I have a Carrier 59SC2B. I think it is single stage.

I have had the unit for 3 winters now and this is the first winter that I am experiencing alot of problems. What is happening is: (the LED light is continuous throughout the whole process and never lights any error code. Flame sensor has been cleaned)

  1. Furnace gets a call for heat from thermostat
  2. The Inducer blower motor then starts
  3. The igniter lights up bright orange
  4. the igniter shuts off without any flame
  5. inducer continues to run
  6. igniter lights up again and then dims without any flames
  7. heavy water gurgling, or bubbling sounds from condensate trap
  8. after some time (~1 hour), if without any intervention, the flames start and indoor blower fan starts.

    a. If I go into the unit and pull out the interior condensate drain pipe, wiggle/jiggle the water out, plug it back in, the flames start on the next igniter light. (Is this pipe supposed to be pitched downward toward the PVC drain? It looks 100% flat/horizontal)

Is it the condensate drain? I took the condensate trap out to clean it already, its fairly good. Is it because somehow this winter I am experiencing abnormal levels of condensate and the furnace is simply doing what its supposed to?


EDIT (1/26): It is taking 1 hour again and I have called a HVAC tech to come in but I am worried he probably won't find anything because given enough time, the furnace starts to work. I've made a video of what is happening, perhaps someone has seen this before. It is recorded as soon as I restart the furnace and the induction motor kicks in. https://www.youtube.com/watch?v=aH7Dtx3Ht5U

  • Not sure if this is your issue, possibly hvacrecalls.com/wp-content/uploads/2016/03/dsb14-0002-TIC7.pdf
    – Tyson
    Dec 26, 2016 at 3:53
  • Thanks...I actually did that about 1 hour ago. Still same issue. BTW do I need to file/sand the hole that was enlarged? Dec 26, 2016 at 3:57
  • Can you provide photos of the condensate drain? Maybe we'll be able to spot a problem. The gurgling/bubbling sounds indicate that the condensate is not draining properly, which is likely causing the pressure switch(es) to not close.
    – Tester101
    Dec 27, 2016 at 12:41
  • Well it is hard to get a picture of the pitch of the drain...but lately it takes about 30 minute to get going which is an improvement. It isn't that the furnace isn't working it just takes a few tries before it starts. I am just wondering if this is intended. Dec 31, 2016 at 18:55

1 Answer 1


The pressure switch was faulty (sticking)

Normal operation should not be more than 5 minutes to start the flames.

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