Q. I have a hot water urn; the ordinary type with a faucet at the bottom. About every 20 minutes the power goes on for about a minute to maintain the heat. There is an indicator light that is always on when the heat is right and goes off only for a minute when the power, to upgrade the water heat, is on.
a) Can I use the urn on Shabbos?
b) If I can, do I have to wait until the reheating power is off (or on) before taking out water?
A. Horav Shlomo Miller's Shlit"a opinion is that you can use the urn regardless of whether the light is on or not, as taking out water from the kettle does not have a direct effect in the temperature of the remaining water. (Although when there is a diminished quantity of water it tends to cool faster, and this may possibly trigger the thermostat sooner, it is still an indirect and uncertain outcome).
Rabbi A. Bartfeld as revised By Horav Shlomo Miller Shlit"a
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