Carrier Gas Furnace only works for one cycle after reset


  #1  
Old 10-22-13, 08:08 AM
J
Member
Thread Starter
Join Date: Oct 2013
Location: USA
Posts: 3
Received 0 Votes on 0 Posts
Help please! Carrier Gas Furnace only works for one cycle

Hello,

We bought a condo in the summer and now the furnace has some problem. Some help is greatly appreciated.

It is Carrier 58STA070-12 installed year 2005. The sequence is briefly as below:
1. Turn on the furnace power (after ~1 hour off)
2. Turn on the thermostat with Temp setting higher than room temp.
3. the inducer motor comes on, about 10 seconds later the ignitor lights up, 5 second later flames come on, and heat gets into the condo.
4. furnace shuts off when set temp is reaches.
5. after the temperature drops about 2 degrees, I can see the thermostat shows "heat" and hear the click from thermostat, but the inducer motor wouldn't come on to start the sequence.
6. There is a red light rapidly flashing, the code said reversed polarity, but nobody has touched it, and we checked the polarity is fine.

We have to turn off the furnace power switch (turning off the thermostat wouldn't do it) for >30minutes to start the whole sequence, and it runs for one cycle and stops. We also tried a new thermostat, it has exactly the same problem.

One technician came and doubted the control board, but not sure. I want to ask if anybody here have any suggestions on what else to test before we spends $$$ to replace the board then figured it was not the problem. I am pretty handy and have a lot of tools and can do some tests if suggested.

Thank you all,
 

Last edited by JuneP; 10-22-13 at 09:40 AM.
  #2  
Old 10-22-13, 06:00 PM
G
Member
Join Date: Dec 2007
Location: USA
Posts: 239
Received 0 Votes on 0 Posts
How did you check polarity?

Replacing the control board might be something you can do yourself, you might ask the pros on this board if there is a trick. Take detailed pictures of it and label wires so you know how to get stuff in the right place.
 
  #3  
Old 10-22-13, 06:56 PM
SeattlePioneer's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2007
Location: Seattle, Wa
Posts: 5,499
Received 0 Votes on 0 Posts
Very likely the circuit board is bad and needs to be replaced.

Use a multimeter and measure the AC voltage from the W to the C terminals.

When the tyhermostat calls for heat, you should get 24 VAC on the W terminal and the inducer motor should start up. If it doesn't replace the circuit board.
 
  #4  
Old 10-23-13, 06:59 AM
J
Member
Thread Starter
Join Date: Oct 2013
Location: USA
Posts: 3
Received 0 Votes on 0 Posts
Thank you for your reply! I have a couple more questions

Thank you guys!

I didn't measure the polarity, the guy who came said it is impossible (not sure how/if he measured it) to suddenly have reversed polarity after 8 years of usage, because nobody was messing with it.

When we the thermostat sends heat for the first time when we turn on the furnace (after switching it off >30minutes), the inducer comes right up, so I assume it is getting 24VAC. the whole sequence starts and condo is warm .

But after the temperature drops a few degree, and thermostat calls for hear, we did get 24VAC at W terminal, but the inducer wouldn't turn on. and nothing else turns on either. I don't understand how come it works after furnace power off for 1 hour, but doesn't work after one cycle.

Please let me know if there is something else I should check , maybe wiring of the inducer or something? Otherwise I guess we will order the board. Any recommended website to order parts? I found this place, is it trustworthy? HVACpartsoutlet.com

Thank you very much for any thoughts and suggestions.
 
  #5  
Old 10-23-13, 08:19 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,828
Received 1,473 Votes on 1,361 Posts
With the 24vac on the W terminal and the inducer blower not responding it does appear to be a control board problem.

While you are messing around in there make sure all the ground screws to the board and nearby components are clean and tight. A weak/missing ground can cause strange issues.
 
  #6  
Old 10-29-13, 01:39 PM
J
Member
Thread Starter
Join Date: Oct 2013
Location: USA
Posts: 3
Received 0 Votes on 0 Posts
It is working now!

Hi, Guys,

I want to thank all of you for your help. We ordered a replacement control board ICM aftermarket product. We exchanged the board ourselves, and it has been working since the weekend! In time fix since we had friends over on Sunday.

Thank you all again,
JuneP
 
  #7  
Old 10-29-13, 03:58 PM
SeattlePioneer's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2007
Location: Seattle, Wa
Posts: 5,499
Received 0 Votes on 0 Posts
Polarity faults often don't actually exist and are a common symptom of a bad circuit board.

Still, double checking the polarity is the right thing to do ---- sometimes wiring changes are made that homeowners might not be aware of.
 
 

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