Each year, I try to make it until about Halloween before I turn on the furnace. This year, we had one of the coldest Octobers on record. As luck would have it, I still managed to make it past Halloween before using the furnace.

Around October 20th, I got really sick. And it got pretty cold outside. I wanted to have it nice and cozy warm inside, so I decided to turn on the furnace. I set the thermostat to “heat” and turned it up so that the furnace would kick on. The draft inducer motor kicked on and I went about my business. A few minutes later I noticed that the main blower still hadn’t kicked on. Further testing revealed that the draft inducer was kicking on, but I wasn’t hearing the “sparking” noise that the pilot ignition normally makes, the pilot wasn’t getting lit, and I wasn’t getting any heat. The furnace is down in my crawl space, and I wasn’t in the mood to crawl around under the house at the time, so I got out my little portable Titan heater and used it to get me through the sick spell.

When I got to feeling better, I made it down below the house and started doing some debugging. There’s a box on the outside of the furnace that has a spark plug-type connection on it that goes to the pilot light area. So, this box seemed like a logical place to start looking. I later discerned that this box is the Intermittent Pilot (IP) control. The IP has the spark plug wire, and it also has wires going to the gas valve that control when the furnace should send gas to the pilot, and the main burners. Applying a match to the pilot area still didn’t result in the pilot actually lighting, so this indicated that the IP unit wasn’t instructing the gas control to send the gas to the pilot area.

So.. it seemed likely that the IP box was having problems. I started looking around. I had a Honeywell S86H Intermittent Pilot, and I found one on eBay that was brand new, but out of the manufacturer’s guarantee period. I didn’t really care about that, so I bid on the unit and ended up getting it for $55. New it would have cost me probably $150 or so. So, it was a gamble. If that ended up being the problem, I’d save a fair amount of money and have the satisfaction of knowing I’d fixed it myself. If not.. I’m out some cash.

Won the bidding on Wednesday. Had the part on Friday and replaced the box that night. No difference. So, it was a gamble, and I lost. Time to call in the professional.

I had an A/C compressor replaced a few years back by a guy (Mike Duecker), and I was pleased with the job that he had done. So, I called him up on Monday and set up an appointment for Monday afternoon. Mike and Jim, his coworker, showed up Monday afternoon and, after some exploration, determined that the pressure switch wasn’t telling the IP unit to start the ignition process. Normally the draft inducer motor kicks on causing a certain amount of pressure, which is detected by the pressure switch. The pressure switch then tells the IP that the pressure is “OK” and the process continues.

So, they called up the local supply store, and the store didn’t have any of the particular pressure switches in stock that my furnace needed. So, he left, saying that he’d know something in 20 minutes, or an hour and 20 minutes, depending on which store he needed to go to. I got a call about 30 minutes later. The place he was at didn’t have the part, and it would be 40 minutes for him to get to the other store. I told him I wasn’t in a hurry, and the place could order it and have it the next day, so we decided that I would meet him on Tuesday morning at 10am.

Tuesday morning. Mike and Jim arrived with boxes. We got down to the furnace and Mike started looking around. He unscrewed the chimney leading away from the draft inducer and the furnace started working as it should have. This meant that the pressure switch was actually working as it should. The draft inducer wasn’t able to force the air up the chimney with enough force cause the pressure to be what it needed to be. Which meant that the chimney was somehow blocked. The part of the chimney leading away from the furnace was made out of doubled walled 4 inch pipe as it should have been. But, when it went from horizontal to vertical they switched it to 3 inch single walled pipe for the trip to the roof. This was causing the gas inside the pipe to cool more quickly than it should, which was causing the water in the gas to condense on the inside walls of the chimney pipe, which was causing rusting and mineral deposits to show up at any joint on the chimney pipe. I had noticed this for some time, but hadn’t thought much about it.

So, the chimney had code problems because of that, and it also didn’t have the necessary slope if it were to simply be replaced. It was touching the wood where it was supposed to have an inch of clearance, and didn’t quite have 6 inches of clearance where single walled (but it shouldn’t have been single walled anyway).

So, the chimney needed work.

Mike then got out a little mirror on the end of a stick and looked around at the heat exchanger in the furnace. Cracks were found. This is a bad thing because it lets gas escape from the heating chamber or, more likely based on where the cracks were at in my case, it would allow gas to enter the heating chamber, causing other types of problems.

The furnace is 17 years old, which puts it at the end of its useful life. So the options were: stay with the existing furnace, and fix the chimney. This would cost a few hundred dollars to do it right, and the crack would still be in the heat exchanger. Replace the furnace with an 80% efficient furnace and still fix the chimney. Or, replace the furnace with a 90%+ efficient furnace and run PVC pipe for the chimney. Either of the last two options would be similar in cost.

So, I went with the 90% option. Mike said that they would pick the furnace up Tuesday afternoon and be there at 8:30 am on Wednesday to put it in.

Wednesday morning rolled around, and they arrived about 8:40. They started dismantling the old furnace while I cleaned up some in the crawl space. Previous tenants have left all kinds of strange things down in the crawlspace. There was an old heat exchanger down there, and there are probably 30 or 40 old furnace filters, along with boards, random pieces of cable and wire, old baskets.. You name it.

I hauled the old heat exchanger out of the crawl space. It was quite heavy. Mike and Jim said they would haul it away with the rest of the stuff. Their truck was in the shop, so they actually didn’t bring the new furnace. or have what they needed to haul away the old stuff. Getting the old furnace out of the crawl space opening was more of a trick. It couldn’t have been any larger and still have fit through the opening. In fact, the ductwork going to the utility room vent had to be dismantled and shoved aside so that it would fit as is. Once the furnace and all of the old pieces were moved outside, Mike and Jim left. This was about 10:15 in the morning, and they said that that their truck was supposed to be fixed by noon, and that they would be back in the afternoon. The afternoon came and went. They didn’t show. They didn’t call. Not real pleased, but the guy seems to do good work, and his prices are reasonable, so I cut them a little bit of slack. Seems rather unprofessional to not at least call and say that he can’t make it.

Thursday morning I got up and went to work. I got a call from him at 9:13. Everything was a “go”. I told him I was at work and he said he’d do another job and call me 2pm-ish and then come over and get things put in. He called about 3:15. Said that he had to get up on a roof and that he could be by my place around 5. So, I was home at 5, and he knocked on the door shortly thereafter. He was worried about the entrance to the crawl space. It isn’t any too big for the furnace unit, which is a Ducane CMPB075C3. We measured the opening a couple of times and determined that we could take the support boards off the crawl space entrance and dig down several inches into the dirt floor and get the furnace in. We then set up a time on Saturday morning that they will be back to take care of the installation. They carried off the smaller pieces of the old furnace and planned to get the remainder on Saturday.

Saturday morning arrived, and I took a quick trip to the local rental place to rent a power auger for the sewer line thanks to another household crisis. I got back and cleaned out the sewer line. Mike and Jim weren’t yet there, so I went ahead and took the support boards off the crawlspace entrance and moved a small amount of dirt with the shovel when Mike and Jim arrived. They started digging on the hole. At one end of the hole it was about 25 inches to the dirt. On the other end it was closer to 30-35. The furnace was 46 inches long, so one end had to be dug down almost 2 feet. This dirt hadn’t had any moisture in it in probably 50 years. It was very very solid. The digging literally took until about 12:30pm. We had been using the furnace box to determine if the furnace itself would fit. We made it to a point where the box fit, and then the furnace went down into the crawl space. Mike and Jim carried the furnace over to its final resting spot and I put some of the support boards back onto the entrance of the crawl space.

We then ate lunch (Domino’s Pizza). Jim started working on moving the gas line (the new furnace was pointing the other direction, so the gas line had to be moved over. Mike started working on duct work to attach the air conditioning coil to the new furnace. Both of these operations took a while (hours). By about 6pm, the gas was operational and one end of the duct work was attached to the furnace. Hours of work remained. They left. Mike would be back in the morning before I left for church.

At 9:25 Mike showed up. When I got back at about 12:10, the furnace was running, but things weren’t done. He had wired the furnace to the electrical, put in pvc chimney pipe, routed it out the side of the house, put in the condensate tubing, and had just started the furnace for the first time. The other half of the duct work wasn’t yet connected. The first time that the furnace was started it had to burn off the coating of “stuff” that was on the internal parts, so it did a bit of smoking. The smoke detectors went off for a while. There was also a minor issue with the inducer motor. When I got there, the furnace was running, but with a high pitched whine. He took a few things apart and restarted the furnace and it was much quieter. He went to work on the final piece of duct work, and I let the furnace run for a while. Opened some windows and ran a fan for a while to get rid of the smoky haze in the house. It didn’t take very long.

The new furnace was putting out a fair amount of heat. It’s something how warm and comfy a furnace can make a house feel, versus a little portable heater. The heat is so much more homogeneous.

The final piece of duct was put in, the tools were cleaned up, the bill was paid, and the old furnace and even older heat exchanger were put in the back of his truck, and he was on his way. This was about 3-3:30pm.

Post Mortem:

It took a while for things to get taken care of. When they came on Monday, they could have correctly diagnosed the problem as being a blocked chimney instead of a faulty pressure switch, and they could have looked more closely at the heat exchanger to see if it had problems.

On Wednesday, they said that they would be back after lunch to put the new furnace in. Them not showing up at all was a big strike.

When we set up a time for Thursday, I assumed they would at least do a little bit of work while there. Had I known they weren’t going to do anything I might have been able to not bother rushing home like I did.

I bought the pizza on Saturday. No big deal there, in and of itself.

They carried off my old heat exchanger for me. That was nice of them.

On the bill, they charged me $1,750 for the furnace install, and then they pinged me $75 for a service call. That seemed a bit nickel-and-diming after they were getting close to $2k for the new furnace.

They seem to do good work. They seem to care about what they are doing, and I trust that they know what they are talking about.

They seemed flexible on the options. They would have been willing to run the new chimney out the roof of the house, or out the side. I chose to have it run out the side. I’m planning on putting on a new layer of shingles next spring, and I’ll totally get rid of that hole in the roof when I do so.

Interesting facts: About 25% of the furnaces he works on are in crawl spaces. He puts in about 99+% Ducane. They do zero advertising, so you don’t have to pay that premium, and he said he’s had really good luck with them. He puts in a lot more 80% efficient units than 90. He said that there is a few hundred dollars of difference. I have a 75,000 btu unit. He said that 100,000 btu unit would only add about $50.

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