Heat tape and pipe insulation

Beeman · #1 07/12/08, 03:43 PM

Seems pretty funny to ask this when it's 90* out but what better time to work under the house where it's cool.

I just did some plumbing under the house and cleaned off the fiberglass insul that was laid over the main water feed pipe. The pipe is 3/4" PVC which lays on the dirt under the house until it goes up in the middle of the house. I've heard about commercial heat tape that can be bought/cut to length and doesn't have a thermostat like the ones you buy in the hardware store. Anyone use or heard of this? If you were heat taping the pipe what insulation would you use? I've only used the hardware store heat tapes and just taped them to the pipe. I've not had any pipe freezing problems in a long time, but then again it hasn't been real cold in years. I did freeze a pipe when the underpinning had gaps and the pipe ran up in the air under the house.

ldc · #2 07/12/08, 04:24 PM

Beeman, years ago in NJ, there was a crawl space over a deep dirt pit basement, and the water pipes crept out to the far ends of the house thru the crawl space. We used the tape (tied it on w/ string and duct tape loosely at intervals), and we put fiberglass batting under the piping, so that the pipes weren't sitting on the cold flooring of the uninsulated crawl spaces. This flooring was both wooden and rock. We had some very cold yrs at the end of the 70's, but this system never failed us: it kept the pipes at 55 degrees all the time we needed it to be that. The house was heated by a huge wodstove, otherwise. This tape didn't have a thermostat, but we tested it w a thermometer to get the 55 reading. I admire your fortitude to get under the house, but you are RIGHT; this is the time of year to do it! I think it's a great prep. ldc

Danaus29 · #3 07/12/08, 06:58 PM

We have heat tape that can be burried. It's held on to the pipe with zip ties and covered with Great Stuff foam in a can insulation. I know you can get the wire and cap from Grainger because that is where dh found it. What exactly it is called I don't know. I wonder if the heat cable for soil heating in greenhouses would work just as well.

It's a great idea to do that kind of work now. No sense in waiting until your pipes are froze and split before thinking about keeping them from freezing.

agmantoo · #4 07/12/08, 08:20 PM

Yes, I have used the product you described, hundreds of feet of it. It holds up extremely well and I have never had one to burn out. The design is such that the heat is conducted from one lead to the other cross ways in the wire. The heat tape appears like the old tv antenna wire and the conduction is through the flat between the two wires. Making connects to a pig tail cord is rather difficult and the wire is difficult to skin for electrical connections. It is best IMO to use a small terminal strip and connect the heat tape to the electrical wire using screws. I would still put a line thermostat on the power feed to conserve power when the temperature is above freezing. I am frugal! Here is the product http://www.chromalox.com/productcata...ils.aspx?p=355
I have become a Pex convert. Usually it can freeze and thaw and with its memory return to normal. It is amazing to watch the pex when heated and later as it cools, fantastic stuff. I am converting some of my rentals to pex as they need repairs.