Troubleshooting - No Power To AC Unit - HVAC - DIY Chatroom Home Improvement Forum
Advertisement


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread
Display Modes
Old 05-25-2020, 09:22 AM   #1
Member
 
Join Date: Jan 2017
Posts: 158
Rewards Points: 210
Default

Troubleshooting - no power to AC unit


I've tried booting up my AC unit for the first time this spring and it's not turning on.

The furnace fan turns on but the AC doesnt budge. I checked the obvious things and all looks good - thermostat appears to be wired correctly, the drain line is not clogged, fan isnt seized, breaker isn't tripped.

I used a voltage tester and there doesnt seem to be any power feeding the unit. However, the thermostat wire seems to set off my tester so it has power running through it.

Any idea on what could be the problem??
PatFlemming is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 05-25-2020, 09:25 AM   #2
Member
 
Join Date: Nov 2014
Posts: 5,855
Rewards Points: 758
Default

Re: Troubleshooting - no power to AC unit


So you have a call for cooling, the contactor is pulled in but you don’t have line voltage feeding the unit?
The condenser will be off a separate power feed then the furnace. It’ll be a double pole breaker.
roughneck is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 05-25-2020, 09:35 AM   #3
Member
 
Join Date: Jan 2017
Posts: 158
Rewards Points: 210
Default

Re: Troubleshooting - no power to AC unit


Quote:
Originally Posted by roughneck View Post
So you have a call for cooling, the contactor is pulled in but you donít have line voltage feeding the unit?
The condenser will be off a separate power feed then the furnace. Itíll be a double pole breaker.
I have a double pole breaker labelled "AC" which I turn off in the fall. I turned it back on this spring like I always do. I tired resetting it a few times also.
PatFlemming is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 05-25-2020, 09:39 AM   #4
Member
 
Join Date: Nov 2014
Posts: 5,855
Rewards Points: 758
Default

Re: Troubleshooting - no power to AC unit


Do you have power at the disconnect switch for the condenser?
Is the disconnect fused or non-fused?
You’ll have to backtrack from the condenser using your meter.
roughneck is offline   Reply With Quote
Old 05-25-2020, 11:29 AM   #5
Member
 
Join Date: Jan 2017
Posts: 158
Rewards Points: 210
Default

Re: Troubleshooting - no power to AC unit


So, i ran a few more tests. I had someone call for AC at the thermostat while I was at the unit with the panel removed. I heard a click and then a humming noise but the AC didnt turn on. Also, the capcitor looks corroded. not sure if this has anuthing to do with it. Stangely, still no reading from my voltage tester on the 240V.
Attached Thumbnails
Troubleshooting - no power to AC unit-ac2.jpg  
PatFlemming is offline   Reply With Quote
Old 05-25-2020, 11:34 AM   #6
Member
 
Join Date: Nov 2014
Posts: 5,855
Rewards Points: 758
Default

Re: Troubleshooting - no power to AC unit


As I said before, your furnace has power but the condenser circuit doesn’t. Capacitor has nothing to do with the issue. Your contactor is working normally as it gets control voltage from a separate source.
You need to find where your losing voltage. Disconnect, fuses, breaker, wiring.
roughneck is offline   Reply With Quote
Old 05-25-2020, 04:36 PM   #7
dj3
Member
 
Join Date: Apr 2020
Location: CA
Posts: 1,569
Rewards Points: 296
Default

Re: Troubleshooting - no power to AC unit


If you have a disconnect near the condenser, replace the fuses (with the same exact kind).
Then make sure the bar is positioned the right way.
dj3 is offline   Reply With Quote
Old 05-25-2020, 04:49 PM   #8
Member
 
Join Date: Nov 2014
Posts: 5,855
Rewards Points: 758
Default

Re: Troubleshooting - no power to AC unit


Quote:
Originally Posted by dj3 View Post
If you have a disconnect near the condenser, replace the fuses (with the same exact kind).
Then make sure the bar is positioned the right way.
No reason to replace the fuses, when they can be easily tested. If the OP has them in the first place.
And if the OP were to replace them and they blew right away, heíd be back to square 1 with no diagnosis.
roughneck is offline   Reply With Quote
Old 05-25-2020, 05:16 PM   #9
dj3
Member
 
Join Date: Apr 2020
Location: CA
Posts: 1,569
Rewards Points: 296
Default

Re: Troubleshooting - no power to AC unit


You're right.
dj3 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Top of Page | View New Posts