Sun Start Refined Apparatus

I rebuilt the Sun Start Chimney pipe with a little more patience and time spent scrounging my garage for better fittings. I was able to find a bronze adapter, but a less expensive piece would have been a 1/2″ SWT to 1/4″ FPT copper fitting. I sweated this together and wrapped it with a few feet of high temp pipe insulation. I also inserted a loose plug of copper scouring sponge down the pipe to reduce fluid loss. I’m looking forward to another sunny day to try it again with the insulated version.

(October 1, 2013) I’ve since told Eldon Haines about this and he built his own out of three-quarter inch copper pipe. I think this is probably advantageous, but we didn’t have enough sun to test it and I haven’t heard from him whether or not it worked. My guess is that it will work better than the half inch pipe because less fluid will be ejected from the end of the pipe. I also found that it does take quite a while for the system to heat up to above atmospheric pressure after you stop the flow through the heat exchanger on the domestic side. The system still has to heat the water that is in the domestic side of the heat exchanger, about a gallon, and that takes some BTUs.

Chimney-pipe parts



SunStart Chimney Pipe Refined and insulated

2 thoughts on “Sun Start Refined Apparatus

  1. Good job finding cheaper fittings, and especially using sweats rather than Ag-brazing. How do you get temperatures high enough (BP 15% MeOH ~200°F) when the systems are working, but with ∆T~50? I’ll try this on the Rose House…

  2. To burp a system that’s already running at or below atmospheric pressure I have two solutions:
    1) stop the flow through the primary side of the heat exchanger with either of the 3-way valves (capped). Without losing heat to the HX, the system will pressurize in minutes.
    2) open the system to air pressure then re-seal it for a few minutes of full sunlight. It will pressurize and you can allow the excess pressure to release the air with the steam.

    I didn’t time my procedure, but I know I let the steam flow for only a few minutes. I think letting it flow for several 1 minute intervals should be sufficient for burping. But for a new charge, I think you’d have let the system run open for a while, cover it, add liquid after it’s cooled down to atmospheric pressure, let it run again for awhile, until the ∆T is stable below 50, check the fluid again, add ‘the right amount’ per the installation manual, and then burp it with few intervals of overheating with the HX blocked.

    What do you think?

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