Emergent Furnace Replacement

[MSIKE]

Hello,

My fiance is back home, taking care of my house. She informed me that the furnace was blowing but, not warm air. I told her to check the pilot light, and she said it was out. She refused to follow the simple instructions (that I used twice in the 3 years I lived there, without incident) and relight the pilot light. So, my neighbors use an HVAC guy for all of their heating and cooling needs, and they referred him to my fiance. This afternoon, I received and email from her, post inspection, stating that I was in need of a new furnace, and that if it were to run it would kill anyone in the house within 3 hours, due to CO poisoning (though she wrote Co2 in her email)... It is an old Lennox furnace, from 1984, but the model escapes me at the moment. In any event, I am curious as to how the furnace that was inspected in late 2007 when I bought the house, has deteriorated to the point of emitting such high levels of CO over a period of four years. She told me that there was a smell in the basement, and was told that was the scent of CO (or Co2), both odorless, mixed with something - "He also said that's what that lingering smell was in the basement...it's not the co2, but the stuff it's mixed with."

Any guidance you can provide would be greatly appreciated. I know that I need to replace the furnace in the near future, but my gut instinct tells me that there are no immediate health concerns.

Her -
“The pilot light still didn't stay lit. Then, when it did the fire was huge...he said it had a lot of CO2 in it, but was hoping it would burn off. Well, it didn't and he tested the air and the CO2 levels were off the charts.”

[juster]

By law a mechanic must shut down and lock off a furnace that is deemed to have a faulty heat exchanger. This will cause CO in your house when the unit is running. If the mechanic locked it off then he did the correct thing. If he did not, shut down the unit and do not try to use it. It will kill who ever is in the house. Get a quote from the first contractor. If the temperature is not an issue at this time. (cold in the house)You can call for a second opinion and quote. If temperature is an issue. Then you will need to work quickly to get a new furnace ASAP.

[heatseeker]

For one thing most home inspectors don't know squat about cracked heat exchangers, If your unit is that old get a new one please don't be cheap.

[Freon]

Before you do anything, have another HVAC person inspect the system and tell you precisely where the crack is. Pilot lights go out for many reasons and since you have given very few details, it's hard to make an educated assessment.

In most furnaces the blower is located before the heat exchanger. Therefore, once the blower starts circulating air in the house, the air pressure in the house air side of the heat exchanger is greater than the pressure in the combustion side of the heat exchanger. Any CO, if there at all, will not flow into the house air due to the pressure difference. CO is a byproduct of poor combustion so if your furnace does have reasonably good (efficient) combustion (blue flame, not yellow, assuming gas), the amount of CO should be very low.

Sadly, too many HVAC people like to condemn systems so they can sell you a replacement. The HVAC industry is no worse than any service industry... there are rotten apples in all service industries.

The reason the pilot is not staying lit is important. It might be a sensing issue or there could be a crack in the heat exchanger causing the high pressure house air side to blow into the combustion chamber and thereby extinguish the pilot. Again, get another opinion and ask where the crack is and how the tech determined it was cracked.

[MSIKE]

Thanks for your help!

[heatseeker]

Um hello--- you still have a furnace with a pilot * They have been obsolete for 20 years. If your furnace is that old the best advice anyone can give you is replace your inefficient piece of junk while you still can. If you can't afford it then you should take a home improvement loan, a good furnace shouldn't cost over 2 grand and it improves your house value. When it's time it's time stop being cheap when it comes to safety.