HELP!!! Furnace problems and 2 babies!!!

[Liceaga]

Hello. First let me say that I've been reading your forum and am very impressed with the knowledge of all you HVAC folk!

I have a Lennox G12 60,000 btu 80% eff. furnace. It's at least 20 years old. Occassionally I've heard some explosion sounds (BANG!) and couldn't quite pinpoint what it was. Well, Wednesday night, three explosions in a row and flames shooting out of the furnace cover! This happened at 4:30 am and scared me half to death. I have two babies and am just waiting for the house to burn down! (Currently staying at grandma's.) Here's the other pertinent info-

We had someone inspect the furnace and the filters were caked with lint. My husband thinks this could have caused the explosions- lint falling down onto the flames, etc. Is this a correct assumption?

The repair tech said that- pardon the lack of technological terms- one of the valves or something like that was very clogged which in his experience 99.9% of the time indicated a cracked heat exchanger. He could not physically see any cracks but I understand that only a small portion of the heat exchanger is visible in this type of furnace. He advised us not to use the furnace.

We have carbon monoxide detectors in the house- near the furnace- and an explosive gas detector as well. These have never alarmed. My husband has pointed this out many times and stayed at home last night with the furnace working fine. (He replaced the filters.) I am afraid to take the kids back home and have it in my head that we HAVE to have a new furnace. He is trying to convince me that this isn't necessarily true and says that many repair techs say the heat exchanger is cracked to get a furnace sale. Tonight he is going home to perform a carbon monoxide test that another HVAC tech suggested. If this test shows no problem, does that indicate our furnace is safe? Were the explosions simply lint? Please advise.

One more thing- we were having problems with the pilot blowing out. I was relighting it every few hours. I've read that this too can be the result of a cracked heat exchanger. Hubby adjusted the pilot flame and no more problems. He says because we have a downdraft, it can blow the pilot out. A coincidence???? or more trouble???

Thanks,
A Scared Mom

[HayZee518]

If wind is getting down the chimney to the burner it WILL blow out the pilot! The chimney or stack needs to be high enough to create a draft. Try putting a chimney cap over the chimney. Because heat rises naturally you might try adjusting the draft controller so that some heat does go up the chimney to create the draft.

[Liceaga]

Thanks HayZee518! Any thoughts on whether we really do need a new furnace or not? Hubby performed the carbon monoside test (not sure what that involved but HVAC tech told him what to do) and says everything was fine. I'm worried about these mini-explosions too. We're in Michigan and can't stay at grandma's forever so- need to make a decision pretty quickly.

[Hube]

Liceaga. Since you say the unit is 20 or more years old, you may just be wise at this point and get 2 or 3 estimates on an new unit.
This way you will not have to sink any more $$$ into this worn out, badly maintained one.
And, by doing this, you will also gain some safety and some well deserved peace of mind. Your baby's will thank you too Good luck, Hube

[kactuskid]

Lennox pulse furnace models G14 were known to have cracked heat exchangers. Here's a link to explain all about them

http://www.inspect-ny.com/heat/lennox1.htm

But, you could very well have a problem, esecially with a 20 year old furnance that has obviously not been maintained. Dirt and dust passing through a filter and into the heat exchanger can be bad news. If the tech told you not to run it and you don't wanna believe him, then get another tech from a different company in there to take a look, one that deals with lennox products. It's not worth risking your life over.

[Liceaga]

Thanks Hube and Kactuskid. We've decided to get a new furnace. The initial hesitation was because we want to build a larger home within the next 5 years and are told we won't be able to use the furnace in it. Tech. said getting a larger furnace than our current house needs could cause problems with the furnace later. It stinks to spend the money and know we won't be able to transfer it to the new house but... I need the piece of mind!

[imeduc]

Dont try and put to big of furnace in the home so you can use it in another home later on. It just dont work thay way.

ED

My mistakes dont define me they inform me.

[heatmon]

Would someone really remove a furnace from a home they used to live in to put it into a new home? I've never heard of this. And by the way, a Lennox G12 could be almost 40 years old, manufactured in the late 60's and early 70's. I would've taken the tech's advice right away- definitely sounded like a cracked heat exchanger (re-lighting the pilot every couple of hours). Carbon monoxide detectors are of all different types of designs and must be installed exactly as the manufacturer set forth. Some must be on the ceiling, some on the upper wall and some must be located at mid wall height. If not installed exactly as it's manufacturer advises, either false readings or worse yet, no readings, can occur. I have seen with my own eyes, furnaces with cracked heat exchangers- holes big enough to put my fist through (and I have very big hands) without the carbon monoxide detector sounding an alarm (because they were not installed to their manufacturers guidelines). In one house the carbon monixide detector was "chirping" and the homeowner thought it was a smoke detector in need of a new battery. The heat exchanger looked like swiss cheese. One technician, sent to them by their insurance company told them their was "no problem" which led the insurance company to tell them to disregard any nuisance sounds from any of their home alarms. Get this- a young inexperienced service person tells them and their insurance company (who sent him) there's no problem. His boss sends out an estimate to replace the entire system (furnace-a/c coil-outdoor condenser)so an insurance company tells the homeowner to disregard any nuisance alarm tomes? I don't get it. Don't we value our lives, especially our childrens lives? If a service technician tells you something you feel is not right, get another opinion. Call your fuel (Nat GasOilPropane) supplier and tell them you'd like them to inspect for a cracked heat exchanger, there's a possibility of carbon monoxide poisoning in your home. They should come out to inspect, right away, with the proper testing monitors-sniffers. They can tell you immediately if you're in danger, but don't take chances with your life, your childrens lives.

This is just my opinion, and with it and a dollar, you can get a cup of coffee in most places.

[SSN596]

Testing for heat exchanger leaks requires a sophisticated detector. You CANNOT do this test simply using a CO alarm.