Last Sunday my friend Mauricio and I extended the plumbing for the loop that will cycle distilled water through the panels.  We also mounted a piece of 3/4" ply to the framing I built to mount the Steca TR0301U controller.  I realized today that perhaps I should have used some kind of dialectric union between the iron pump flange and the copper pipe to avoid galvanic corrosion.  Luckily this is easy to add at this point as I haven't sweated anything into the pipe beneath the pump.

 That got me online researching what kinds of dialectric unions to purchase.  I read many opinions on DIY and plumbing forums that suggested that water temperatures over 160 F can quickly degrade your typical galvanized steel-to-rubber-to-brass union.  The hot water loop through the panels should be able to easily achieve those temperatures, so I'm left wondering what to do.  So many questions!  I have a email in with Solartrope to get resolution on this.

Next to do is hooking up the galvanized steel pipe to the cold and hot water ports on the SunEarth tank.  Again, dielectric unions will be required to transition to copper and I have the same issue of running very hot water through the unions.  My understanding is that the water in the solar storage tank will very often be scalding and that it's the mixing valve that ultimately modulates the water temperature.  

The panels are still lying on the roof awaiting my purchasing Geocel roof sealant and the right kind of membrane roofing.  It's slowly coming together...

Drainback Tank Mounted

I have mounted the drainback tank although in these pics I had yet to tighten the #6 bolts that hold the 3/4" pipe straps to the aluminum angle brackets that I fashioned. I put a couple lengths of bicycle inner tube between the aluminum angle and the copper 3/4" pipe to prevent galvanic corrosion. Tightened down, the framing, hardware and tank feel pretty solid!

This project is a lot of guesswork. The outlets of the drainback tank hopefully will be situated well for hooking up to the solar storage tank. Running copper from the collector return line to the drainback tank will hopefully avoid the spaghetti of ductwork while maintaining the required slope to achieve effective drainback. Sigh... I do not remember any of the PV systems that I've helped install over the years being this complex.

Next I'll be sweating a ball valve to the collector return line, near the ceiling joists of the garage then connecting the drainback tank inlet to that.

Situating the Drainback Tank

I scrounged two hours today between car wash-like winter storms and a mexican themed dinner that I was co-cooking for to build a stand for the five gallon SunEarth drainback tank.

The stand will have to cope with 70-ish lbs. of water and copper, so I anchored it to the existing hot water heater stand, the wall studs and ceiling joists. It's not going anywhere. The tank itself is a bit strange to mount. It can be seen in the picture as the matte black painted object in the lower right quadrant. The insulated parts do not afford a good attachment point as it would compromise the insulation. The top and bottom tubes I believe offer the best place to clamp it in place, but it will require some burly angle aluminum that I had left over from a Burning Man project and 3/4" plumbing brackets to make it work. I'm not sure how other folks do this. Part of the `fun' of this project is guessing what's required. Is this all to code? I hope so...

From Garage to Attic

Below is a picture of our upstairs bedroom closet, the back wall of which is situated just above our existing hot water heater. Behind that back wall is a space about 12" deep, 30" wide extending from the second floor up into the attic.

I knew from peeking at the space from below that it was a straight, sheltered run from where I had intended putting the solar storage tank to where plumbing and sensor lines would have to dogleg into the attic before the final run to the collectors. Below is my first bashful cut into the wall.

I'd shortly come to realize that the whole wall would have to come down. The 10" galvanized pipe on the left concealed an 8" diameter ceramic chimney that used to vent a wood stove that long ago was removed from the kitchen. It was all perched upon 4" thick disk of cement that was resting on the floorboards. At this point I was just hoping that I'd be able to get all the heavy sections (2' and ~40 lbs. each) of chimney out alone. I knew they were mortared together with brittle mortar, so I started by nibbling through the steel outer tube in a can opening fashion.

The other flue in the wall was for the furnace and water heater. The joy of working on older homes is that you find nasty old anachronisms at every turn - deep strata of lead paint and wonderful products like `Metalbestos'. Metalbestos exists to this day, although I suspect that they changed the insulation. You can have your Mentos! I have my Metalbestos!

Back to the less deadly tubing... I got the steel tube opened and made relatively short work of removing the pipes. For the more stubborn joints, I used a Bosch rotary hammer with a chisel bit which made doing this *way* easier.

To the left is the offending chimney in it's full glory.

Below left is the chimney removed, the space Great Stuff'ed (TM), R13 insulated with the conduit, bell wire (brown, hard to see), and plumbing installed. I used bell hangers for the plumbing to provide space for the foam rubber insulation with which I ultimately insulated the pipe. The conduit I put in because down the road I might want to install photovoltaics on the roof. The bell wire is for the temp sensor at the outlet of the collectors.

The rest of this job was significantly less fun. I drywalled, which I'm terrible at, and then didn't have quite enough time to fully reassemble the trim and floor-to-ceiling shelving. It created some `tension' the following week when the house was back up to full occupancy, but ultimately I got it all finished and we ended up with a closet that was better organized. Whew!

I'm waiting for FastJacks (3"), Oatey flashings, Geocel and peel and stick roofing for mounting the panels, so I've since turned my attention to mounting the five gallon drainback tank in the garage; more hopefully soon!

Storage Tank Stand and Pad

Found an hour in my day to:
1. Angle grind flush to the garage floor three half inch concrete anchors that had held my bench grinder stand.
2. Cut treated (`ACQ') 2"x4" lumber as feet for a DIY plywood water heater stand.
3. Cut a 2" thick (R10) Dow blue styrofoam pad on which to set the tank.
I've also found a nice plumber (Colin) from Pagco Construction to help out with code questions and potential crisis moments when I need a pro. He told me that there is no water heater stand requirement for electric hot water heaters in SF. Thank you Colin!

Slow Going

I didn't get much done this weekend. What I did do was buy the following and do a bit of basic carpentry:

4'x8' sheet of 0.703" ply
R13 fiberglass insulation
Dow Blue styrofoam insulation panel
4"x4"x8' pressure treat lumber

With the above I hope to create a ~62"x48" wall behind where the solar storage tank will be. Currently the wall is completely unfinished - just studs, mineral felt, and stucco. On the wall my plan is to nicely, neatly mount plumbing pipe, valves, etc. around the tank. As long as I'm finishing the wall, it might as well be sealed (with Great Stuff (tm)) and insulated. The exact timing of which will depend on when I determine how the solar collector loop pipes are going to be run, as I don't want to seal up the wall before I've plumbed it. I haven't figured out how I'm going to get them from the roof to the garage (attic or outside run). I'm hoping I'll get up in the attic and be able to see a clean hole to the garage. As our attic is cramped, filthy, and bristling with cranium puncturing nails I'll procrastic at least another day on this.

I've decided that I should have a plumber on retainer b/c it's annoying trying to figure out plumbing code. For instance, the solar storage tank has a backup electric heater which I'm not going to use, and it's my understanding that electric hot water heaters don't need to be on stands in the garage, but who knows? I might get an inspector who doesn't like the distance between my eyes and thus deem my homemade stand (4"x4" and ply) DIY devilry. Pay now or potentially pay later.

Pardon the whining, but tinding time for all this with a toddler and a busy schedule is probably the most difficult part of this project.

Panels on the Roof

The panels and the 80 gallon (300 L) hot water heater came this past Friday.
With the help of my two good friends Mark and Tom, we wrestled the two 4'x 8' (1.2 x 2.4m), ~120 lb. (55 kg) panels on the roof. We threaded them through my small house, which was a bear. Unfortunately my 16' extension ladder wasn't quite long enough to make getting them up from the ground possible. Happily we didn't drop the panels, bang up the house or throw out our backs in the process. This is definitely a three+ person job!

The picture is looking north over the roof, where you can see downtown SF in the background. For now I'm leaving the panels flat on their backs until I figure out the exact placement of the rack and how best to fasten the rack feet to the roof joists.

Tom's looking up from where we lifted the panels from our small second story deck to the roof. Two lifted from below and I pulled the panels up. A second person pulling from the roof would have made this process slightly less tense. May all our backs feel fine in the morning...