Heating a “plumbing cellar”
Our cabin (Maine island) is built on piers except for the “plumbing cellar”, an 8X8 ft. concrete block structure under the bathroom and kitchen which houses the electric hot water heater and pressure tank. I need to figure a way to keep pipes from freezing. There is no central heating furnace which would ordinarily does the trick in a real cellar. I could put a small cube heater down there, but they seem to use a lot of juice (1500 watts?), and would raise the temperature well above what it has to be (33F). I think I need a low capacity, thermostatically controlled heat source capable of heating a volume of about 512 cu ft (8 X 8 X 8). Is there such a thing?
Replies
cube heater + thermostat
Or, use a standard baseboard electric heater with a good thermostat. Finding the thermostat will be the hard part - you might have to look for a more industrial type one to have such a low set point. I'd aim for something like 40F.
Edited 11/29/2004 2:30 pm ET by Cairo
You are already capable of producing all the heat you need!
Setup a conventional hot water recirc system. Place a length of fin tube on the return in the cellar near the pressure tank.
How are you going to protect the lines outside the cellar? With recirc, you can wrap the hot and cold pipes together such that the hot line will keep the cold line from freezing.
You should be able to find a small electric heater with a built in thermostat, or simply install a wallmount thermostat to control the thing if you can't find one with a thermostat built in. 1500 watts really isn't that much, particularly if it's thermostatically controlled so it only runs when needed (it's about the same as running a hair dryer.) It would be better to run the heater on 240vac if you can, but 120vac is okay for heaters at 1500 watts or less. An HVAC supply house will probably have more to choose from than Home Depot. When I design these sorts of things I usually set the thermostat for 40 to 50 degrees, that gives you a little cushion above the freezing point. One good brand for small heaters is Berko, here are a couple examples from their catalog.
Baseboard heater: http://www.berkomeh.com/xprod_pdf/bulsub/ZBL-BKOWA.pdf
Here's a nice little wallmount heater: http://www.berkomeh.com/develop/prod_pdf/bulsub/ZBL-BcraO.pdf
A third possibility is to install self-limiting heat tape right on the pipes themselves and wrap them with insulation. This kind of heat tape doesn't need a separate thermostat, you just plug it in and forget it...it just comes on when needed. It also draws only a few watts per foot so the power demand is going to be pretty small. One good brand is Raychem. http://www.tycothermal.com/northamerica/english/heating/products.asp?can=1033&pt=mrk&pdid=110
Edited 11/29/2004 7:31 pm ET by Stuart
Thanks --- that's enormously helpful, as were the other responses to my query. We get occasional power outages when someone anchors on the submarine cable, so I probably should have a fossil-fuel backup for those cold, dark nights without electricity. I was thinking of a Coleman tent heater.
The water line from the well to the pressure tank is buried, probably not below the frost line of a wicked cold winter, and one local practice is to run a heating element into it, from house to pump. I think this is probably a job for a real plumber, but I'd like to learn more about it.
Tyco/Raychem also makes a heat tape that goes inside the pipe that actually looks pretty straightforward to install. The pipe does need to be insulated for this stuff to work.http://www.tycothermal.com/northamerica/english/heating/products.asp?can=1033&pt=mrk&pdid=790