Newer furnaces have a tap on the circuit board that energizes only with heating calls. Just hooking up to a blower tap or unused blower speed wire will still cause it to come on when ever the blower is energized. There are current sensing relays available that can be installed on the heating speed wire to blower to activate when it senses electric on that leg, such as the Aprilaire #50.

Hello Mr. HVAC (a name that sounds like the Grand Puba of HVAC) I am sure I have more stupid stories than you could imagine also; Just not me. If I need to put equipment on a roof, I hire a crane. Done it, been there. I have to admit, I have the training to be a rocket scientist, I lived in Houston for many years, where rocket scientists exist in great quantities, but I work on practical equipment. I attended the same engineering college that produces many scientific workers at NASA. I have performed muck level jobs, I love the smell of oil and grease. I also design and build devices. I know how to read technical data; which seems to be a problem with many HVAC workers in Texas. I tried to discuss technical aspects with this forum multiple times, but you werent interested. I was willing to try. The best you could offer was comments on my alleged drug usage. Kinda lame in my opinion. I guess you fall into the reading challenged category. You have been working like a pack mule longer than I have worked with HVAC, from your admissions. I wouldn't want to brag. When I need manual labor, I hire workers ALWAYS. If I need to do a labor intensive job in an emergency, I still hire workers. I have hired temp workers walking by a job at midnight and put them to work immediately. I think like a boss, not a worker in that aspect. I guess that comes from many years of operating my own business. Think smart, try to never repeat mistakes, and NEVER lie to the customer. I still think that if I can teach you, I can teach anyone. You are an opinionated hard case that is living in your dreams. I hope you are happy; I have dropped to your level with this post. As to advising on issues, if I do not have direct experience; I don't advise. It must be mind boggling to you, to imagine my qualified experience level in so many areas. As a service provider/ owner, I did a lot of varied work. Just because you donÂt agree with me does not immediately make me wrong. It does show poor judgment on your part, to claim I am wrong. For the people that write me, or are considering writing me; I am always willing to help, but I do not feel it is appropriate to troll this site for work. If I give referrals to anything, I do not profit from the referral. IMO, this is bad business. Others can do as they wish. When I started posting on this site, it was not for any ego gratification. It was to show potential employers my troubleshooting skills and general knowledge. I found that I like helping people in need. I mention this site (Garden Web) to all that can benefit. I do not post very much on the other site, that has a lot of commercial and large equipment workers. I do post where appropriate. Funny I donÂt get negative comments on that site. Only pros are allowed. I would probably stop posting entirely on that site if some of the guys were like this site. I have asked the same questions, and of skill level there also.

Whoa, that's really ugly. Here's a true story for you. Several years ago I walked down into the cellar one evening and heard an odd humming noise. After some investigation I found that some of our old original rubber-and-cloth knob and tube wiring had been run over, into, and through a cold air return duct. The wires were unsupported and had no protection at all where they passed through the sheet metal, no ceramic tubes, not even loom. This must have been done when the heating system was upgraded and the cold air return was installed, probably between 10 and 25 years earlier, before I owned the house. Over the years, the duct's vibration had worn the insulation from the wires where they touched the sheet metal. They also had sagged so they were touching the top of the duct (probably the reason for the humming). Fortunately, the copper actually touching the duct was the grounded (neutral) conductor. But the hot side wasn't far behind. If I hadn't found that, we might have had a fire or electrocution. So, no, what you have there isn't right; and yes, it's hazardous. I think (I'm sure Ron will correct me if I'm wrong) that it's still permissible to route NM cable through a cold air return if it's protected by thinwall conduit or something equivalent. But IMO it's best to avoid it entirely if you can. In general any wiring of any type (including low voltage and phone and data cable) that passes through an air handling space is supposed to be "plenum rated." IIRC, that has to do with its flame resistance and smoke production when heated. Please get that fixed.

This is veering a little off topic. Nitpicking? I've called it that. Is this the only thing the inspector flagged? If so, they had to find something or the customer might think that they are not doing anything. If there is nothing serious to cite, they will find something because no old house if perfect. I am involved right now in the sale of a 57 year old house in central New York. The inspector found a moist spot on the main water shut off in the basement, and the microwave did not work. We knew about the latter, but a surge took it out after we did the initial paperwork for the sale and we forgot to add it to the disclosure. We gave the purchaser a credit for the MW and had a plumber install a new shut-off. If a second inspector comes in, they will find a couple more equally serious problems. We can only hope that any inspector will find the serious problems if there are any.