Carrier Infinity 58MVb Code 13

Earl B · 02-12-2011, 07:38 AM

Built a new home and installed new Carrier Infinity system 95% furnace 58MVB. This winter, the furnace is tripping out several times each month. Seems to go in cycles. Will work for several weeks, then it will trip out on code 13. The furnace is in a horizontal configuration in the crawl space. I am a mechanical engineer and also have had a HVAC license. Airflow has checked out ok. Vent install is good. Dealer and Carrier field tech has visited home and tried to troubleshoot. Perplexing problem since the problem is so random. They suggested that we install the intake vent for combustion air, but I don't think this will help since it will add to the combustion air constriction. I can reset the furnace by resetting the flame rollout switch and powering off and on. Looking for solutions here? Comments?

yuri · 02-12-2011, 08:13 AM

They may be right. It may be a design issue. The ventor (combustion air inducer, goes by several different names) fan needs to suck against a minimum feet of venting on the older models (MVPs) and I worked on LOTS of them. Burner won't light/burn properly without a very specific air to fuel mixture. This resistance equals a certain airflow thru the heat exchanger which equals a certain amount of combustion air (Bernoullis principle), P1V1=P2V2 etc. Not enough combustion air and you can get a rollout. The low pressure switch and pressure switches are SUPPOSED to protect you against that but if they are out of calibration or the setting (design problem) is wrong then they won't shut you down. Adding some pipe will force the ventor to suck harder. It is an ECM motor in that ventor and may need more of a resistance to calibrate itself (ECMs are finicky that way). They design furnaces but there is NO way they can anticipate every install scenario with negative pressures in houses etc etc and that can affect the burner. After 32 yrs of seeing Lennox having revisions (in the model/series #) and every other brand, it takes at least 2-3 yrs B4 they get feedback from the field and tweak everything to get rid of nuisance tripping etc. Then they issue TSBs, technical service bulletins which only the serious techs bother to read. The rest just parts change their way thru life (another story). LOL

Earl B · 02-12-2011, 10:01 AM

The combustion vent has approx. 20 feet of vent, so we will run 20 feet of incoming vent, and that will equalize the air flow. However, it runs contrary to thought since you would think that air right out of the crawl space would be sufficient.

yuri · 02-12-2011, 10:15 AM

Nyet. Theory is one thing. Reality is another.

swcole · 10-19-2011, 09:44 AM

I am a Carrier dealer and I own the same furnace. We always install both vents to insure proper airflow through the combustion system. Intermittent outages are usually caused by water in the exhaust or condensate drain located in the furnace. Typically in the vent, the water gathers in a vent elbow that has sagged so that water gets trapped in it. Water in the condensate box is usually caused by the wrong configuration of the plastic hoses.

Code 13 is a limit lockout. This typically is caused by improper airflow into the home or a bad limit switch. Is your home zoned?? I have also seen this lockout when homes are ducted overhead with overhead returns and the furnace is overheating. This can be fixed by relocating the return duct through a closet to get them closer to the floor.

Good luck and hopefully this helps.