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BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22012
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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My bryant gas heater is displaying a code 13 limit switch lockout

Customer Question

My bryant gas heater is displaying a code 13 limit switch lockout and after 3 hours and the manual reset has been activated it comes on and works till the thermostat reads about 60-61 degrees and then shuts off. I've replaced the air filter and used some sandpaper to clean off the sensor rod that sits on the left side of the burner.

Submitted: 5 years ago.
Category: HVAC
Expert:  BillyHvac replied 5 years ago.


When you press the manual reset button, does it enable the unit to kick on and run again?

Customer: replied 5 years ago.

When I push the click button in for like 3 seconds, it turns the big fan blower in the bottom of the heater; so I'm guessing yes.

Expert:  BillyHvac replied 5 years ago.

Do you know where the limit is on the front wall? Rectangle flat plate 3"x4" with 2 wires hooked to it?

Customer: replied 5 years ago.

The only switches I'm able to find currently are the side of the blower/igniter box and the one that is right under the control board. I'm not sure which way is the front. The switch on the right side has two red wires attached to it. That is the one I tested with the ohm meter and the one I just switched on. After switching it on when on my second email it finally just came on and the burners just recently kicked on and the code 13 just went away and is now a solid red on the led light. Like I said, it comes on and heats up to about 61 degrees approximately then shuts off even though the heater thermostat is set to 67 degrees.

Expert:  BillyHvac replied 5 years ago.

Ok, thank you. It sounds as though you have a bad heat exchanger. The roll out switch is there for when the flame goes out of the exchanger and washes back. You will really need to have the exchanger tested to see if cracked or plugged.

Customer: replied 5 years ago.

I have some other ideas on what the cause of the problem might be after I did some googling. According to this link:

they mention that having excessive water build up in in the inducer motor might cause the problem with the pressure switch. So I checked the collector box drain tube and it had lots of water drain out of it. So I then pulled off the larger condensate trap tube (there are two of them) that is coming off the back side of the inducer motor. I did this after noticing a pool of water in the back left corner that was beading up just under that tube. The inducer motor was running when I pulled this tube off and no water come out of the tube, but I could hear some weird noise that sounded sort of liquidy. So for some reason when I turned off the power to the heater and a whole bunch of water come out of the hose that connected the inducer motor to the condensate trap. What do you make of this issue?

Expert:  BillyHvac replied 5 years ago.

Not relevant information.

The secondary can have certain cells plugged but if water is backed up the pressure switch cannot make contact thus leading to a different code.

I am a factory trained Carrier, Bryant, Payne tech for over 20 years....I can tell you with 100% that if the roll out is tripping consistently it is a bad exchanger or plugged...

Water drain issue = pressure switch code.

Customer: replied 5 years ago.

Well I'm sorry I'm not trying to dispute any of your technical expertise at all, there could indeed still be something wrong with the heat exchanger still for all I know. All I'm trying to do is come up with a solution looking for what ever is not working the way it should be in this heater. Its quite possible that my description of the problems and things I tried got messed up when I tried to explain them to you. All I know is I removed the water from the hose that goes from the tranducer motor to the condensate trap seems to have made the heater get past the 60 degree threshold when the code would go off and shut down the heater. I hope that the water trap isn't clogged up (I didn't check this) cause it looked like it would be tricky to get out, for replacement if that is even possible. Have you ever seen a heater display the wrong codes, just wondering?

Expert:  BillyHvac replied 5 years ago.

I know you are hoping and searching for a better suited diagnosis. But the reality is the roll out is there for one reason....a bad or plugged exchanger.

It is not what we want to hear. I can tell you the Carrier/Bryant 90% furnaces had a real issue with exchangers. They bumped them from 20 year to lifetime warranty due to class action court procedures. They supply the exchanger and cover 4 hours labor.

Usually the customer has about $300 additional cost into job.

Since this is one of the more critical events a furnace can face, I recommend a service call to verify the findings.

This is not just inconvenient, this is dangerous. The roll out is the main protection against C.O. poisoning and fire caused by furnace.

This is the most important safety on the entire furnace.

Customer: replied 5 years ago.

Thanks for your help. I will take your advice into consideration in the event that I have further 13 codes pop up on me, but for right now its working. According to the information I gathered from the internet which may or may not be correct, was that if I test the rollout switch with the ohm meter periodically to see if it reads anything else other then zero, its defective. Is this correct? If this is the case then I can keep an eye on this critical safety measure down the road to help avoid this potential critical problem from happening.

Expert:  BillyHvac replied 5 years ago.

Correct, the roll out is either open or closed so ohming is very definitive or check for 24v in and out.