The coal bin was gone and a lot of junk had left the building, but I still had a lot more cleanup to do. The basement still smelled like mold to some degree, and there were several more areas that hadn't been touched in twenty-plus years. Conversations between me and Synergy were beginning to work toward an actual agreement, including significant steps such as some initial "consulting" money changing hands and them coming by to measure all the relevant window and door openings. I found another HVAC guy who seemed to understand my needs; more on that later. With these promising developments and plenty still on my own preparatory to-do list, I had to tackle the rest of this and get it done. |
Dark shadows
The old roof shingles were a slightly unusual diagonal design, often called "hurricane" shingles with little tabs designed to lock the downward corners under the next row. I found a few spares that had never made it onto the roof. In theory I could have used these to replace a few bad ones up there, but at this point they were far enough gone that bending the old ones up to try and access the nails would have just snapped them off. To their credit, what was up there had lasted far longer than anyone could have expected. | |
Here we also see the now-completely-illegal unprotected oil feed pipe
running right into the slab on its way over to the furnace. Environmental
officials had dealt with enough leak issues in such setups and dug up
enough basement floors and contaminated soil underneath over the years
[at huge homeowner expense]
that most states had mandated that these either be re-run through leak-tight
enclosing "smurf" tubing, or moved overhead where any leak would be
immediately obvious and get fixed. That included existing installations;
there was no grandfathering of these and if it meant jackhammering a trench
across the basement floor, that's what they wanted everybody to do. Piping
up along the ceiling might be easier but often created problems with air
bubbles getting in and making oil pumps lose suction; that's exactly
why the
Tigerloop
de-aerator was invented.
At this point I could hardly believe that I had been seriously considering upgrading the rusty old oil tank to a Roth dual-wall and running new lines with a Tigerloop and staying with oil heat. Getting rid of this whole mess, especially when I hadn't done anything about the feed pipe a year and some after the effective date in Massachusetts, was another nice side-effect of deciding to kick the oil habit. |
Masonry chisels are awesome
Rot & roll
Interesting fungus rhizomes turned up on the decayed well-decoration parts as the layers got separated. |
Duct work
In addition to ACCA Manual J for calculating building heat/cool loads, there is also Manual D covering air-handling and ductwork design. This is a bit more important than most people think, as ducts that are too restrictive will greatly reduce the performance of an otherwise perfectly good HVAC system and cause occupant discomfort complaints. Air has a certain specific heat capacity, and if that's to be the medium to carry heat to or from a space then one must ensure that enough of it can reach the target area per unit time. Manual D is all about duct sizing [ahem, that's *duct* sizing] and CFM and static pressure, a certain portion of which can be summed up in this chart or a slide-rule type of tool called a "ductulator". There is also a bunch of info on how various bends, junctions, transitions and takeoffs affect airflow and that all has to be plowed into a proper duct design. | |
I don't even remember where I found this graphic, another crazy tangle of
logarithmic lines that does make sense once you study it for a bit, but
it's called an "air friction chart" and
gives a lot of information in one easy-to-read place. Most residential
designs land in the rectangle bounded by .06 to .6 inches of water and maybe
up to 2000 CFM, between the slightly heavier-looking horizontal lines
that presumably indicate a sort of sweet-spot area of static pressure.
Area conversions from round to rectangular ducts are left to the user,
but I quickly figured out that my 10 x 3 inch runouts are about
equivalent to six-inch round.
Some HVAC guys are outwardly leery of re-using an existing duct system for any changed heating/cooling plant, and encourage grinding through a full room-by-room Manual D which can often result in recommendations to replace a lot of ductwork. "See, the computer said so!" ... Cha-ching! But when a system is being *downsized*, as mine was about to be, one could easily argue that an existing set of ducts would be completely adequate as the overall airflow would be *less*. Undersized ducts are a common problem cause, but slightly oversized ones, especially when contained fully within the conditioned space as mine are, can perform perfectly well. I spent a little time angsting about whether my old ducts would be sufficient but after firming up the capacity math and noting that I'd be going from 1000 CFM to about 600 max at the blower thus almost halving the flow, I knew I'd be fine with it. My system has a slight advantage that was somewhat unusual back in the days when it was built. A traditional forced-air heating configuration ran the supply ducts out toward the exterior walls and tended to place registers under windows, in an effort to combat cold air sliding down off the crappy single panes of the time and minimize chilly drafts that people would feel. But the old system here has the supplies toward the inside, with the warmed air kept near the central core of the house for its short trip to the outlets and the *returns* placed on the exterior walls. The advantage in a better-insulated scenario is that the supply air doesn't lose as much heat into the surrounding basement before being delivered, and if the return air gets chilly on its way to the furnace it doesn't matter, it's going to get warmed up anyway. In many downsized systems with lower airflow, minimizing heat/cool loss in transit becomes a little more significant because the air stays in the duct longer. In systems with ducting run through unconditioned spaces such as attics, it's much more significant as a lot of energy can be lost even with insulated runs in good repair. Since my basement is part of the conditioned space anyway, it matters far less and thus my "duct loss" figure is zero.
|
Basement window rework
The first one to be thus tackled was the aforementioned rear window with the heavy sill rot. Basically the lower third of the whole thing was removed down to the cinderblock. The easiest way was to simply cut out the frame at the sides, my only real option for which was an old-school hand saw. Wooba, wooba, wooba. I don't actually own a Sawzall [yet] ... |
So here's how a basement window opening becomes a new section of wall:
the 2 layers of XPS get caulked in against the rails from outside and
then inside, my !expensive! and somewhat experimental slabs of battleship-gray
PVC slapped on as the outer cover [but with bug screen added around the
periphery, not yet attached to the piece shown here], and inside simply gets
thin plywood to be structural but provide
some amount of vapor permeability. Having PVC also on the inside would
have likely turned this into a "moisture sandwich", not what we want right
underneath the main sill. After everything was in, each outer frame also got
foamed in at the sides to better seal its junction to the masonry, with
the bug screen sort of embedded inside helping bridge the gap. I took that
lesson from Joe Lstiburek's
battle with the ants
and decided to proactively head off any possibility of insect intrusion
via something *I* had put together.
While I generally don't like painting, I decided to make all the frames grey since I had a big batch of latex "oops paint" left over from when we made some setpieces for a convention. The stuff even had Rosco flameproofing salts already mixed in. Eventually I even painted over the bright yellow spray-foam once it was all cured up and trimmed back a little. |
The bottom ends of the old side frames actually weren't totally rotten, but had to come out to fit the new sill piece anyways. Compare to the actual sill wood, which fragmented under a light touch. |
Basement window # 2 (first keeper)
Furnace decommissioning
At this point I had discovered that Daikin AC had a central
upright air-handler product
for their split-system heat pumps designed to go in the same place as
a typical furnace, and had found a clueful
local dealer who supplies
and installs them. Mitsubishi only had *rumors* of a similar product
about to possibly come out in April, but not only did Daikin have it
available already their units in general seemed to be as if not more so
favored for reliable high-efficiency installations. Daikin's original markets
were in Japan and Europe where residents have *much* more clue about lowering
energy consumption, and their latest inverter-driven designs had great
cold-ambient performance on par with Mitsu's vaunted "hyper-heat" system
that some other acquaintances had mentioned to me. There are several other
competitors in the same market -- Sanyo, LG, Fujitsu, etc -- and their
cheaper units all look almost exactly the same and just scream
"corporate-espionage copycatting". But reading the forums gave the
impression that attention to quality at the underpriced manufacturers
was considerably less than that of the original players.
The lowest system capacity on these Daikin ducted units seemed to weigh in at 18,000 btu/h, a ton and a half which was a bit more than I was thinking but I realized that a> that wasn't a problem with these systems and b> who knows, there might be some time when a little extra capacity might be useful. The ability of the inverter-drive compressors and ECM fans to turn themselves *way* down to match light loads at high efficiency without short-cycling gave a lot more leeway in the whole system-sizing problem. So now my magic number was the "18" embedded in the various component model numbers, and I could wander through Daikin's website myself and basically match up parts. Condenser, AHU, and thermostat/controller -- all linked up by a simple two-wire digital interface, exchanging a lot more useful information between all the pieces than a simple "hey, it's cold in here". And the HVAC dealer sounded enthusiastic about these systems, saying I couldn't do much better in terms of efficiency -- this guy also understands the need for radically smaller systems in tight houses and wasn't about to try and sell me a 3-ton monster. Having finally found a specific system I was confident about, I was even more eager to get the wheezy old oil furnace *out* of my life. The right time to do that came along only a few days later, and the interim had been just the right amount of time to play around with ducts and flow and some final reassuring calculations before starting to tear it all apart. |
To try and get the rest of it out, I wanted to try and tip the entire tank
a little. It was then that I discovered that the support legs were cemented
solidly *into* the floor. Fine, whatever. I hacksawed the two rear legs
clear right at floor level, which wasn't as much work as it seems because
the one toward the wall with all the efflorescence was
pretty corroded already, and jacked up the back end of the tank a bit in
an effort to let the remaining oil drain toward the outlet. [The
Mighty Screwdriver
makes another appearance!] This got a little more to dribble out but not
all of it; I couldn't jack too high because the fill
pipes were still firmly connected through the wall above and they and the
remaining legs were starting to bend oddly. I left it that way for a couple
of days with the jug underneath, and recovered maybe another quart.
The little screw jack was another legacy from the former owner, and was exactly the right thing to stick under here and start cranking on. I thought I'd never really use the thing, but had kept it around anyway. |
It's the build-your-own furnace kit! Some assembly required, bicycle
not included.
I wouldn't be needing these parts anymore, and offered them up on the local-homeowners group with a detailed list. Eventually a friend who's sticking with oil for a while longer came over to cherry-pick the potentially useful bits. |
_H* 120520