Protecting 4" pipe to water tank from freezing

[KineticoUser]

I was finally able to replace my leaking 10K gallon water tank this year. When I attempted to reinstall the heat cable on the 4" inlet, I noticed it was broken. I went online to get a new one and noticed they all say they are for pipes 2" and thinner. Is it worth it to spiral run a heat cable around a 4" pipe, or should I just add 2" of fiberglass/closed-cell foam insulation and cover with 20mil pipe wrap? Since heat cable tends to overheat if covered by more than 1/2" of insulation, what if I limit the insulation on top of the sensor and add extra insulation on the rest of the cable?

 

[KineticoUser]

Since no one's responding, does that imply a 4" pipe doesn't need protection? If you do protect your pipe, how do you do it, and what's your reasoning behind your choice?

 

[Sponsor]

 

[Reach4]

Given that you have a 10000 gallon tank with a 4 inch outlet , I suspect you are in California rather than Alaska or North Dakota.

I would think that if the heat sensor is under the insulation too, if there is any overheating, the sensor would cut power to the heat tape/cable. I am not a pro.

I am suspecting that is an outlet rather than an inlet, because I would think an inlet would be empty during hard freezing weather.

 

[KineticoUser]

Thank you for your response. It's both inlet and outlet, and I am in California. Here is what it looks like: https://photos.app.goo.gl/siabaPBGnRN2PWrn6

I misspoke about the heat cable overheating if insulated. The opposite is actually what happens. The thermostat may not sense the need for heat (if too insulated), and the pipe may freeze. I believe that taping the sensor to the pipe without insulation while adding extra insulation on the rest of the pipe may keep the pipe warmer. I am thinking of putting 1" of fiberglass insulation over the cable (not the sensor) and then covering that with 1" of closed cell foam insulation and then covering that with 20mil pipe tape.

Frost King, which has a 7wt cable says it is only to be used on pipes 2" or less in diameter. Here is another option that only puts out 3-5wt, claims it can be used on pipes up to 6" in diameter and can also be crossed over itself. https://radiantsolutionscompany.com/product/pipe-freeze-pro/ It also recommends covering with foam (which other companies and governmental agencies recommend against) and costs twice as much. Help me to understand the reasons a 7wt cable can't handle more than 2", while a 3-5wt cable can handle 6".

 

[Reach4]

My thinking is that if you can keep one side of the pipe unfrozen, the other side of the pipe icing up may not be a problem. So I would think that a full spiral is not needed. I am not a pro.

Insulation wise, I think you would want to not have insulation between the sensor and the pipe. But insulation that covers both should be fine IMO.

 

[Blue Oaks]

Two questions: Is the tank in the sun during the day? How long is the 4" pipe? That amount of water is a pretty good sized thermal reservoir. I don't think you'd see freezing at least up to a couple feet away from the tank with just some insulation wrap. Can you bury the 4" pipe?

Oh, and what's your elevation? I'm at 700 feet and don't worry a lot about freezing, but I don't have much above ground either.