Contactor Issue

Reply

  #1  
Old 12-18-10, 03:38 PM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 7
Received 0 Votes on 0 Posts
Contactor Issue

I recently replaced the fan motor that fried on my unit. When looking at the inside of the unit everything was very old and rusty so I replaced contactor, capacitor, and thermostat too. Worked great for about 2 days. Now the air handler indoors works, but the outside unit does not turn on. Every once in a while I here a clicking sound like the contactor is trying to engage. I press down the contactor manually and the system works fine. I remove the low voltage wires from the contactor and measured the voltage. It is a little high at 26V as opposed to 24V. Not sure if this matters. I replaced the contactor again with another new one and get the same results. Any suggestions. Thanks.
 
Sponsored Links
  #2  
Old 12-18-10, 04:08 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,373
Received 10 Votes on 8 Posts
Possibly a low pressure switch lockout due to refrigerant leak.
Do you have a 5 minute time delay relay at your outdoor unit?
 
  #3  
Old 12-18-10, 05:19 PM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 7
Received 0 Votes on 0 Posts
Yes, I do have a time delay relay. At one point I thought that was the problem. However, since I am getting enough current coming through with it in the loop I am assuming it is not. Is this a bad assumption? Not sure how to test for the other thing you mentioned.
 
  #4  
Old 12-18-10, 06:37 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,373
Received 10 Votes on 8 Posts
Can you see the coil voltage writtten on the contactor?
If not, do you have the part number for this contactor?

You might remove power to your outdoor unit, remove the low voltage wires from your contactor and check if a 9 volt battery will pull in the contactor.

I have seen a small lizard in the contactor cause this before.
I have seen a faulty stat cause this before (jumping the stat prooved this).
 
  #5  
Old 12-18-10, 06:47 PM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 7
Received 0 Votes on 0 Posts
Coil voltage is 24v.

Honeywell, Single Pole 24 Volt Air Conditioner Contactor
Part #DP1030A 5013
 
  #6  
Old 12-18-10, 06:57 PM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 7
Received 0 Votes on 0 Posts
9V battery does pull the contactor.
 
  #7  
Old 12-18-10, 07:51 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,373
Received 10 Votes on 8 Posts
R = 24VAC
Y = compressor
G = fan
W = heat
C = common

Removing the stat and wire nutting R, G and Y will bypass the stat and energize the contactor. (avoid common)
Turn off power to units to wire nut and restore power to test.
 
  #8  
Old 12-18-10, 09:07 PM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 7
Received 0 Votes on 0 Posts
Had done that already from scanning through the forum before posting. Did it again anyway just to make sure. Inside unit came on. Outside unit sparked at the contactor when the electricity was restored, but the contactor did not engage.
 
  #9  
Old 12-18-10, 09:33 PM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 7
Received 0 Votes on 0 Posts
I am obviously not very knowledgeable about electricity. I was under the impression that the contactor needed 24v to engage. It is engaging under the 9V from the battery test you suggested. Is the voltage being too high (26V+) the issue? Could I need to replace the transformer?
 
  #10  
Old 12-18-10, 10:05 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,373
Received 10 Votes on 8 Posts
I've seen this with stat wire thinner than 18 gauge matched with longer runs.
28VAC would be better.

Will it work when you bypass the timer?
 
  #11  
Old 12-19-10, 07:09 AM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 7
Received 0 Votes on 0 Posts
It is the time delay. When I take it out, everything runs smoothly. I guess I mistakenly thought if I received current with it in line that it must be fine. Thanks for all your help with this.
 
  #12  
Old 12-19-10, 08:58 AM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,373
Received 10 Votes on 8 Posts
This timer protects the compressor from short cycling. It can extend the life of your compressor. A digital stat can remove the need for it. (Most digital stats have this timer)
 
Reply

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


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: