A/C started then stopped, thermostat went offline
I am wondering what went wrong? Any suggestion what to do next? Thanks!
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Is the unit really getting power? There may be another breaker or fuse -- sometimes in an outside disconnect near the outside unit.Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
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I am not sure. The thermostat are new (Ecobee smart) and were replaced 6 months agoJon_blaney said:Is there a good battery in the thermostat?
These are the photos of condenser unit (Carrier, 8 years old). It says no fuse I thinkJamie Hall said:Is the unit really getting power? There may be another breaker or fuse -- sometimes in an outside disconnect near the outside unit.
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Thanks! What specific things I should check on the air handler. It's a gas furnace model 58PHY070pecmsg said:The T-stat is powered from the inside unit.
Check the air handler.
https://resource.carrierenterprise.com/is/content/Watscocom/carrier_58phb070---01116_article_1428408421072_en_ss
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Follow the low voltage.0
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The fuse in the furnace control board did what it was designed to do.
Check to see all the wiring is correct, then check for shorts.
The heat works so it seems to be on the A/C circuit.
If you take the cover off the outdoor unit to check, pull the disconnect first.
Any splices between the thermostat and control board?
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SuperTech said:
Should be a 3 or 5 Amp fuse on the circuit board in the furnace. If that is blown then I would open up the electrical compartment in the outdoor unit and check for mouse nests or chewed up wires.
Thank you! I opened the air handler, the 3 amp fuse was dead so I changed to a new one. However, as soon as I turned the AC on, the fuse was blown again. What should I do next?HVACNUT said:The fuse in the furnace control board did what it was designed to do.
Check to see all the wiring is correct, then check for shorts.
The heat works so it seems to be on the A/C circuit.
If you take the cover off the outdoor unit to check, pull the disconnect first.
Any splices between the thermostat and control board?
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Some additional photos
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Thanks let me try that. To check for wiring shorting, is there a special tool for it or you just follow the wires from the air handler to the condenser unit?mattmia2 said:Move that blue and red wire where they connect to the contactor, are they chaffed? It could be the contactor but I would suspect the wiring of shorting somewhere long before the contactor.
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Pull the wires off, don't let them lay on metal of touch themself and try again. If the fuse blows tell him Hes full of $hit!tomtomtom said:
Thanks for the reminder! I called a contractor in my area and was receive a quote for about $250 to replace the potential bad contactor. Is it reasonable?pecmsg said:Do not install a larger fuse.
Might be time to call a contractor.
He should have done that to begin with!2 -
mattmia2 said:
You can learn some things with an ohmmeter or a test light but it is mostly visual inspection.
An ammeter can tell you what is going on with the contactor, if the coil is partially shorted. It could be a delay control or something like that too if there is one.STEVEusaPA said:Get a qualified tech with the skills, and/or a pro short tool. It would've already been fixed by now.
I've never just replaced a fuse and hoped it would work. If it were a board without a fuse you'd be out the price of 2 new boards.
Thank you all! Pulling the wires out then manually pushing the contactor activated the condenser unit. I am going to try replacing the contactor (HN51KB024) myself. What is you guys go-to store to buy it?pecmsg said:
Pull the wires off, don't let them lay on metal of touch themself and try again. If the fuse blows tell him Hes full of $hit!tomtomtom said:
Thanks for the reminder! I called a contractor in my area and was receive a quote for about $250 to replace the potential bad contactor. Is it reasonable?pecmsg said:Do not install a larger fuse.
Might be time to call a contractor.
He should have done that to begin with!0 -
Does the fuse blow with the wires disconnected from the contactor? Do you see the wires compromised either where they are crossing over each other or where they go through the panels of the condenser?
You can check the resistance of the coil in the contactor with an ohmmeter, it is marked as being about 40 ohms, also check that it is open to the case of the condenser.1 -
Remove the blue wire from the right side of the contactor and try turning on the A/C at the thermostat again. If the fuse doesn't blow then you have a bad contactor. I wouldn't worry about getting the exact same contactor, those particular ones are junk. Buy a Titan Pro 1.5 pole 40 Amp contactor with a 24 volt coil.1
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Update: I was able to change the contactor and got the AC work again. Thank you all for your help!0
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and what does the contactor have to do with the t-stat?0
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