Great idea, but yes at $500... wowser, I wonder how it works? If it is always on or just when a certain temp kicks in?
On another note, I have found that on my solar controller ( the basic SunEarth-Steca model) there is a hidden menu that allows me to set the pump to come on if a high loop temp is reached. By default it is 261 degrees. It can be adjusted.
Does anyone feel that 261 is too high?
Thanks as always!!!!
Hi,
Some of the controllers have a couple features designed to address overheating the antifreeze -- my Caleffi controller has these two:
- You can set the maximum tank temp to (say) 160F. This will shut the pump off when the tank gets to 160F.
- Now if the collector temp goes above a value that you set (say) 250F, then the pump will come back on even though it will heat the tank above the 160F. This allows you to protect the antifreeze in the collector from excessive temps, but it does boost your tank temp higher than you wanted to (probably a good tradeoff).
The pump goes back off when the collector temp drops a few degrees below the 250f (or whatever you set it to).
- Then at night, there is a feature that can be enabled that turns the pump on if the tank temp is over the 160F (or whatever you set). The idea is that if you used the feature just above to protect the collector during the day, and you heated the tank hotter than then 160F limit, then this feature allows you to pump fluid through the collector at night to cool the tank back down to the 160F (or whatever you set).
My guess is that the Steca has these features.
http://www.solarhotusa.com/support/literature/files/StecaTR0301UHiddenMenu.pdfIf the tank gets up to the high limit you set frequently, then you maybe your tank volume is a bit small for your collector size?
If you can do it, increasing the collector tilt angle will decrease summer overheating and improve winter performance as well.
Some people use a dump load to (eg hot tub or loop of pipe in the ground) to dump excess heat.
Gary