discourse-cdn.com/v4/letter/d/4af34b/32.png) [@diku](https://boards.straightdope.com/u/diku)\
**Post date:** [August 4, 2012, 7:13pm UTC](https://boards.straightdope.com/t/quick-question-about-home-hvac/630392/4 "2012-08-04T19:13:21Z")

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Turns out it was a blown fuse. 15 minute fix.

Thanks for the replies!