# Carrier furnace help code 13



## mudtruck

:wink:well It seams I might have made a mistake not sure but I have to go home and recheak the led light it might be a code 31 instead so If anyone can help me with this I would greatly appreciate it .thanks


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## HVACDave

Hi Mudtruck,

To determine if it is code 13 or 31... The first digit is the number of short flashes, and the second digit is the number of long flashes.

13 is limit circuit lockout, in which case your furnace would try and restart after 3 hours. The limit circuit is there to protect the furnace from overheating if there is insufficient airflow through the heat exchanger taking the heat away from the furnace and pushing it into your ductwork. If this is the code then look for plugged air filters, blocked discharge vents, etc.

31 is the pressure switch didn't close or reopened. This pressure switch is in your furnace to monitor the combustion fan motor to prove you have positive exhaust gas pressure out of your exhaust vent and through your combustion chamber. This could be triggered due to plugged intake and/or exhaust piping, defective exhaust blower fan, excessive wind, plugged tubing on the pressure switch, etc. These pressure switches are very sensitive, do not take the hoses off and blow into the switch or you will damage it. I have also seen where an improper grade on the furnace will cause this fault. It should have a slope of about an 1/8th of an inch from the back to the front of the unit, if not you may build up condensate in the secondary heat exchanger and not get enough flow through the vent motor.

Both of these conditions can be reset by turning off the power to your furnace and then turning it back on. The furnace will then go through its normal start-up procedure.

Have a look at your vents outside and make sure that there haven't been any birds taking up residence in your vent pipes, also check your condensate drain line to make sure it isn't plugged.

Good luck, if in doubt get it checked out by a pro, this isn't a trade you want to mess with if you aren't comfortable with it.


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## pengu1n

Not too often I register to say thanks. Woke up at 5am Saturday to let the dogs out. Thermostat reads 63. What!? Take off thermostat, try redoing program, turn off circuit breaker to furnace, nothing working. I shudder at what this is going to cost, especially on a weekend. 
Take off the front panel of my furnace (carrier) and take a look around. Notice blinking LED. 1 long, 3 short...code 31 according to what I could find on the internet. Search on Carrier code 31 in google and run across this page. I check everything and it looks like a snowball is in my outdoor vent. It's under my deck with a downward facing elbow joint, so maybe I need to look for footprints in the morning and talk to the neighbor kids. 
Clear the snowball out and go flip the breaker back on. HEAT! 
Thank you for having this forum.
-Pengu1n


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## mudtruck

Just wanted to say thanks to HVACDave I replaced the pressure switch and It now works beautifully saved me a lot of money. And thanks for this forum I love it.


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## fauxjaux

*where is the pressure switch?*

Hi HVACDave, 

I read your post and wanted to ask for your help. I have a Carrier 58 RAV, restarted it, tripped all the limit swithcs, sanded the flame sensor, and then noticed a LED is flashing three short and one long, indicating a code 31 i learned from your post, but looking at an online manual, 
http://www.esmithair.com/support/Carrier/58_PAV_58RAV_Gas_Furnace.pdf 
I couldn't find a pressure switch. is it in the control valve? 

The pros in my area is overwhelmed with new construction work, and told me 6 to 12 weeks to get out to my place, which is out of town a long way.

I am very comfortable with plumbing and wiring.

I hate to bother you with this, but it is still cold some nights here in Colorado.

Thanks in advance

Fojo





HVACDave said:


> Hi Mudtruck,
> 
> To determine if it is code 13 or 31. The first digit is the number of short flashes, the second digit is the number of long flashes.
> 
> 13 is limit circuit lockout, in which case your furnace would try and restart after 3 hours. The limit circuit is there to protect the furnace from overheating if there is insufficient airflow through the heat exchanger taking the heat away from the furnace and pushing it into your ductwork. If this is the code then look for plugged air filters, blocked discharge vents, etc.
> 
> 31 is the pressure switch didn't close or reopened. This pressure switch is in your furnace to monitor the combustion fan motor to prove you have positive exhaust gas pressure out your exhaust vent and through your combustion chamber. This could be triggered due to plugged intake and/or exhaust piping, defective exhaust blower fan, excessive wind, plugged tubing on the pressure switch, etc. These pressure switches are very sensitive, do not take the hoses off and blow into the switch or you will damage it. I have also seen where an improper grade on the furnace will cause this fault. It should have a slope of about an 1/8 th of an inch from the back to the front of the unit, if not you may build up condensate in the secondary heat exchanger and not get enough flow through the ventor motor.
> 
> both of these conditions can be reset by turning off the power to your furnace and then turning it back on. The furnace will then go through its normal start up procedure.
> 
> Have a look at your vents outside and make sure that there haven't been any birds taking up residence in your vent pipes, also check your condensate drain ine to make sure it isn't plugged.
> 
> good luck, if in doubt get it checked out by a pro, this isn't a trade you want to mess with if you aren't comfortable with it.


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## vicmata01

I am having an issue with the same type of furnace. My LED light is staying on after the recycle. Not sure what it is.


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## HVACTECH96

Steady on light means no faults


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## KITZ70

I have a carrier58pav111-12 i have a solid red led no flashing at this time, any one have a suggestion


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## Baiter

KITZ70 said:


> I have a carrier58pav111-12 i have a solid red led no flashing at this time, any one have a suggestion


no flashing lights indicate operation normal NO CALL FOR HEAT. indicates low battery if digital, heat anticipate issue if manual thermostat. or stat wire issue.


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## Baiter

pengu1n said:


> Not too often I register to say thanks. Woke up at 5am Saturday to let the dogs out. Thermostat reads 63. What!? Take off thermostat, try redoing program, turn off circuit breaker to furnace, nothing working. I shudder at what this is going to cost, especially on a weekend.
> Take off the front panel of my furnace (carrier) and take a look around. Notice blinking LED. 1 long, 3 short...code 31 according to what I could find on the internet. Search on Carrier code 31 in google and run across this page. I check everything and it looks like a snowball is in my outdoor vent. It's under my deck with a downward facing elbow joint, so maybe I need to look for footprints in the morning and talk to the neighbor kids.
> Clear the snowball out and go flip the breaker back on. HEAT!
> Thank you for having this forum.
> -Pengu1n


More than once on a high efficient model Ive seen the units create its own snowball by twirling the snow around. and stuff itself in. there very well could be no kid doing it. but an act of mother nature.


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