Monday, August 31, 2009

August Performance for the $1K Solar Water Heating System

The performance for $1K Solar Water Heating System is in.   This is the day by day performance plot

The solar fraction for the month was 100%.

I'm going to continue the logging through September so that there is a full year of monthly performance plots.

Here is a road map of all the pages on the design, construction, testing, and performance for the system.


  1. Gary, even though the pump only draws a slight amount, might it be worth it to consider putting in a relay so the draw on the controller is less? Seeing that you are having that problem, I will certainly put mine on a relay. I already have one to use, and a new pump to install. I just need to get it plumbed. All of the smaller pumps I have tried have been too low head for my application. The pump I have to use now is a centrifical that will pump at least 100' of head, so I shouldn't have any problem with the application.
    Also, one thing I have found, is that my pex tubing has developed slight air leaks. I think this is due to the high stagnation temperatures, on days when I didn't run the system. I have to manually start my system, till the new pump is installed.

  2. Hi Doug,
    The controllers are supposed to have a relay or equivalent output circuit to switch a pump. My Goldline controller has been working fine on the 85 watt pump that it switches, so it seems like a 13 watt pump should not be a problem?
    I plan to drop Steca an email to see if they have an explanation.
    I'd like to hear how the overheating thing comes out. If it did result in a failure of the PEX, it would be nice to know what the failure looks like and where it occurred if you can easily find this.


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