Upgrading an AC immersion heater to 48V DC

DThames

Photon Sorcerer
Most thermostats made for AC will not be reliable with DC, as the points can arc with each opening, causing all sorts of problems, including welding the points together. Generally you can swap out elements if the threads fit. I have considered this but I would get a simple temperature control that could switch a DC relay or build a relay driver circuit for the standard thermostat.
 

Groscout

Solar Enthusiast
You're on the right track. Just don't forget that the "T&P relief valve" has to be correctly rated for the heating element and that it is properly discharged to the exterior. The discharge line can ONLY run down hill from the T&P, reason being is that a trap/water setting in the line could freeze and create a plug in the line thus a potential bomb. Eg:
 
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