Frozen Hot Water

Tbekkelund

New Member
Joined
Dec 17, 2024
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7
I am having a problem with my hot water freezing up in temperatures below 30 degrees. I'm kind of stumped on this one so hoping someone can help. I live full time in my new to me 2018 Reflection 297RSTS. I am connected to city water, my hoses are wrapped and have heat tape. I have cold water out of every faucet but no hot water. I can turn on hot on all faucets and I get nothing, turn on hot and cold on any one faucet and it back flows cold water through the system and I get cold water out of any faucet that has hot only turned on. That tells me that the hot water lines between faucets isn't frozen. I can open the pressure relief valve on the tank and I get a steady flow of water. Shut off the supply and water stops from the pressure relief. This tells me that I have a good supply to the water heater and that isn't frozen. It seems that the problem may be beneath the floor where the hot water is dispersed to all of the fixtures. I have ran my heater duct to the opening in the floor where the plumbing penetrates and let it run for about 2 hours, enough for the inside of the camper to reach 80 degrees and still have no hot water. I have reached my hand through the Coroplast under the camper and I feel the heat from the heater. I hope I am describing this well enough. I am out of ideas of what the problem could be. Any ideas?
 
I had the same symptoms after a cold night a few weeks ago. The real clue for me was that the cold water wasn't frozen, so it didn't make sense that the hot water would be. After reading similar posts here and at other websites I took an educated guess that the check valve went bad and the fact that it was cold outside was just a coincidence. It was a weekday and I was able to find a camper dealer about 30 minutes away that had a check valve in stock. I replaced the existing one and sure enough it now worked. The only oddity is that the old valve seemed to be in fine shape. No internal components were broken and I could push the plunger/spring system with ease and it would return to closed when released. I'm wondering if there was some debris that got knocked loose when I took it out. I didn't take any chances though and threw it away as they are relatively inexpensive.
 
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If what @Timmer suggested doesn't turn out to be the issue, then perhaps look closer at your low point drains as @Jims94vmx suggested. Mine would freeze at about 20 degrees until I moved the low point drains up higher and then insulated them with a rigid foam frame and cover that I now have to remove to drain. It adds a step to winterizing processes but it doesn't freeze up like it did before. Also, I always use the furnace in cold weather to ensure the belly is getting some heat, but it sounds like you have a different method to accomplish that.
 
I only had problem when I replace Tank with tankless(forgot to drain tank and it cracked). I would open the drawers below cabinet to allow warm air into tank /piping area. That area isn't insulated very well due to water heater cutout.
 
Just a little bit more info. The guy that I bought it from removed all of the cabinetry from around the water heater so all of the plumbing and back side of the unit is exposed. There is a heating duct that blows directly on all of this plumbing. I believe he also replaced some of the piping off of the water heater because parts of it are pex and other parts are a softer rubber like hose. I don't see any kind of check valve in any of that plumbing so not sure if it was removed from the system. Would the check valve be in another location or should it be right there at the tank? I will check the low point drains and try to get some heat on them somehow.

You guys have been a great help so far, I appreciate the advice.
 
I don't see any kind of check valve in any of that plumbing so not sure if it was removed from the system. Would the check valve be in another location or should it be right there at the tank?

I would expect you have one. Mine was connected directly to the water heater. It could easily be mistaken for just a connector between different size/types of threads. It's male threaded on both sides so probably around 3/4" is showing when installed.

Here is the one I replaced with a brass one - Check Valve
 
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Great news!!! I just got home from work and have hot water again. I came home at lunch time and looked for a check valve at the water heater but there isn't one on it. It does have a 2 inch nipple coming out of the tank that the pex fitting connects to. I took it off to verify it wasn't a check valve. More than likely the previous owner took it off and couldn't get another one locally because of our location in Alaska so he replaced it with a regular nipple. I checked both low point drains and the cold ones were fine but both hot drains were plugged with a slug of ice. I didn't think that would have caused it to freeze all the way up into the main pipe but I shoved them up into the belly as far as I could and figured I'd deal with it more tonight. Low and behold, got home just now and I have water flowing again. Now to insulate the drains better!!!

Once again, thanks for all of the great help. I'm glad I searched for this forum last night. I'm sure I will have plenty more questions in the future.
 
Glad to have helped. Been there before. Doesn't hurt to shorted a couple inches and seal better. Also get at least that end off the Coloplast to allow heat to get around water lines. Have fun.
 
I am having a problem with my hot water freezing up in temperatures below 30 degrees. I'm kind of stumped on this one so hoping someone can help. I live full time in my new to me 2018 Reflection 297RSTS. I am connected to city water, my hoses are wrapped and have heat tape. I have cold water out of every faucet but no hot water. I can turn on hot on all faucets and I get nothing, turn on hot and cold on any one faucet and it back flows cold water through the system and I get cold water out of any faucet that has hot only turned on. That tells me that the hot water lines between faucets isn't frozen. I can open the pressure relief valve on the tank and I get a steady flow of water. Shut off the supply and water stops from the pressure relief. This tells me that I have a good supply to the water heater and that isn't frozen. It seems that the problem may be beneath the floor where the hot water is dispersed to all of the fixtures. I have ran my heater duct to the opening in the floor where the plumbing penetrates and let it run for about 2 hours, enough for the inside of the camper to reach 80 degrees and still have no hot water. I have reached my hand through the Coroplast under the camper and I feel the heat from the heater. I hope I am describing this well enough. I am out of ideas of what the problem could be. Any ideas?
**** Me too! My D-I-Y heated water hose not good enough for 18 degree weather here Ozark Lake Missouri. (Feb 13, 2025). I've borrowed a manufactured one temporarily and have cold but no HOT water. Tomorrow warmer. Pray HOT water working. I'll look into the "check valve" issue others have spoken of. I have 2023 GD "Imagine" travel trailer 32ft. ****
 
**** Me too! My D-I-Y heated water hose not good enough for 18 degree weather here Ozark Lake Missouri. (Feb 13, 2025). I've borrowed a manufactured one temporarily and have cold but no HOT water. Tomorrow warmer. Pray HOT water working. I'll look into the "check valve" issue others have spoken of. I have 2023 GD "Imagine" travel trailer 32ft. ****
Since my last post, it has become a regular occurrence for me. I did find that the problem is indeed the low point drains. Every couple of days, when the temperature is in the 20s and below, I have to go out, take the caps off the low point drains, and hit them with a heater gun until water starts to flow out. I do them one at a time, starting with the ones closest to the inlet. When I clear one, I shut the water off, reinstall the cap, turn the water back on, and do the same for the remaining 3. Sometimes it is only the hot, and sometimes they all freeze. It usually takes me about 5 minutes to clear them all with a really good heat gun. As soon as I get a day off, I will cut them shorter and build an insulated box over them. Hope this helps and you get hot water soon.

PS, I did talk to the previous owner and he did remove the check valve because it failed. Apparently when it failed, pieces of it went through the hot water system and it seems like there is a blockage somewhere before the kitchen sink because I have low flow on the hot side only in the kitchen.
 
Since my last post, it has become a regular occurrence for me. I did find that the problem is indeed the low point drains. Every couple of days, when the temperature is in the 20s and below, I have to go out, take the caps off the low point drains, and hit them with a heater gun until water starts to flow out. I do them one at a time, starting with the ones closest to the inlet. When I clear one, I shut the water off, reinstall the cap, turn the water back on, and do the same for the remaining 3. Sometimes it is only the hot, and sometimes they all freeze. It usually takes me about 5 minutes to clear them all with a really good heat gun. As soon as I get a day off, I will cut them shorter and build an insulated box over them. Hope this helps and you get hot water soon.

PS, I did talk to the previous owner and he did remove the check valve because it failed. Apparently when it failed, pieces of it went through the hot water system and it seems like there is a blockage somewhere before the kitchen sink because I have low flow on the hot side only in the kitchen.
**** Puzzled. How would frozen low point drains affect lack of hot water? ******
 
Perhaps I should have asked more clearly . . . how would frozen low point drains affect lack of hot water at bath &/or kitchen faucet?
Oh okay, so the issue with the low point drain is actually the cold air that has a direct path to the water line via the exposed tubes. They have a common tendency to be the first place where freeze ups occur above the valves and where they "T" off the main lines.

Edit: Oops, just saw that @18CrewDually answered that too.
 
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You have 4 low point drains? All of my RVs have only had two.
Yep. I can't figure out the schematics of it but there is a hot and cold right under the water control panel, and another hot and cold about 4 feet back in the proximity of the water heater.
 

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