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June 18:

 I got a start on the tank today.  I set out the first coarse of blocks with spacers (middle image) and was able to drill holes into the slab for the rebar to tie into the floor (left image).  I was also able to drill holes into the walls and insert short pieces of threaded rod to tie the blocks into the wall (right image).

June 30:

Still working on the tank. . . Two out of the six rows are mudded in.  This kind of work always takes longer than you think it will!




July 4:

Still working on the tank. . . Up to row three now.  My back is starting to hurt!

July 9:

Finished filling and pointing up the third row and began laying blocks for the fourth row.  The overall tank size is turning out slightly larger than originally planned.  I am thinking of going one less row high due to the cost of all the mortar and concrete fill.  I think the tank will still come in around 1000 gallons even without the last row.  I am also worried that with six rows the height will not leave enough room to easily get the insulation, liner, and piping in the tank.

July 25:

I have been busy over the last few weeks finishing all of the concrete work on the tank.  It is now complete and ready for the wood to be attached to the top.  Next I will put the polyiso insulation in and the liner.  I have purchased all of those materials and have them on hand.  I have also cut into my existing system in three places and put ball valves in to allow re-pressurization.  I have been laying out and mounting some of the new components which will be connected using 3/4" pex. 

July 29:

I have now anchored all of the wood to the top of the tank and to the concrete walls.  I lined the tank with thick plastic to act as a vapor barrier.  I also started to cut and put in the insulation.  I am working on soldering the fittings to attach the tank pumps and the flat plate HX as well. 

August 1:

I had a very productive day today.  I got the rest of the insulation in the tank and was able to cut and put in the liner.  Most of the liner is anchored down now, but I still have a little work to do on the corners.  I have started to construct the fixed piece of lid that the pipes will pass through and hope to get to plumbing the rest of the system soon.

August 8:

I've been working on the DHW preheat coil for the last few days.  It consists of a 10 foot 1/2" copper loop in the bottom of the tank that then feeds into a 60 foot 1/2" O.D. coil and then into another 10 foot 1/2" copper loop near the top of the tank.  The top and bottom loops are supported on a CPVC frame secured with copper wire.  The copper coil had difficulty retaining it's shape so I wove and wrapped copper wire down opposing sides to stiffen it.  


The DHW enters and exits from the tank through the top of the tank with CPVC and converts into copper.  At that point there is a copper union which will allow me to remove the loop and coil structure if necessary in the future.  


I have decided to run all of the tank side piping for charging and drawing with CPVC.  It will cost considerably less than copper would and CPVC can go up to 180° so there should be no temperature limit concerns.




August 15:

 Here are the preliminary runs of pipe through the lid.  I cut a smaller hole than the pipe diameter using an X-acto knife and pushed the pipes through.  Then I clamped it down with a stainless steel clamp.

Here is the DPDT relay all wired in with armoured cable.  I mounted the socket to the cover plate.

Here are the tank pumps and flat plate HX piped up.  The tank side piping is in CPVC.  Note the fill/drain valve and the ball valve on the top CPVC line.  I prime the lines by closing the ball valve and running a garden hose to the fill valve, then opening the ball valve and kicking the charging pump in.  Worked well.

Here is the top of the lid where the pipes come through.

August 24:

I have now finished all aspects of the tank and piping.  I am currently charging the tank.  The flat plate works very well and there is about a 10* temp differential between the top and bottom.  I am very impressed with the flow rate pumping through another pump and the DPDT relay controls the pumps not running at the same time works perfectly.  I will put up some more picture soon.

 August 29

 It took two days of burning to bring the tank up to temperature.  I had not considered how long it would take, but this seems reasonable since it had to come up from cold tap water.  I charged it to 150* and stopped because I am only using it for DHW at the moment.  I may try to bring it higher just as a test on my next charge.

Stratification was good initially during charging, but by the end of the two days I was getting strange readings that the bottom of the tank was hotter than the top.  I discovered later that when no pumps are running that thermo-siphoning was starting a flow through the pipes from the top of the tank to the bottom.  I diagnosed this because the pipes were always hot to the touch, which seemed odd when no pumps were running.  I closed the the ball valve and the pipes became cold to the touch.  I am working on ideas for how to stop the siphoning flow when the pumps are off.  Stratification returned once the siphoning was stopped.  There is at least a 5* difference between top and bottom now.  I hope that without the siphoning on the next charge I can get higher stratification.  If not, there is probably something else causing mixing as well that will need to be addressed.

 On a better note, I am enjoying DHW from my coil in the tank now.  I think the coil is sufficient on it's own and I will eliminate the need for the coil in the oil boiler to be used at least during the summer.  I think I will have less heat loss if the tank does not have to keep the oil boiler hot as well as preheating the water.  I have close to 90' of coil for DHW in the tank and the water gets plenty hot.