We have a Heatilator GNDC30 direct-vent fireplace unit in our house.  It's wired for a blower unit, but the builder didn't install it (which is pretty common).  Instead of paying someone to come out and stick one in, I decided to order the blower itself and give it a shot.

The blower I got was a non-OEM replacement for the manufacturer's FK21 fan kit.  I'm sure that the OEM kit has a bracket that holds the fan in place under the fire box, but this one did not.  It really only needs to sit under the firebox and shoot air up the back

Th e blower itself is just a small squirrel cage with an AC motor and a variable motor control.  The motor is a little too heavy, so it leans to one side if you don't hold it in place.  During test-fitting I noticed that not only does it lean to one side, but that the opening of the fan is larger than the slot that carries air up the back of the firebox.  I made a little box out of sheet aluminum and stuffed a roll of non-slip in the middle to give me a cutom-sized vibration-reducing block to hold the motor level.  The difference in duct sizing causes a lot of wind noise even at low speeds.  To remedy this, I made a little duct flap out of sheet aluminum to point the air appropriately.  Here are the pieces.  And the final result with the flap installed in the blower housing.

To further reduce noise and vibration, I cut another piece of non-slip to set the whole thing on once it's in-place.  I would tend to bet that the stock unit just mounts to the sheet metal and thus could potentially rattle.

Next, I just slid the whole thing into place in the back of the firebox, and put the little support box under the motor.

It's a little hackish (okay, maybe a lot hackish), but it is a retrofit.  Hopefully tonight we can test it out and see if it makes a difference in heating the living room :)

Taylor and I both seem to be completely incapable of remembering to close the garage door in all but the most simple arrival scenarios.  Okay, maybe it's me more often that not, but still, it's a problem.  Several times, we have gone to leave in the morning and found that the garage door is already open.  Being in such a dense neighborhood, this is also a point of embarrassment, not just security.

So, as I do whenever I need a part of my home automated, I went to SmartHome in search of a handy device
to help solve my problem.  I found some devices that attempt to close the door if you leave it open, but it seemed like user reviews were less than favorable.  I finally settled on this one from Chamberlain that just monitors the door and offers a solid green light when it's closed and a blinking red light when it's open.  I would prefer to have a buzzer attached to a timer to offer an auditory cue when the door needs checking, but it's a start.

Of course, I have considered hacking the device and putting a timer/buzzer in place.  Taylor doesn't like the idea of a hand-made project box being anywhere visible, although I think I might just give it a shot and see how "bad" it is.  I've also thought of making my own, using these neato serial RF transmitters and receivers I found, in combination with encoder/decoder chips.  However, I don't see any reasonable way to have multiple devices on different frequencies, which means I wouldn't want to waste 8 digital I/O channels on just the garage door.  Now I feel compelled to find something else to automate!

Well, after being so happy with my proof that the server room A/C unit wasn't cycling too often, I realized that my sampling rate was low enough (10 minutes) that if it was cycling really often, I wouldn't necessarily be able to measure it.  After some old-fashioned empirical analysis (i.e. watching the unit for about 30 minutes), I decided that something needed to be done.

The real problem is that the A/C unit is being too aggressive at keeping the set temperature.  A single degree of difference will cause it to kick in.  With such a small space and such an oversized unit, it doesn't take long to cool the room, or for it to heat itself back up a degree.  Thus, I needed a way to introduce a multi-degree differential, but without modifying the electronics in the unit.  The condenser talks some serial protocol to the compressor unit, so trying to be smart and switching the signal line isn't an option.  It causes a communication error and forces the whole thing to be restarted.  Thus, I resorted to a physical solution.

 The temperature sensor in the condenser unit was mounted inside next to the coil, which has the main fan constantly circulating air over it.  This makes it very sensitive to the room temperature.  To solve this, I pulled the sensor (which has a nice long cable, thank you $manufacturer) out of the unit.  I put it inside a small length of thick poly tubing, and stuffed some fiberglass insulation in either end of it.  The result is a nice long cycle period and a very distinctive sawtooth shape to my temperature plot.

I have an over-sized A/C unit for my server room, which is both good and bad.  It's good because I have plenty of capacity and can keep the room at 64 degrees in 100+ degree weather (if I so desire) with my current heat load.  This means I could add more equipment and not worry about being able to cool it.  It's bad because it means that the A/C unit might be short-cycling.

Short-cycling means that the compressor might be starting and stopping too often, which reduces the life of the most expensive component.  During the winter, I seem to notice the unit cycling on and off a lot, so I was worried.  Since I have temperature monitoring and logging of the room, I decided to extract and plot some data to see if I could see definite temperature swings this way, and thus figure out how often it's cycling.

I plotted a 12-hour subset of data from a relatively normal 40-degree day, and found that the swings were very obvious.  I counted about twenty cycles in the 12-hour period, indicating about two cycles per hour, which is definitely within the normal range.