From: nojunk@knology.net   
      
   On 2/23/2018 4:55 PM, etpm@whidbey.com wrote:   
   >      My shop is a steel building similar to a quonset hut. The pipes to   
   > my bathroom sink run down inside one of the deep corrugations. The   
   > bathroom walls are covered in drywall which in turn is covered with   
   > thin sheets of vinyl covered Masonite.   
   >      I insulated the pipes before covering them with the drywall. I   
   > then put insulation down inside the corrugations to insulate the   
   > walls. But I think some rodents got into the insulation. Whatever   
   > happened when the temp drops below about 30 degrees the bathroom pipes   
   > will freeze.   
   >     I am not eager to tear into the wall to find the problem. So I   
   > leave the taps slightly dripping when the weather gets too cold. I now   
   > have a little water heater under the sink so that the main water   
   > heater is off most of the time. I turn off the under sink heater when   
   > the tap is dripping.   
   >     So my system works except when I forget to leave the water   
   > dripping. And I did that yesterday.  Coming in to work this morning I   
   > discovered the frozen pipe problem. Besides the hassle of no water one   
   > day the pipes are going to burst and then I WILL need to tear into the   
   > wall.   
   >     But maybe I have hit on a solution. The water pipes going into the   
   > main water heater are connected to each other with a heavy copper wire   
   > just before the heater connections. This is to comply with the   
   > building code.   
   >     So I figured if I connected some power to the pipes right at the   
   > wall stops I could maybe get them to heat up enough to thaw them. I   
   > measured the resistance from stop to stop and it was 4 ohms. The stops   
   > are plumbed to the sink taps with plastic pipe so I know the   
   > resistance I measured was through the supply pipes.   
   >     So I plugged in a Variac, plugged my battery charger into the   
   > Variac, and connected the battery charger leads to the wall stops.   
   > Then I dialed up the voltage until the charger was putting out about   
   > 18 amps. Checking about an hour later I see water is now flowing from   
   > the taps.   
   >     So now I need to wire up a transformer controlled by a thermostat   
   > to keep those in wall pipes warm. No more dripping taps!   
   >       Anybody want to tell me why this is a bad idea?   
   > Thanks,   
   > Eric   
   >   
     At one home I had built, I put a return pipe on the kitchen sink   
   hot water pipe. The return went back to the bottom of the water heater.   
   Hot water would rise to the kitchen sink and cooler water dropped back   
   to the bottom of the water heater. So I always has immediate hot water   
   at the kitchen sink.   
     I don't know if you have access to connect something like that.   
   But it was nice while we had it. It's a little wasteful, but I suspect I   
   spend more dumping water down the drain waiting for hot water.   
      
      Hey, How about a small thermostatically controlled  pump between the   
   hot and cold pipes under the sink. Pump hot water into the cold water   
   pipe whenever the temp is below freezing and maybe a 5 minute turn off   
   switch for when you want cold water but the temp is below freezing.   
   Would take much of a flow rate.   
                                      Mikek   
      
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