Ask Experts Questions for FREE Help !
Ask

a/c unit outside wont turn on byitself, thermastat?

Asked Sep 12, 2005, 04:20 PM — 6 Answers
My family went on a trip to see relatives in the country. When we came back the a/c had quit. The inside blower motor works, just the outside unit will not turn on. Everything is fairly new, except for the thermastat on the wall, which is one of those old round mercury like switches.

I took the cover off the outside unit to inspect the capacitors, and connections. Everything looked fine. Niether compressor nor fan will turn on by itself. I pushed on the dual pole contactor and the unit jumps to life and will cool the house, I just refuse to hold it all night .

What do I need to replace to make the unit turn on by itself?

Thanks, Andrew

6 Answers
labman's Avatar
labman Posts: 10,673, Reputation: 3050
Über Member
 
#2

Sep 12, 2005, 08:28 PM
If the furnace blower is coming on, power is making it from the thermostat back to the furnace. You should have a pair of wires running from the why and B or C terminals at the furnace out to the contactor. If they have 24 volts outside, the contactor is bad. If not, check the wires between it and the furnace.
Helpful
zoom's Avatar
zoom Posts: 2, Reputation: 1
New Member
 
#3

Sep 14, 2005, 10:45 AM
Thanks for the help. Appearently there was only 24v + going to the contactor. I just took the - and screwed it to the unit housing, and it works fine now. I also went ahead and installed a new digital thermastat since the round one aggravates me...


Thanks for the help.

Andrew..
Helpful
teeball's Avatar
teeball Posts: 3, Reputation: 10
New Member
 
#4

Jun 1, 2010, 02:16 PM
The themostate will not turn the outside ac unit on but I can manuel start it at the unit
Helpful
teeball's Avatar
teeball Posts: 3, Reputation: 10
New Member
 
#5

Jun 1, 2010, 02:20 PM
[ the themostate will not turn the outside ac unit on I can start it buy pushing the contactor on the unit out side
Helpful
teeball's Avatar
teeball Posts: 3, Reputation: 10
New Member
 
#6

Jun 1, 2010, 02:23 PM
Quote:
Originally Posted by teeball View Post
[ the themostate will not turn the outside ac unit on I can start it buy pushing the contactor on the unit out side
what should I look for
Helpful
Joshdta's Avatar
Joshdta Posts: 2,453, Reputation: 230
Ultra Member
 
#7

Jun 1, 2010, 06:09 PM
Did you put a jumper from rh to rc?
Helpful

Not your question? Ask your question View similar questions

 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Add your answer here.

Remove Text Formatting

Undo
Redo
 
Decrease Size
Increase Size
Bold
Italic
Underline
Align Left
Align Center
Align Right
Ordered List
Unordered List
Decrease Indent
Increase Indent
Insert Email Link
Wrap [QUOTE] tags around selected text
Wrap [CODE] tags around selected text
Wrap [HTML] tags around selected text
Wrap [PHP] tags around selected text
Wrap [YOUTUBE] tags around selected text
Notification Type:



Check out some similar questions!

Fan blade on my unit won't turn [ 8 Answers ]

My fan blade on my central unit won't turn. It appears it is trying to turn, so I helped it with a screw driver. The fan blade then runs with out fail, but will not cool. I was told that it might be my capacitor? Why is it when the blade turns it won't blow cold air?

Installing thermastat [ 2 Answers ]

Hi. I'm trying to install a programmable thermastat and the directions say to mark the wires before taking them off of the old one. They are not marked at all anywhere. I have a red and a white one. Any idea what I should mark them as? Any help would be so appreciated. The electrition I called...

Flywheel won't turn [ 27 Answers ]

Ok, Yardman is several years old (i believe about about ten years or so) but I have had it a few months. Worked fine for awhile. Last few times I would cut it would cut for a good while then it would just cut off. Battery is weak so I would always have to jump it off beforehand. No problem with...

Air handling unit won't turn off. [ 13 Answers ]

Hi, I have moved into new offices and had new server rooms kitted out and went for geothermal cooling, it uses a massive air handling unit to supply the cool air to the server cases but the air handling unit won't stop, I even hit the emergancy stop button on the main control unit. But it won't...

89 honda civic won't turn over [ 1 Answers ]

most of the time it starts.Is now acting up once in a while.when you push clutch to the floor you hear a click and that is all.when you keep pushing pedal to floor it will turn over eventually.Can someone please suggest what's the problem or how to fix this? THANK YOU!


View more Heating & Air Conditioning questions Search