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 06-18-2010, 01:11 AM   #1
Newbie
 
Join Date: May 2010
Posts: 10
Rewards Points: 10
Default

please help, have made progress, AC still won't start


So, I have had lots of help on this forum, thanks for that.

I have replaced my thermostat, transformer (in air handler) and contactor on AC unit outdoors.

My AC will still not run when I set the thermostat to AC. I do have heat and the blower (fan) works.

What next? I am not sure if the AC unit is getting 24v to engage the contactor. If I press the contactor it will engage manually. Is the problem the capacitor in the AC unit or a time delay switch or since I have no low voltage power voltage leaving the circuit board heading to the AC unit. Everything else appears to have power.

Thanks for your continued help. I'm almost there!

MC

diywhy is offline   Reply With Quote
Old 06-18-2010, 03:06 AM   #2
Member
 
hvaclover's Avatar
 
Join Date: Oct 2008
Location: Suburbs of Detroit Mi
Posts: 3,704
Rewards Points: 2,000
Default

please help, have made progress, AC still won't start


Quote:
Originally Posted by diywhy View Post
So, I have had lots of help on this forum, thanks for that.

I have replaced my thermostat, transformer (in air handler) and cont actor on AC unit outdoors.

My AC will still not run when I set the thermostat to AC. I do have heat and the blower (fan) works.

What next? I am not sure if the AC unit is getting V to engage the contactor. If I press the contactor it will engage manually. Is the problem the capacitor in the AC unit or a time delay switch or since I have no low voltage power voltage leaving the circuit board heading to the AC unit. Everything else appears to have power.






Thanks for your continued help. I'm almost there!

MC
Ok if your outside unit kicks in manually, than you must determine if you have 24VOLTS to the contactor.

Need to see first off if the ah has a control board. There is a fues that could be blown.

If you have no 24v you neeed to check each part.

__________________
Just slow, not stupid.
hvaclover is offline   Reply With Quote
Old 06-18-2010, 07:52 AM   #3
Member
 
Join Date: Nov 2006
Posts: 291
Rewards Points: 250
Default

please help, have made progress, AC still won't start


Quote:
Originally Posted by diywhy View Post
So, I have had lots of help on this forum, thanks for that.

I have replaced my thermostat, transformer (in air handler) and contactor on AC unit outdoors.

My AC will still not run when I set the thermostat to AC. I do have heat and the blower (fan) works.

What next? I am not sure if the AC unit is getting 24v to engage the contactor. If I press the contactor it will engage manually. Is the problem the capacitor in the AC unit or a time delay switch or since I have no low voltage power voltage leaving the circuit board heading to the AC unit. Everything else appears to have power.

Thanks for your continued help. I'm almost there!

MC
It sounds like you're randomly replacing a lot of parts in hopes of getting your system running. Let's try some systematic troubleshooting instead of "tea bagging".

1. First off pull the AC units disconnect so you don't electrocute yourself.

2. Do you have 24VAC coming into the control unit of the AC? If not you need to trace the wiring back to the AH, and the AH control board low voltage xformer.

3. If you have 24VAC power at the AC unit, do you have the signal to engage the contactor when the system calls for AC? If not then backtrack your control wiring back to the AH and thermostat.

4. If the low voltage control system at the AC tests OK but the contactor still won't engage then your problem is probably the AC's control board/wiring or maybe the protection circuitry. (ie the low pressure switch prevents the system from running if it's low on refrigerant pressure and the countdown timer prevents frequent startups).

5. The fact that the unit started when you manually engaged the contactor likely rules out things like compressor or capacitor.

Post what you find from the above.
hennyh is offline   Reply With Quote
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Air Compressor blowing start capacitors? BBC3 Electrical 9 04-28-2013 11:34 AM
Milwaukee tool made in China KUIPORNG Tools 63 08-31-2011 01:10 PM
clare furnace needs reset to start dustin020 HVAC 2 10-15-2009 06:06 PM
Blue smoke at start up, and shudder at idle fauer Automotive Repairs 6 08-22-2008 11:39 AM
Mower won't start, anything I can try before bringing it to the shop? joeyboy Landscaping & Lawn Care 6 08-05-2008 02:08 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.