Cracked heat exchanger?
I have my HVAC system serviced/inspected 2x/year. The unit was installed in our spec home in 8/02. We purchased the house 4/03. Two years ago (fall 2010), the tech did a puff or smoke test where he introduced smoke into the heat exchanger and watched it swirl around and slowly drift back out. With that test, he said I had a cracked heat exchanger. He told me he would have to shut off the gas and replace it. He had the HVAC company owner come out and re-do the test. The boss said, no there was no crack. Last year, they did the same test and and found no problem.
Yesterday there was a new tech. He did the same test, said the heat exchanger was cracked, and shut off the gas and tagged it out. Options were to replace the heat exchanger or replace the furnace. He also threw out that we should replace the AC since we have a documented refrigerant leak. Of course, he pushed that we needed to make a decision ASAP so that they could fit us in their schedule so that we wouldn't be without heat as the nights are getting colder.
I had the tech come back last night and walk through what he found and what he recommended with with my husband. Meanwhile, I researched my York Furnace and found that I have a lifetime warranty on my heat exchanger. When I asked about that, the tech wouldn't give me a straight answer. I wanted to know what the labor charges would be to replace the warrantied heat exchanger. He finally said someone would call me in the morning.
I also made arrangements for another HVAC company to come check out my heat exchanger. I chose a company that is a York dealer since I felt they would be most familiar with our unit. He arrived this morning. He turned the gas back on and checked out our heat exchanger. He used a CO detector and found no elevated levels of CO. Based upon his visual inspection and the test he said the heat exchanger was not cracked.
1. While I've read about smoke bombs, I hadn't found much about puff (smoke) tests. Is this a valid test? Anyone have a video on what this test should look like?
2. Are there any other tests besides the CO detector that should be done?
3. We have CO monitors in the house, but they are ceiling mounted. Someone told me they should be placed low. Is that correct?
4. Any questions I should be asking either contractor regarding my system?
BTW, the first contractor has not contacted me today at all. Not certain why. I thought they wanted a sale.
If you have any other information or web resources to share I would appreciate it.