Pex heating to prevent frozen pipes?

Old 01-07-18, 07:16 AM
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Pex heating to prevent frozen pipes?

I have a 300 year old house, and the supply lines in the basement run through a cold crawl space- Iím pretty sure this is a problem area for freezing pipes and I am going through the crisis of no water right now. The lines that freeze are probably PEX and are otherwise copper. Would it make sense to use PEX radiant heating supplies to run a third pipe alongside the supply lines to prevent this in subsequent winter or is this a hazard or waste of resources?
Old 01-07-18, 08:33 AM
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I think you would be better off using heat tape and insulating the pipes.
Old 01-07-18, 11:57 AM
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Neither copper nor PEX bare unheated piping are satisfactory to run through freezing spaces. Copper will split longitudinally due to the expansion of water when it freezes. PEX will bulge, maybe not split. Steel pipe is less prone to splitting than either copper or PEX, but still not impervious. Heat tracing tape would work for the copper, but might overheat the PEX? Another approach is to insulate and heat the crawlspace or to relocate the pipes.

Your house is really 300 years old? Pre revolutionary war?
Old 01-07-18, 12:34 PM
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Oh thatís a new one. Some here in Pa. go back to 1680ís.
Old 01-07-18, 01:01 PM
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Anything that might potentially freeze I'd want to see in PEX. Preferably you do that in one continuous run without fittings. PEX is very capable of stretching with the pressure of expanding ice but the brass/plastic fittings are not.

I have not tried heating PEX. Being plastic it doesn't conduct heat as well as steel or copper so I'd do some research before trying to heat it. Most heat tapes are not well controlled so you could see some temperature spikes especially if you insulate over it.
Old 01-09-18, 10:19 AM
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Yep, it's old!

The home dates back to 1717, unless it is older. Still working on getting more records!
I am hesitant to use heat tape, because I can see in a copper application where it might help by conducting heat across the pipe media and thawing the water, but I would think it is too concentrated to work on something like PEX. I can't keep the space heated- there are too many air leaks in the space, and not enough access- the freezing space is the crawl space, and placing a heater would block access to it. My only way to heat it is to place a propane heater in the out part of the basement and direct the heat toward the crawlspace. The reason for adding the radiant piping would be to put a gentle heat source near the existing pipes, which look to be a mixture of copper and PEX, depending on where it routes to. I think I have the answer- it looks like an expensive project that would not pay off (Existing PEX is just the pipe crimped on to copper adapters- no manifolds, which looks like another $250 expense.) I'll leave it how it is for now and see if it freezes again- I'm suspecting there was an issue with the pump brought on by cold temperatures, perhps a relay getting to cold to flip or something. The easy solution to that will be to heat the space if it happens again... or just try tapping the connection box on the pump. Thanks for the responses though!
Old 01-09-18, 01:35 PM
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This is just a thought.

Your pipes are freezing because I'm guessing you have that zone shut down or very low to save money.

As a general rule moving or circulating water does not freeze.

Years ago when the price of oil went through the roof people in my area started burning wood which was fine until they found out where some of their heating pipes were located and although the living space was warm, people who had pipes in locations like yours experienced frozen pipes.

Back then what I found was an independent senor, for lack of a better word that tied directly into the pump bypassing the burner circuit. It had a sensing bulb that was located outside and depending on how cold the temp was the sensor turned on the pump to circulate the water. It was a time and temp control so we'll say at 0 it might turn the pump on every 10 min. for so long and then shut it down.

The warmer the temp, the less it ran.

I don't know if they are available anymore but I would imagine any timer with an on/off switch would suffice, especially in this cold weather.

Just a thought.

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