Checking if float switch is open, what low-voltage should be at condenser?


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Old 05-19-21, 01:46 PM
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Checking if float switch is open, what low-voltage should be at condenser?

I just tried to turn my central air system on for the first time this season and the fan kicked on, but the condenser did not... (Like I seemingly post every year) I really don't want to go up into my crawl space, fiberglass-insulation filled 1000 degree-attic to check the float switch. (Because unless it got disturbed somehow it shouldn't be a problem, the system worked at the end of last season).

IIRC the float switch breaks the Y-wire on the evaporator, which I think is the wire that runs out to the condenser, yes? So I should be able to check for voltage on the low-voltage wiring outside at the condenser to confirm if the float switch is open or closed (when the thermostat is in cooling mode)? What sort of voltages should I be seeing? (And this is aside from checking for other normal voltages/issues in the condenser panel.)

Thank you
 
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Old 05-19-21, 01:55 PM
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During a call for cooling there should be 24vAC between the two wires to the condenser.
Check directly at the wiring from the house to the condenser.
Don't forget to allow 5 minutes after calling for cooling for the delay to pass.
 
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Old 05-19-21, 04:59 PM
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Perfect, thank you. Really hoping it's something outside and not in the attic 🤞
 
 

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