Bryant Control Board-No a/c power?


  #1  
Old 08-27-08, 09:45 AM
J
Member
Thread Starter
Join Date: Aug 2008
Location: Southern California
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
Bryant Control Board-No a/c power?

Could use some expert help here. I tried to help a neighbor who had trouble installing a new thermostat. He didnít turn off the power to the system and short circuited the wiring in the process. Then of course nothing worked. The system is a Bryant forced air heater in the attic with a split a/c system with the compressor outside the house. The Forced air unit is a Bryant model number 310JAV048090 made in 2003. I found the 3 amp fuse on the control board blown and after rewiring the thermostat correctly and replacing the fuse powered the system back up. The heater works, but the A/C does not. I can go out side and push the contacts on the outside A/C unit and it runs fine. There is 28 volts coming out of the control board in a few locations and trying to put the system in to test doesnít seem to work. The fan will not come on manually only with the heater on. There doesnít seem to be any low voltage power on the cooling side or the fan. I tried jumping from the common 24v to Y, is that a correct thing to do? Nothing happens. Do I need a new control board or does the blowing of the fuse protect it from damage?
 
  #2  
Old 08-27-08, 02:30 PM
Jarredsdad's Avatar
Member
Join Date: Oct 2002
Location: Troy, VA
Posts: 1,392
Upvotes: 0
Received 0 Upvotes on 0 Posts
We'll need to know what is wired to what. From the stat, Y,R,C,G,W, then at the airhandler the same points and then at the outdoor unit.

There is 28 volts at various points? Which ones?

Y to R should bring on the compressor.
 
  #3  
Old 08-27-08, 05:48 PM
E
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 7,826
Upvotes: 0
Received 1 Upvote on 1 Post
Sounds like you already did the jumper test. But where exactly did yo do it?; at the stat?, or in the handler where the low voltage terminal block is? It does make it sound then like it is the board, (if you did the R to Y test in the handler itself).

Have you taken a close look at all the soldered conections on the board, to see if you can actually see something that got arced? If you did, then you would pretty much know. And then you'd also have the option to try to solder in the new part or buy entire new board.

You could also do a continuity test of the low volt wires between the handler and outdoor unit, to make sure that wire does not have a break in it.

Also make sure any low volt connection is tight, in case the arcing caused a bad connection at either end. And perhaps slip off and back on every spade connector on the board. This would especially be a good idea if you do NOT find any arced spots on the control board.
 
  #4  
Old 08-29-08, 08:12 AM
J
Member
Thread Starter
Join Date: Aug 2008
Location: Southern California
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
will need some more checking

Thank you for the help so far. I'm going to go back to get an accurate list of what voltages I'm finding and where and how the controls are wired.
The one good thing I thought of because of the replies you have given me, is to go to the unit next door and check their board to compare readings. The neighbor helped the guy I'm helping to screw things up in the first place.
 
  #5  
Old 08-29-08, 04:12 PM
Jarredsdad's Avatar
Member
Join Date: Oct 2002
Location: Troy, VA
Posts: 1,392
Upvotes: 0
Received 0 Upvotes on 0 Posts
Very astute course of action. Tells me we are dealing with a person of logical thinking.

Draw your own diagram of connection point between stat, a/h, and cond.

Follow the path of voltage and determine where the break is.

While Bryant is part of Carrier, I can't get any info (wiring diagrams) from the Carrier website.

Perhaps someone else can?

Also heed ecman's post.
 
 

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