u/Confident_Fig6222

Hi everyone,

We had a carrier/bryant furnace installed in 2011. It's been good overall since then (writing in April, 2026), but we had to get some motor part repaired in October, 2025 that cost $1,500. At the time the guy said the furnace looked good otherwise.

Fast forward to last night: we got a malfunction code on the thermostat that said there was an issue with the outside temperature monitor. We do not have a humidifier, so that function only tells us outdoor temp and humidity. Furnace seemed to still be doing okay. Middle of the night last night and the furnace was not working and there was another error code. I shut off furnace and restarted it and seemed to be okay. In morning error code was on and furnace was not working.

Just had a couple service guys out. They said the code was for the 'pressure switches' and said when they restarted system and hit pressure switch lightly with a flashlight it started up again. They looked at some diagnostic stuff and said that the 'heat exchangers' in these furnaces are problematic. He showed me images that he said showed little yellow 'boogers' accumulating in a way in part of the system that indicates there is a developing issue with the heat exhanger. He said that I could pay a bit over $500 for the pressure switches to be replaced, but that it is a temporary fix and that the heat exchanger will eventually need replacement too. He said that costs $3800 but could be as low as $2500 if it's under warranty because we had the furnace installed.

We are having someone come out in a bit to give us some quotes on a new system, but I want to see what you all think about this story. I'm hesitant to put more money into an old system that has indications of an issue that will be too costly to prepare down the road, but I'm also super bummed about having to get a new furnace when we just put $1500 into it a few months ago and were told it looked great.

The company said they install Lennox furnaces and that they are good. We are in Minneapolis.

thanks for any thoughts/advice/experiences with this.

Hi everyone,

We had a carrier/bryant furnace installed in 2011. It's been good overall since then (writing in April, 2026), but we had to get some motor part repaired in October, 2025 that cost $1,500. At the time the guy said the furnace looked good otherwise.

Fast forward to last night: we got a malfunction code on the thermostat that said there was an issue with the outside temperature monitor. We do not have a humidifier, so that function only tells us outdoor temp and humidity. Furnace seemed to still be doing okay. Middle of the night last night and the furnace was not working and there was another error code. I shut off furnace and restarted it and seemed to be okay. In morning error code was on and furnace was not working.

Just had a couple service guys out. They said the code was for the 'pressure switches' and said when they restarted system and hit pressure switch lightly with a flashlight it started up again. They looked at some diagnostic stuff and said that the 'heat exchangers' in these furnaces are problematic. He showed me images that he said showed little yellow 'boogers' accumulating in a way in part of the system that indicates there is a developing issue with the heat exhanger. He said that I could pay a bit over $500 for the pressure switches to be replaced, but that it is a temporary fix and that the heat exchanger will eventually need replacement too. He said that costs $3800 but could be as low as $2500 if it's under warranty because we had the furnace installed.

We are having someone come out in a bit to give us some quotes on a new system, but I want to see what you all think about this story. I'm hesitant to put more money into an old system that has indications of an issue that will be too costly to prepare down the road, but I'm also super bummed about having to get a new furnace when we just put $1500 into it a few months ago and were told it looked great.

The company said they install Lennox furnaces and that they are good. We are in Minneapolis.

thanks for any thoughts/advice/experiences with this.