And Let the Piping Begin

   Well it had to happen sooner or later, I put to big holes in the side of the house.  But it wasn't as easy as I thought it would be.

   I purchased a type of holesaw called a SwitchBlade.  It is a neat design with replaceable blades.  There were two problems.  First, given the 2 9/16" hole that I was trying to drill, the shank required a 1/2" drill, which I have.  Unfortunately, the switchblade does not just cut the outer edge of the hole, like a traditional holesaw, it removes the inner material as well.  Which brings us to the second problem, the drill didn't have enough torque to drive the bit.  So the bit kept getting stuck.  As can been seen in the pictures, I tried making Swiss cheese our of the middle of the hole with a smaller bit, but this didn't help.  So, a $50 drill bit was set aside and back to home depot I went.

    Starting with a 2 1/2" hole saw that I owned. I managed to drill out the rest of the hole without stalling our the drill.  The important thing here is that a traditional holesaw does not grab.  So you can cut slowly.  Also, energy is only being expended at the outer edges of the hole and the middle is left alone.  This makes drilling more rapid.
   With the 2 1/2" hole drilled, I was a little worried.  I actually needed 2 3/4" hole, but now wasn't sure I could even use a bigger holesaw.  Holesaws work from a center pilot drill bit, but the center of the hole was missing, so no piloting.  But I purchased both a 2 5/8" and 2 3/4" bit and found that I could get them to enter the existing hole and have them self pilot based on the hole edge.  Success and another $50 spent for a total of $100 to make two little holes.
   What made this a little difficult was that I had to drill through the sill which on my house appears to be one solid 4×8.  They don't make them like that anymore.

    Supporting the pipes will be a little bit of a challenge.  Looking on line, I found no less than 12 different types of pipe hangers.  None of them seemed appropriate for supporting an insulated pipe.  Most pipe hangers support the pipe over a very narrow width.  If I did that with the insulated pipes, then the insulation would get crushed.
   So I decided to design some of my own supports out of bent aluminum sheet metal.  The image below shows one bracket that I used on the return pipe.  It cradles the pipe right up next to one piece of Misumi aluminum extrusion.  The support is 8" long and can spread the pipe weight over a long enough area to avoid insulation crushing.

   Then an alternative design was made for the supply pipe.  This is effectively a U-shape which I hung off of a short piece of 40×40 aluminum extrusion.

    The same design was used in a second location to support the supply pipe

    Frustratingly, I still don't have the long radius elbows that I ordered from PexSupply.  First they sent me the wrong parts, then the next order was held up due to some back ordered parts, and when I finally pushed them to ship the 90% of the order that was in stock (including the elbows), they had sold my elbows to someone else and the elbows were out of stock.
      But as it turns out, there was at least one pipe that I could get started on that didn't use the missing elbow: the supply pipe from the solar panels.  The supply pipe from the solar panels serves a could of different functions.  As it happens, this is always the highest point of the system, so it is important to put an air bleed valve there.  However, apparently these valves have a nasty habit of failing.  So just before the air bleed valve, it is recommended that you place a 1/4 turn shut off valve as can been seen in the picture.  Both the air bleed valve and the 1/4 turn valve came from Caleffi and are specially made for solar applications.  Although these items can be purchase from a place like Home Depot, they will not be rated for 275F or outdoor use.  These items were attached to a special elbow sold from Heliodyne.
   Also at this location, the temperature of the solar fluid must be measured.  So Heliodyne makes a special will "well" piece into which a thermistor can be placed..  I have not installed the thermistor yet, but when I do, I hope to run the wires inside the pipe insulation which should make for a very clean install.

 

  The first section of pipe was soldered together and is supported by one of the custom brackets.

 

   Also, the solar hot water thank is on order.  I chose an 80 gallon stainless steel models from Heat-Flo (HF-80).  It is expensive at $1800 (with shipping) but hopefully it will last forever.  I was really torn because A.O. Smith model SUNX-80 looks excellent.  It has less than half the flow resistance of the Heat-Flo.  If I recall correctly, the A.O. Smith model was equivalent to 18 feet of 1" pipe, the Heat-Flo was 60 feet, and the SuperStor was 250 feet.  I was amazed by how much difference in flow resistance exists between the different hot water tanks.   Hopefully I can get the 2.5 gpm flow rate that I need despite the high resistance of the Heat-Flo tank and the Taco Sentry Zone valves.