Goodman Furnace Model# GMEC960603BNAB
Furnace is about two years old. We moved into our new home built in 2018 this fall and this is our first winter. We've been having problems with the furnace operation as it seems to cycle on and off every 5 mins or so and could take a while for our rooms to get heated up.

In preparation for the winter, we had a HVAC company come in to do a PM a few months back to ensure it was in good shape. The following was done:

*blew out condensate and pressure tubes. Ok
*checked all the wiring for loose connections. Ok
*checked the squirrel cage and motor to ensure fan isn’t coming loose or breaking
*condensate pump ran
*checked the flame sensor and ignitor. Ok
*cleaned out the burner tray
*checked the burner tubes. Ok

I also have been changing the filter out every month as we have some cats. All the registers are open and unrestricted. When we do get heat it comes out with good airflow.

When we adjust the thermostat, the furnace will kick on, we will hear the fan, a steady green light will remain on. Then I can see the heating element glow and the burners start, the light will blink amber indicating the burners are firing. After 5 minutes, the burners shut off and I can see the light blink 4 times red. The manual shows this is "Open high limit". I can see the limit switch in the center under the burner, is it defective? Is there another way I can troubleshoot this? Kind of losing my mind as i'm worried that this cycling is harming the system in the long run...

 

Hi, according to this site there are dip switches that need to be configured for the particular systems, this could effect blower performance and higher temperatures which could cause a Hi limit to open.
https://www.jmrmax.com/gmec96.pdf
Geo🇺🇸

 

Welcome to the forums.

Your HVAC company needs to a heat rise test. They test the return air and compare it to the supply air. The heat rise is listed on the ID tag inside the furnace. They may be able to adjust blower speed. They should also check gas manifold pressure to make sure the burners aren't over firing.

If this is beyond your service company.... call your gas provider. They usually have competent technicians and their prices are reasonable.

 

Thanks Pete,

We have a buried propane tank that supplies gas. Not sure if the company that fills it has this specialized experience but I'll look around for sure.

When we had our home inspection, I recall the inspector did check the air flow in the vents and deemed it acceptable. I'll need to track down their report.

 

Propane companies are different when it comes to service.
They typically aren't large companies like the natural gas companies.


Your furnace is running on propane. Propane furnaces are more dependent on proper fuel pressures.

 

I picked up new limit switches (manual reset and primary) and flame sensors under $30 bucks and will attempt to replace them first to see whats going on before taking next steps calling a profe$$ional. Thanks for the feedback all.

 

The plot thickens. So when I run the furnace without the filter it is a champ! What's strange is that I picked up the cheapest home depot non-pleated fiberglass filter (wide open!) and when it was installed the same high limit error tripped. I'm thinking the high limit sensor is bad because how can even the fiberglass be too restrictive to airflow!? doesnt make any sense...

 

Sounds like your furnace is overfiring. Get it checked.
A good tech should be able to check static pressure too which will give an indication of duct issues.