Digging a Hole Where the Furnace Gets In

Kindly forgive the Beatles song stretch. Today is a brief post covering a considerable amount of sweat and effort: getting the furnace moved into the crawlspace.

Can You Dig It?

dig hole

In my last post, we cut a hole in the old kitchen floor just inside the door to the garage. The hole is one floor joist wide, allowing the most narrow dimension of the furnace (~11cm or just over 14inches) to pass through. We decided that the height (depth?) of the other side of the hole would be the largest of the 2 remaining dimensions of the furnace. We could have used the next-smallest. We figured that whichever dimension remained would need to be available between the bottom of the floor joist and the ground. Since the plastic-sheet covered dirt floor was 2 feet (60cm) +/- from the bottom of the joist, we would need to dig. The furnace has one side that's about 28-1/2 inches (72cm) and it stands 33-1/2 (85cm) tall in it's original alignment. Our choice was to dig down 4 inches or so for the size of the hole or dig down almost a foot (25cm plus wiggle room). I suppose the mount of dirt to move is the same, its just a question of depth versus width. Still, it just seemed like digging shallow and wide felt like less dirt.

With the hole cut in the floor, I grabbed a 5 gallon bucket and the post-hole digger. I filled a bucket, hauled it up and outside and spread the dirt around a low spot on our lawn. I did that at least a dozen times. Once the main rectangle was dug, I considered that once the furnace was in the hole, we needed to tip it one way or the other to get it flat so it could slide around. So, the edge of the rectangle that faced towards the furnace final destination was cut down on an angle so we could pull that bottom edge up and away from the hole. I figured that if I had 28 inches from the bottom of the hole to the top of the dirt as measured from the inner edge of that floor joist, it could effectively hinge. By the nature of how this tip, though, that front edge will come up between the joists and not have an issue. It wasn't until after completing the dig, that I pieced that together and determined that I dug out more than I needed to. Ultimately, it is better to have too much room than not enough.

Venting Some Venting

venting set aside

With direct access into the crawlspace, Boo and I looked towards the location where the furnace would ultimately reside. Our view was impeded by supply venting routed all over. There are 2 main runs, heading in opposite directions: one towards the hole we just dug and the other going away. From these main trunk vents, the smaller round vents are attached. Where the 2 main runs come together is a large box (plenum?) where the conditioned air leaves the furnace and enters the system. All of this stuff needed to get shifted out of the way before we could bring the furnace down.

We started with the vent that ran from the box towards the hole. This system is old, and held together mostly by faith and tape. Boo removed the tape at the box, and the vent detached easily. She cut down the cloth webbing that suspended the vent from the floor joists and the whole thing dropped to the floor. She slid it to the side. I followed suit, removing the vent running the other way by the same steps. This left the big box.

the box

The box was simply hung from the floor by a lip that was less than 1/2". I lifted the edge of the lip with a bladed screwdriver, pressing the lip up and inward while sliding the screwdriver along the edge. The lip simply folded under the floor. Once the final side of the box's lip was so treated, the box fell to the floor of the crawlspace. I was (and still am) amazed that a heat system constructed in the late 1940's was held together without any fasteners. I removed the connectors attached to the box that allowed the vents to connect and then lifted the box out through the hole.

Sooty

blocked with soot

The last thing I tried to complete before lowering the furnace was removing all the soot from the clear-out. I foolishly thought that I could dig out the soot that was at the clear out down in the crawlspace. Well, it looked like the clear out had maybe never been cleared out. I was able to remove a full trashbag of soot and was unable to reach any further up into the chimney. Looking down from above (through the original oil? wood? coal? furnace-to-chimney access, I could tell there was at least another foot of solid soot I could not reach. So, Boo and I decided that we would bring in a professional. Many years ago, I had used British Brush to clean and repair chimneys at various houses. Well, they are out of business so we hit Yelp / the Yellow pages and solicited bids. In the end, we have some chimney repair from when the furnace was in the dining room, probably a new liner from the cap to the clear-out and then a safe connection to which we can attach the furnace. My biggest concern about this whole furnace move was to safely manage the exhaust and not accidentally create a CO or CO2 issue inside the house. Having a professional will help.

This is where we are left off. We have the venting removed, the furnace freed, an access hatch built and the hole dug for moving the furnace. We decided to leave everything just like this until after the chimney folks do their thing so they have the greatest mobility. We have some family events coming up, so the work needed to come to a stand-still anyway. We will pick this up after that.

As always, thanks for following along-

Kitchen Trap Door

In my last few posts, I have been walking through the slow process of kitchen and furnace demo. Today, our destruction continues with the creation of a hole in the kitchen floor, which will become a crawlspace access. Let's start with the obvious questions: why, how large and where. Before I begin, for my US readers, Happy first day after Labor Day; so starts the most productive period of the year (until ThanksGiving in late November). If you feel like you're working "so much more than", that's because you are. Now, where were we? Oh, yeah, cutting a hole.

Why

its a hole

Recall, this is a 1948 farmhouse. This house pre-dates most modern design like an inside access to the crawlspace. Instead, there are large openings around the outside of the foundation, which are blocked off with framed wire rectangles (to keep critters out). So, when under-house maintenance is needed, one of the frames is pulled off the house and the worker-person crawls under. When it is nice outside, this is clumsy, but not terrible. Add in rain, snow, cold and/or wind and this quickly becomes much less pleasant. Consider, between readying tools and parts in the rain near the crawlspace access, you will be fairly wet before you slide under the house... into the dry dust and dirt. Being wet, that dust and dirt clings to you. Yeay. Having an ongoing internal access would address this, but honestly, if a furnace could fit through the existing foundation opening, we would not have taken on the scope increase. Whether we were to buy a new electric furnace or reuse our existing furnace, the hole is too small to fit a furnace that is large enough for the home size.

How Large

So, answering the question "why" above, I shift to "where", with an eye on "how big". I took measurements of the in-hand gas furnace, and I swear the designer had standard US housing standards in mind when they considered the size. The most narrow side is just over 14 inches wide. Standard framing width is 16 inches-on-center, so the just over 14 inches wide will just slide between. The floor joists in this house are standard width (I was shocked, honestly), so the furnace can fit between. The next most-narrow side is around 27 inches. This is important for install as well, but this next-shortest side drove us to the size and shape of the hole. In short, the hole needs to be at least 14 inches by 27 for the furnace to slide through.

Where

stripped clean

I touched on where we were thinking about putting the access in my last post. Since we have not fully decided where things would go in the kitchen, cabinets and appliances -wise, we had to make some informed guesses. We recognize that the smart place to put food storage (fridge and pantry) is close to the door where you bring groceries into the house. So, we figured the if we set the trapdoor inside the door to the garage, the limit to how far into the room it can go will be constrained by the space consumed by food storage. Knowing the width of the pantry (sitting in the garage, waiting for install) is 24 inches and a standard-sized US fridge is 33 inches, we can measure off the not-moving-chimney towards the door to the garage, and mark where the closest edge of the fridge will be.

Along the adjacent wall (the wall with the door in/out of the garage), we intend to put cabinets with a sink. Similar to the pantry cabinet, we know the width of that standard-depth cabinet (82 inches). By marking that off on the floor, we could see that there was about a foot and a half between the end of the cabinet and the start of the door frame, leaving ample space for garbage/recycling bins by the door. For this purpose, though, it gave us a large space where the hole could go.

With these parameters, we needed to know where the joists and beams were so we could cut a hole that met the various needs. To get exact locations, someone had to go under the floor.

Mark Your Spots

old access

Boo has a very healthy sensitivity to rodent waste and what the dust that waste creates can do to your lungs. Because of that healthy sensitivity, she has always taken on the role of under-house-slider, wearing a full respirator. For this task, it was no different. She took a flashlight, a measuring tape and a cordless drill with her. Shouting to each other through the floor to arrive at an approximate location, Boo sent the drill through 6 different locations to indicate for us where the joists were. Beyond the drilling the holes, Boo had a clear understanding of what barriers or hurdles exists beyond the joists. It was with that info plus the drilled holes we were able to plan the rectangular cut.

Cut Once.... Or Twice

Based off of the holes, we drew an initial rectangle. I opened up the holes with a larger bit so the jigsaw would fit and then cut the lines. Once we had the initial hole, Boo and I got to thinking, did some more measuring and more talking. It was at this point that we realized that the furnace could fit between the joists. Could we have figured this out earlier? Maybe. Sometimes, you need to see things in real-time before you have a flash of realization. Once we could see where the cabinets and fridge were going, we could see where we could re-shape the hole parallel to the door to the garage. The furnace would fit and we would not have to cut and frame-fix any joists. So, we measured and cut another small section of flooring out, reshaping the hole.

Furnace Prep

While this was going on, I removed all the bits that were attached around the furnace, to get it's dimensions down to the size of the outer frame. This included removing the stove-stack out the top, the gas line from the side and the emergency electric shut off box. With these gone, the furnace is actually the measured dimensions, allowing it to pass between the joists. In my last post, I walked through our logic to try to reuse our in-hand furnace. We are continuing with that thinking, as you have probably surmised from how we approached the size of the hole. While Boo was under the house, she crawled over to the chimney and confirmed there is a soot clean-out. So, with that variable solved, we could commit to reusing the furnace whole hog.

A hole in the floor just inside a regularly used door is very unsafe. As you can see in the first image, we temporarily covered the hole with some waste from the first cut. Once the furnace is through the hole, we will nail-down some plywood until the flooring company can fit us into their schedule. At least the visible floor in the kitchen is getting replaced; we don't know about the rest of it. Regardless, this trapdoor will persist, and while the extra cut will create some subfloor repair by the flooring company, this access will be an incredible upgrade long-term while creating a means of moving the furnace where we want it. That's next.... and a future post.

Thanks, as always, for following along-

Furnace Freed

Continuing the NewOld House construction, today's post is about disconnecting the furnace, and considering our options for what's next.

Hapy Update

I know I have not written much about cars lately, so here's a quick update on Hapy. I don't drive every day, but Hapy has been my main vehicle all summer. The other night, I grew frustrated with someone driving at least 10 mph below the speed limit in the left lane. I was cruising around 2k RPM in 3rd (around 30mph in a 45mph zone). An opening appeared in the right lane, so I stepped on it and started changing lanes. I guess I stepped on it too hard because I smoked the tires for a second before they grabbed, launching us forward. Goes to show, the KermaTDI bigger nozzles and Malone Tuning CPU chip were significant improvements. Since I have been driving him so much, it is now time to do his front brakes. I am still questioning the brake booster, so once the front brakes are done, I may revisit the booster and master cylinder. Since Hapy has become the gear-hauler for the band I've been playing in, taking him off the road has larger implications than ever. Anyway, back to the furnace.

Exhaust

furnace freed

Because of the way the furnace was installed, I had to get the exhaust stack out of the way first. The furnace is not a 95% efficiency-or-better, so the exhaust is both double-walled and transfers more than just water vapor. Still, it is put together the same as one of the high efficiency ones, it is just double walled instead of single. Some pieces twist-lock together and others are held together with sheet metal screws. With a 1/4" hex socket on the cordless torque driver, I made quick work of all of the sheet metal screws. I was able to remove the exhaust in sections and set them aside. Once the entire exhaust, from furnace-to-chimney-liner was removed, I shifted to the cold air intake or "return" in HVAC parlance.

Cold Air Intake

On this furnace install, the cold air return/intake enters from above. So, while warm air rises and cold air drops, our cold air return was installed 6 feet up into the wall. Genius. It was simple to take apart, though. The protective grill was held on with 3" long screws, which also held the air filter in place. Behind that the HVAC flashing was bent to create a flute or trumpet-bell shape to route air from the grill through the hole in the wall into the main intake. From there, the intake took a 90* turn down into the top of the furnace. Easy-peasy. The intake was similarly held together with sheet metal screws, and it came apart just as easily as the exhaust had. The sole difference was that each seam had the fancy shiny duct tape. That came off fast too. Once in pieces and the trumpet-bell bits bent straight, the whole unit came free.

Hot Side

exhaust removed

Once the "cold" air passes into the furnace, the squirrel-cage blower pushes it through the heating element and down into the chase below. In our case, that chase is large, rectangular and takes an immediate hard 90* turn along the main beam. From that chase, the round insulated heat conduits attach, routing the air to the various registers around the house. None of that needed to be touched for the furnace removal. All I needed to do was detach the furnace from the floor. Again, sheet metal screws held a double-thick 90* bend of HVAC flashing between the side of the furnace and the top of the chase interface. Once removed, the furnace was free-floating. We intend to re-use as much of the original "hot side" as we can. The round insulated tube things were all replaced when the crawlspace was done, so they are effectively new. The places where heat needs to go remains the same and whichever furnace we put in the crawlspace, it can send heat (or should I say processed air) down the same paths.

Electric

Next came the electric stuff. I started by removing the thermostat and the trigger cable from it to the furnace. We don't know if we are going to retain that thermostat, nor are we sure it is going back in the same spot. Either way, it was a standard 5-wire control cable, so re-installing it or doing net-new is very little difference in cost. Having it all out so we could make decisions was worth the few minutes.

Obviously, a gas furnace still needs electricity to run the squirrel-cage fan, so I flipped the breaker for the furnace and disconnected it at the furnace end. I pushed the wire through the hole in the floor. Next, I disconnected the ground wire which the prior installer had connected to the gas line. While I would like to accept that this was safe, it really didn't feel like it. I think we will run a fresh 3-wire line if we reuse this furnace. Since an electric furnace requires 220V, that would also get a new line.

Gas

gas and electric shutoffs

All that remained was the gas line. After our little excitement a few years ago when Zed went crashing into our gas water heater at the old house (See One of the Many Joys of Home Ownership), I was not exactly wanting to do this part. Our pipe-fitter (also licensed plumber) friend offered to do it. So, Lana came by, shut off the gas at the meter, disconnected the gas line under the house where it bent up to the furnace and capped it off. Together we push/pulled the disconnected end up through the hole in the floor, leaving the furnace completely disconnected.

Considerations

We have a curious cat, so we are leaving the furnace pretty much where it was while we figure things out. Otherwise, we would have a cat stuck in the heat system as fast as you can ask "where'd the cat go". Meanwhile we have some things to figure out. The furnace was manufactured in August 2019. The house was vacated around a year later, so the folks who installed the furnace got one winter out of it. We bought the place last year and used it this past winter so this furnace has 2 years of use. There are at least 15 more in it. Knowing that natural gas prices will continue to climb, eventually this furnace will be more expensive to run on a month-to-month basis than an electrical one, but that isn't the case today. Today, a gas furnace is considerably less expensive to run. A heat pump is different, but we don't have one of those. Adding a heat pump to this system would be a $8-10k upgrade. We are not in a financial place to do that. Assuming either system can reuse the existing hot side, and routing the cold return from the hole in the floor will be effectively the same, we can eliminate those from the decision: its a wash.

August 2019

So, we are looking at electric-only or gas-only. Since this furnace is practically brand new, and in-hand, it probably makes the best financial sense to keep it, and install it under the house. Before we jump in, we need to route the gas and the exhaust -or- get 220V under there and set up the trigger cable. The gas is already right there. We may need to add some flex-pipe depending on where the furnace ends up, but the gas part seems easy. For 220V, we have multiple extra slots in the breaker panel, so it would just be a matter of adding a breaker and threading the wire through. I know how this furnace was set up so re-introducing the trigger wire is easy. I don't know anything about a new furnace, so while it is probably not that hard, it would be something new and potentially challenging. Last, the gas furnace needs to have the exhaust routed. The chimney goes through the floor, but we don't know if there is a clean-out at the bottom. That would tell us if the chimney is hollow below the floor (we think it is), and therefore available for having the exhaust run into it. This mystery needs to be resolved if we are going to retain the gas furnace for a few years. I think, for the bigger financial picture, it makes sense to relocate this furnace rather than spend even $1500US on an electric one. I cannot imagine routing the exhaust would cost half that, and the 220V routing versus gas routing is a cost-wash. So, really it comes down to the cost of the exhaust versus the cost of a new furnace plus the increase in monthly cost to run the electric... even if we could sell the gas furnace to offset some of the initial outlay. I think, the gas makes better cost-sense. Once we make a determination about the chimney, we'll know.

Well, that's it for now. thanks, as always, for following along-