heat tape and pipe insulation questions


Old 01-19-09, 04:52 PM
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Join Date: Dec 2002
Location: Pittsburgh, PA
Posts: 553
heat tape and pipe insulation questions

I have one 4' section of 1/2" copper exposed in my garage. Before I bought the house 23 years ago, there was evidence of a frozen pipe and the former owner had put heat tape on it... and a real crappy job at that! I removed it 22 years ago and put low density polyethylene insulation around it and then installed an insulated garage door, I have never had any problems.

Last summer I cut those lines and installed a pressure regulator and a bypass valve so a redo was in order. With the recent sub zero temps here in PA, I'm getting a headache from running the kerosene heater all night in the garage. So far I have not seen temps lower than 42 degrees without the heater running but I don't want to chance it.

Today I installed a 3' piece of thermostatically controlled heat tape. The instructions said to tape it to the pipe with electrical tape good for > 176 degrees F which I did. It then said to wrap with 1/2" fiberglass insulation which I also did. In order to make it look pretty, I reinstalled the celulose insulation over top of the fiberglass insulation and heat tape. I then loosly strapped it with zip ties since I had a few small wires to fasten to it. I did not clamp it tight enough to completely close the slit in the preformed insulation.

Do you see any problem with putting the polyethylene. insulation over top of the whole works? I would think that if the heat from the heat tape won't melt electrical tape, it won't hurt celulose insulation, especially if it was the second layer. BTW, my tape is 17 watts per foot. I' m only concerned because they specifically called out wrapping with fiberglass insulation.

UPDATE: I found a website that calls out normal temperature range to +210 degrees F. If they call for electrical tape that withstands 176 degrees, I might be OK???

Last edited by HotRod53F100; 01-19-09 at 05:07 PM.
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Old 01-19-09, 05:49 PM
Join Date: Oct 2008
Location: New England
Posts: 9,995
Here's my take on heat tapes. If they do not have a thermostat, then they simply produce heat, heat, and more heat. In a perfectly insulated box, the temperature will rise to, well much hotter than you want. So when they call for fiberglass insulation, which is noted for allowing air to flow through it, I would not think it good to add more and more insulation. All you want to do is keep the pipe from freezing and without thermostatic control, the extra insulation is simply raising the temp where more is no longer needed and too much will cause a fire.

If there is a thermostat wrapped in with that tape, so that the temp is well controlled, then perhaps it would save a bit on your electric bill. But best to follow the mfg recommendations.

For future reference, there is a heat wire (Available at HD) that is internally temperature controlled at a max of 3 watts per foot that you can wrap up 100% as it will self regulate and only heat when needed. Fire proof essentially. My choice.

Old 01-19-09, 06:18 PM
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Join Date: Dec 2002
Location: Pittsburgh, PA
Posts: 553
I think that this is the same brand that HD sells... EasyHeat. I had to buy it elsewhere because they don't stock a 3' model. I'm not sure but I think that the opposite end from the thermostat may have a sensor, they made sure to say that the thermostat AND the opposite end must be secured to the pipe.

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