Water Heater

[Randyonr3]

I built a system awhile back for Hot water concisting of a solar colector water heater that sits between the solar electric atop the bimini.. Durring the hottest part of the day I cycle the water throu the colector and fill the waterheater with hot water, works great EXECPT,
I personally have to turn the pump on and turn it off..
Id like to install a tempeture differential system that would turn the circulation pump on and off based on the difference of the tempeture on the heater and the colector..
Anyone have any Ideas on the workings of a defferential system that would work for the system..
I've checked into the home units but they all run on 110 and I would like to set it up for 12 volt...

[senormechanico]

I made one on our previous boat and ran into the same problem.
As an electronics tech, I simply looked inside one of the 110 volt units.
Guess what? The power supply for the differential controller takes 110 vac and reduces it to TWELVE VOLTS ! The key was the voltage rating of the main power supply electrolytic capacitor (1000uf @ 16 V.) I didn't even need to measure the output voltage, as I knew it couldn't be more than 16 volts. I bought it and simply dumped the power supply transformer, the full wave bridge rectifier and hooked my battery supply (fused of course) to the electrolytic capacitor right after the bridge rectifier. Worked like a charm.

http://www.cruisersforum.com/forums/...olar-70-2.html
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