Advanced digital smart control of a... stone age technology swamp cooler?

Sure, why not?



This is just a breadboard prototype. The finished project will be mounted inside the wall in my hallway, with just the display and some buttons visible.

Swamp cooler: passed final inspection

Today marked the final inspection on the swamp cooler. Since I had to run a short duct from the swamp cooler through the attic to the living room ceiling, I had to pull a "mechanical" permit in my jurisdiction. That's a good thing: improperly sealed ductwork can cost you a lot of money on your heating/cooling bill, so it's nice to have another pair of eyes checking up on your HVAC contractors' (or lazy/cheap homeowners) work ethic. In my case, not only did my cute little baby duct pass, but Lemontree tells me the inspector liked what he saw. Aw, shucks.

Anyway, I learned a couple things. One, ductwork is not a science, it's an art. (And I am not an artist.) Two, mastic will cover many sins.

Mastic is this lovely gluey stuff that's approximately the consistency of sour cream. When dry, it provides an airtight yet flexible rubbery seal, since metal ducts expand and contract with temperature changes. Actually, most of my joints ended up pretty tight so it didn't take much mastic to seal them up. However the final joint just didn't line up quite right... even though I took great pains to use a plumb bob to transfer the roof duct location to the ceiling duct location, I ended up a tiny bit off so the duct is a tiny bit crooked and I ended up with a quarter inch gap on one side of joint. I don't know if 1/4" is a decent tolerance for HVAC pros or if they're all shaking their heads sadly as they read this, but in any case it's not going to leak air any time soon because I put a couple layers of foil tape (NOT duct tape!) on the outside and filled the gap on the inside with about a pint of mastic. Do pros use a spatula to apply mastic? Maybe not, but it sure works great!

Luckily, we had a couple of unseasonably hot days this May so we've already had a chance to actually run the swamp cooler. Our outside thermometer said 96°F, and I'm pleased to report the cooler made Lemontree and the kids cold enough to put on sweatshirts. So, I guess that means it works.

So far it seems ridiculously oversized, though. I got a 5,000CFM cooler with a 1/2 horsepower blower motor for a 1,700 sqft home. The recommendation is to replace all the air in the house every 3 minutes. On low, it moves a good amount of air. On high, it's a freakin' wind tunnel. It's almost like rolling your car's windows down on a highway. So, I fully anticipate running the blower on low 99% of the time. Maybe when it hits 110°F I'll be glad to have a highway speed -- er, I mean a high speed -- available, but for now low is good and costs half the electricity as high... and this thing already uses about 1/3 the electricity of "normal" A/C, so the savings are even more than I expected.

I was right about the noise thing, too. Our neighbor's outside central A/C unit is probably 50 feet away behind a wood fence and I often hear it growling when I'm outside. Our cooler, on the other hand, is almost silent. On low, I can't really hear the blower when I'm outside. The hissing of the water valve letting in a trickle of water is actually the loudest thing, and even that sounds like a whisper at ground level. From the inside of the house, you can definitely hear the hum of the blower motor but it's about the same noise level as a central A/C blower, so it's not objectionable.

In short: I'm happy. :)

One step closer to cool

Been super busy installing the swamp cooler, as the weather is getting downright warm at times. I finally got the duct, but haven't installed it yet because the electrical conduit needs to run behind the duct. Installing the duct first would have made the electrical a nightmare (and it's already pretty nasty).

There are two ways to control a swamp cooler; one is line voltage. Line voltage is when you run big full power (120V) wires to a switch on the wall, then run a bunch more big wires to the swamp cooler. That's a lot of expensive wire (copper ain't cheap!) and those switches tend to burn up in a few years when run that way.

I chose the alternate way, which is low voltage. If you have a furnace or central A/C with a thermostat, that's exactly how those are all controlled. Your furnace or A/C has a little transformer in it, that produces a small amount of safe, low (24V) voltage which goes through inexpensive little wires to your thermostat. You'd get a tickle from it, but it shouldn't kill you or start any fires.

Ordinarily, you'd need to purchase a swamp cooler specifically designed for low voltage ($$$), or purchase a $150 conversion kit which is an ugly box mounted to the outside of the cooler. I didn't like those options, so I used something called a RIB from a company called Functional Devices. A RIB is a "Relay In a Box", and a relay lets you use low voltage to control line voltage. Neat, eh? The other nice thing about these RIBs is they're individually replacable, so if one fails I'm just replacing one $20 RIB and not a $150 control board.

So, I tapped into the low voltage source from our gas furnace:

You're not required to do low voltage connections inside a box like you are for line voltage, but I put mine in a box anyway just because I wanted things to be tidy. I'm saving a ton of money by doing this myself vs hiring someone, so a couple more bucks isn't going to break the budget.

The inspector actually didn't like how short I left the above wires, so if you do something like this be sure to leave 6" free length on each conductor. But, the inspector let me slide this time.

Rather than have these RIBs mounted inside the swamp cooler (subject to moisture damage!), I mounted them in the attic on a scrap of 2x6 lumber. Mounting everything to the lumber beforehand let me do most of the work in my cool, clean, well-lit workshop standing comfortably rather than laying facedown in nasty insulation at 100°F:

The blue box off to the right side houses all of the low-voltage connections, so that only line voltage connections exist in the main gray box. (Don't want to mix the two together, for safety reasons.)

The inspector passed my work (and by the way I also got a plumbing permit for the water line and that passed inspection as well) so now I can try to figure out how to install the duct... hopefully before we start getting too many 80°F days!

Finally

At last, I can walk barefoot in my bedroom for the first time since we moved (about 10 months ago, we figure). New carpet wasn't cheap but it sure feels great!

I really have been busy...

Too busy to update the blog. But, here is a little snapshot of what I've been working on. See, our swamp cooler is mounted between 24" roof rafters, but the 20" duct has to come down through the ceiling, which is constructed of joists 16" on center. 20" duct won't fit in 16" space, basic math theory proved by physics. Solution is to cut a hunk out of the offending joist and reinforce the cut area with "headers". The headers are secured with code-approved steel hangers, and the hangers are secured with code-approved fasteners -- ordinary screws are too weak.

I did everything by the book and to code, though this will not be inspected because no permit was required. When it comes to sawing out part of your house, it ain't the place to skimp. Since we have a low-pitch roof, there is no room to stand or even really sit, so I had to do all this on my belly... rolling around in intimate contact with the insulation. No fun. No fun at all. Spent all Saturday afternoon on it. This swamp cooler had better be worth it!

Now that I have a space for the duct, I'm waiting for an HVAC contractor to supply the duct itself so I can install it. Hurry up and wait...

Doggone it

Sometimes you want to hold small items in your metal lathe, for example, to turn a regular screw into a dog-point screw. (A dog-point screw has a little unthreaded nub at the tip, to guide it into the hole you're going to screw it in to.) Unfortunately, gripping tiny items with only the tips of your chuck jaws will damage the chuck. The chuck also can't hold on very well, so your tiny item tends to get ripped out of the chuck -- doing more damage to the chuck (and to itself).

The solution? Make a work holding device. This one started out as 1/2" 12L14 (free-machining steel) round stock, about 1" in length. In the back end, a large hole big enough to pass the entire screw (in this case an Allen head, properly called a Socket-Head Cap-Screw, or SHCS) was drilled most -- but not all -- of the way though, to make sort of a cup with the front end still closed.


Then in the front end, I drilled a much smaller hole  -- and this is the clever bit -- tapped threads to match the threads of the screw. The length of the front hole is calculated to allow 5 full threads of engagement (4 threads would be sufficient, but I like to over-engineer). This produces a hollow tube. The screw is slipped into the back and threaded in so it sticks out the front, thus:

 

In essence, I gave my screw a really big head (hey, it happens to all of us now and again). Now I have a nice, big, 1/2" diameter 1" long item I can safely and securely chuck, and then machine whatever I want to on the end of the screw. (In the picture above, the dog point has already been completed.) Luckily, the lathe's normal direction of rotation tends to seat the screw threads more securely into the holder under tool pressure, so things don't go haywire when you start cutting. (Speaking of haywire, my first attempt at this sort of holder ended in an ugly mess because I made it out of aluminum. So, steel is definitely the material of choice for this job.)

When I'm done machining, I just stick the Allen key in the open back end to unscrew my screw from my holder.

In other news, I bought some 1144 steel (A.K.A. "Stressproof"). Not for any particular purpose -- just to have some on hand for as-yet unimagined future projects... and because I wanted to try it. 1144 is about 3 times stronger than mild steel, yet paradoxically, it machines wonderfully. Plus, it's a little cheaper than 12L14, so 1144 is now my second-favorite steel alloy. Still nothing compared to the sheer joy of machining brass, of course, with it's golden fountains of tiny chips; but sadly, brass is over 4x the cost of steel -- making it uneconomical for many applications. :(

Lights, workbench, action!

I had actually built a workbench in early January, but the shop was too dark and cold to use it. So, today's little project was leveling the workbench, securing it to the wall (it's a little top-heavy and tippy), and hanging lights.

The bench is made from I think 3 2x4s and 1 sheet of OSB, cut in half and layered 2 deep. It's just temporary, though -- just to get things rolling until I get the nerve up to gut and rennovate the whole shop. The walls of the shop are dirty and full of holes, and because of the holes, we can see there are large sections with no insulation. Also, the old inefficient T12 lights all need to be replaced with modern T8 fixtures, and the existing lights are all in the wrong places anyway (and of course there aren't enough of them).

All this adds up to stripping everything down to the studs, insulating, putting up new walls and ceiling, and running new electric. You'll notice I put electric after walls -- I think I want the electric all surface mount, so it can be extended or reconfigured without tearing into walls.

Until then, I also put up temporary lighting for the temporary workbench. Conveniently, an outlet was right where I needed it to plug the lights into the ceiling. About time something happened in my favor...

Yeah, snail's pace is right

I spent most of January and the beginning of February sick, so progress has been frustratingly slow. The house is livable for now, so I've been trying to get my workshop in some semblance of order. In the beginning of January, I ordered a window-mount heat pump. I'm sure you're all familiar with window mount air conditioners, but here in Idaho, we usually need a lot more heat than cool. A heat pump will cool in the summer, but more importantly, it will heat inexpensively in the winter.

Ordinarily, an electric heater is expensive to run. All electric heaters are nearly 100% efficient, but even though they don't waste power, they sure guzzle a lot of it! A heat pump does run on electricity, but uses about 1/3 the juice as a pure "space heater". So while not as a cheap as natural gas, it's still not too shabby.

Few window A/C units work as a heat pump. Most A/C units with "heat" are merely space heaters. Fine, perhaps, for climates like California, Texas, or Florida where heating is seldom needed, but not so much for Idaho. No, a window A/C with heat pump is pretty rare. In fact, I think Amana is the only company that makes them (and, surprisingly, they're actually still made in the US!).

Now, there are plenty of PTACs (like what you find in many hotel rooms) out there by GE and others that are heat pumps, but they're all 4 feet wide so it's unlikely you'd put one in a window. PTACs are good choices for heating/cooling a shop or garage, but do require a big ol' hole in a wall.

As it happened, my shop came with a hole in the wall above the window -- a small hole though, so rather than reframe, I just got a window unit that fit the existing opening. The good news is, it has plenty of capacity to heat and cool the space, being 11.5k BTU/h. A 19k BTU/h Amana is even available in window-size, but would have been overkill for us -- oversizing a heat pump is almost as bad as under sizing it, as it leads to moisture problems (not good in a machine shop filled with steel that can rust!)

As it happens, my heat pump requires a 240V outlet. No problem, Lemontree and I are already honorary plumbers, so I can be an electrician too, and install one! Actually it's not that simple, I did spend a week or so researching the NEC electrical codes. There are lots of rules to follow, but that's okay as those rules are what keep us from getting electrocuted or having our houses burn down.

After careful study, I applied for a permit, purchased about $40 worth of materials (copper wire ain't cheap!), and pretty much finished in two evenings. I was just about ready to have it inspected, when I got sick again and again. Just as soon as I felt halfway human, I'd get hit with something else. So went about 5 weeks. Finally though, today I passed the inspection and with Lemontree's help, hoisted the heat pump into position. And it even works!

Now that the shop can be a warm and pleasant place to work, hopefully I can get more things done. As long as I don't catch yet another bug...

At a Snail's Pace

I just wanted to post a quick update to our various projects. Maybe Corwin will find some pictures and post them later, but in the meantime, I'll just tell you what we've been up to.

First off, it was great to get the chicken coop to a stage of completion that we could put the chickens in there for a whole day with extra food and water so we could visit family for Christmas without having to bother neighbors to care for our hens. We just screwed the egg doors on for the time being and hung the man door. Finishing the coop and building a fence is now going to have to wait for warmer weather AKA ground thaw. We still need to attach the egg doors properly and side and paint the whole thing. We'll need to put up a fence, and I'm considering options to keep the hens from flying over and perhaps keep some predators out. A few days ago, a red tail hawk bumped into the house on it's way down, quail hunting. I'm glad it wasn't a chicken tha got caught!

Corwin has started putting his shop together. He's had to add a new receptical for a heat pump he ordered. I'm sure he will soon have a post about his exciting adventures as they develop.

Inside, we have been working on our "bonus room". We had to tear out part of the subfloor and drywall, as there had been moisture damage. We patched the doggy door hole the previous owners had put in the wall, a doorway that led to the master bedroom, and various other holes in the wall and ceiling, including the hole for the water heater vent that we removed. We tore out wiring as well, deleting two wall switches and a ceiling outlet. After all that, My brother and my dad came over to help me tape and mud the bonus room and the master bedroom for good measure (remember the doorway we walled up?). My brother then textured both rooms for me. I'm so appreciative of his help. He came back three days in a row, using his time off to help me. My dad brought me his paint spraying machine, and after a few hiccups getting it to work right for me (it needed a new filter installed), I primed both rooms, and painted the bonus room a nice pastel yellow. I'm waiting on Corwin to decide on a paint color before painting our room, but he still has workshop on the mind, so I'm waiting (im)patiently. We still need to put in the new subfloor (there was a moisture barrier that protected the bottom layer of floorboards, so we were able to work around it), paint and replace the baseboards, then have new carpet installed.

Nothing comes together as quickly as I imagine, but we are moving along slow and steady. What with keeping up with a household, and flu and cold season taking it's toll, the fact we can get up and get back to work is a great blessing.

Budget ridge

The roof is done! After I did about 2/3rds of the shingling, Lemontree tried her hand and then ended up finishing. I was much happier fetching shingles and flinging them onto the roof for her than I was nailing them down myself.

Here I am, putting the ridge on. As you can see, we used "architectural" shingles, to match our house. However, the ridge shingles for architectural roofs come in a box for like $60 and one box contains enough ridge shingles for three chicken coops. Too rich for our blood! Instead, we just got a pack of cheap 3-tabs from the same manufacturer* as our architectural shingles, and in the same color. Then we cut the 3-tabs into thirds, making them 1-tabs, and used those to lay down the ridge. (I dunno if that's kosher for a human dwelling, but the chickens don't seem to mind.)

Both top rows of architectural shingles bend over the peak, and so do both top rows of tar paper underlayment, so even with a "cheap" 3-tab ridge it's gonna be real hard for water to find it's way in through 6 layers.

Even though we only bought 1 pack, we still have a ton of leftover 3-tabs, so there's plenty to re-ridge after 20 years when this ridge fails.

We also got the rest of the sheathing on. Lemontree will cut in a window on this side later.

* The shingle manufacturer, if you're curious, is Owens Corning. We got that kind because that's the kind Lowes carries, and Lowes is the closest place to our house. (We selected Certainteed shingles for our real house, because they seem to be the best and that's what the roofer with the cool German accent uses.) If the Owens Corning turns out to be trash, oh well, it's just a chicken coop. And since the coop was roofed by amateurs anyway, any failures are more likely to be due to the installers rather than the product used.

Structural rigidity

We took a little break from roofing, because it was becoming obvious the whole thing was a little wobbly. The sheathing -- OSB in this case, but you could use plywood, particle board, whatever -- is what keeps those stud walls from racking or becoming a rhombus. Stud walls are good for holding the roof up, but can't resist sideways forces... such as the ones I set up when I crawl around on the roof. Good thing I don't get seasick.

The coop is now solid as a rock, as any building should be. Above, you can see a cutout for the egg door. Below, you can see the opening for the people door and inside past it, the two tiers of nesting boxes.

 

Without a ceiling, nasty chicken-eating animals like racoons could climb right up through the attic and down into a smorgasbord of fine dining options. It was all hands on deck to get that installed, the kids helped hold it in place while I zipped screws through it into the truss chords. Good thing we ponied up the extra $2 for 1/4" plywood vs the 3/8" OSB -- the plywood is feather-light in comparison.

We have shingles

No, not that kind of shingles! This kind:

You can also see the cedar fascia. And if you think the fascia looks suspiciously like 3/4" thick fence pickets that have been ripped down to 5" and the dog ears cut off... you'd be right.

Corwin, the roofer

Got the chicken house decked, tar papered, and edge-metal'd today. That sounds simple to say, but it took us all day to do that.

First, we used nails to space the sheets of OSB. Should they expand with moisture or temperature (for example, they were installed at 34°F but will see 120°F in in the summer sun), we don't want them to lift or buckle at the edges like the Rocky Mountain range. The OSB was attached with screws around the perimeter (to resist wind uplift) and nails in the field (cheaper, faster, and more fun to drive with a palm nailer. B-b-b-b-blat!)

Next we cut lengths of 15lb tar paper (sometimes called felt paper, for reasons unknown to me) on the ground and tried to get them on the roof without tears (either kind). A random website said to use the fewest fasteners possible, so I just used roofing nails on the corners of each sheet. This critical error revealed itself to us right after we finished the last sheet, when a gust of wind ripped it right back off, leaving little holes in the paper the exact size of the roofing nail heads. Apparently, using the fancy nails with 1" plastic caps isn't just something roofers do for fun. Stupid website. So, off to the store for cap nails, back to replace the torn tar paper, then go crazy sinking plenty of cap nails everywhere. Ugh.

Then it was time for fascia. Actually, we should have done the fascia before trimming the tar paper flush with the decking, because ideally the tar paper should protect the top of the fascia too. Too bad, we're newbies and messed it up. Fortunately, the edge metal will still cover the fascia top so no biggie. No picture of the fascia, we had to rush to beat the clock. Lemontree did a good job figuring out the compound angles to cut all the miters (where the gable fascia meets the eave fascia for example is complicated). Thinking about doing all those angles the right way makes my head hurt.

By this time the sky was getting dark and little snowflakes started to drift by lazily. I wished I could also drift by lazily, but we needed to get the edge metal up before the wind blew more of the tar paper off, cap nails or no cap nails. So we tried to shake feeling back into our frozen fingers and got out the tinsnips. In our house, tinsnips are normally never actually used to cut tin, but instead are used to open items in those stupid bubble packs. Today, though, we cut T-shape drip edge metal for the eaves and L-shape drip edge metal for the rakes (rakes are the edge of the roof over a gable wall). The T-shape eave metal goes under the tar paper, so that any water that gets under the shingles, goes over the tar paper and eave metal to keep it off the fascia. The L-shape rake metal goes over the tar paper, so that wind-driven rain cannot get between the tar paper and the top of the fascia.


So, our roof didn't turn out quite as pretty as Tom Silva does it on This Old House. Despite lots of care measuring and cutting our trusses, the rafter tails somehow still ended up at various heights so the decking looked a little drunk when you looked down the length. We also kinda sorta made the whole coop a bit of a trapezoid rather than a square (my fault) so the north wall is some 7" longer than the south wall... this required the installation of oversize decking, which was then trimmed with a circular saw. Ok so I can't cut straight with a circ saw, they didn't teach that skill in school. So now we have wavy decking edges up and down and side to side. Sigh. They say, though, that the difference between the master and the apprentice, is the master knows how to hide his mistakes. Well, I would never claim to be a master but we pushed and pried things a little straighter when we screwed the fascia on, then covered the remaining uglies with the edge metal. Once the shingles are on, I don't think you'll be able to see any flaws (fingers crossed).

At the end it was totally dark, sorry for no pic. But the roof is "dried in" with tar paper protecting the OSB so the OSB doesn't melt should it rain. Sadly though, we only get maybe 1 hour of light after I get home from work each day, so shingling is likely to take all next week.

I must say I have a newfound respect for homebuilders, and now I understand why houses are so expensive. Doesn't make me feel any better about making mortgage payments though.

Chicken house

Chicken house is starting to look like a house. I don't think we can really call it a coop, since it's big enough for me to walk around in. At least, if I don't mind whacking my head on the truss chords. Every. Single. Time. Ow.

Here I am trimming the rafter tails with a circ saw in between rain showers. I bought the lumber for the rafters a little long, as we had not yet decided on an overhang size. Lemontree settled on 2', or thereabouts.

Note: Do not attempt to build a house based on what you see here. We've used 2x4s 24" on center, with wooden gusset plates to make longer lengths out of our reclaimed lumber. Of course that is not strong enough for human habitation, but I'm pretty sure it won't blow down in a strong wind, or collapse under a winter snow load. On the other hand, if there's an earthquake, I hope it happens while the chickens are outside.

Here's a little bit of fun. The ladder to the nesting boxes takes up a lot of room, which makes it hard for humans to get in periodically to muck out the... er, muck. So,

it hinges up. (The hinges are also reclaimed from the former hot tub.) Additionally, there is a carefully engineered, cantilevered 2x4 cut at an angle under the landing. It provides solid support for the dead load of the ladder as well as the live load of 7.3 average chickens... just don't let the kids sit on it.