How to use a tankless hot water heater in freezing temperatures

[Mox-co]

I am planning a work trip to eastern PA in March. My concern is the tankless hotwater heater may be exposed to below freezing temperatures. I was thinking of a heat lamp in the water heater area. I also looking for suggestions. What do you think?

 

[Martian]

I would be concerned about the entire water system, not just the water heater.

 

[Utclmjmpr]

That water heater does NOT have any water in it until activated ,BUT the water line TO IT is and can freeze as well as the rest of the water system..>>>Dan

 

[Utclmjmpr]

Check your system carefully,, many house furnaces will heat the under bays as well as the upper house area when activated ..>>>Dan

 

[Rene T]

That water heater does NOT have any water in it until activated ,BUT the water line TO IT is and can freeze as well as the rest of the water system..>>>Dan

I have a tankless water heater at home and it stays full all the time. The propane flame doesn’t start until there is movement of the water. That’s why it takes so long to get hot water at my faucets because all that cold water in the heater has to be displaced by heated water

 

[Lou Schneider]

I had an Atwood tankless heater that came with my Sunnybrook trailer. The manual said the flame would come on at a low level when needed to keep the heat exchanger coil from freezing. Worked until an unexpected cold snap while the trailer was in storage drained the propane. I replaced it with a conventional tank style heater.

 

[Gary RV_Wizard]

I have a tankless water heater at home and it stays full all the time. The propane flame doesn’t start until there is movement of the water. That’s why it takes so long to get hot water at my faucets because all that cold water in the heater has to be displaced by heated water

If it's tankless, what part is "full"? I think it's just the water feed, which is probably a coil (heat exchanger). I think that is what UT refers to in his post.

Whatever the semantics, there is a water line running through the heater than should have some freeze protection. It's probably not as exposed as a traditional tank-type heater, but don't ignore it.

 

[DonTom]

I replaced it with a conventional tank style heater.

I have been considering doing that in my 2022 Class A. How much hassle was it? Do you have any recommendations for replacing mine? It's a Girard GSWH-2.

IMAO, tankless water heaters are the stupidest things ever installed in an RV.

FWIW, I had a Takagi tankless at my old house in South San Francisco, which worked perfectly in every way.

I really like my water heater in my Y2K Class C. It is a simple six-gallon with a Hott Rod installed.

-Don- Reno, NV

 

[DonTom]

I have a tankless water heater at home and it stays full all the time.

The tankless at my old home in SSF had an electric heater that would come on when below 40° F. But it will not work well enough when very cold, they do not sell such here in Reno where we can have very cold winters.

-Don- Reno, NV

 

[Mox-co]

I have a tankless water heater at home and it stays full all the time. The propane flame doesn’t start until there is movement of the water. That’s why it takes so long to get hot water at my faucets because all that cold water in the heater has to be displaced by heated water

Yes, finally someone is thinking correctly. I'm not worried about the pex or the faucets since they are in the camper. The water heater is exposed to the outside temperatures and as stated in other threads, water in the small copper tube in the water heater can and will freeze and crack. So, what to do to prevent this??? is the real question.

 

[Mox-co]

The tankless at my old home in SSF had an electric heater that would come on when below 40° F. But it will not work well enough when very cold, they do not sell such here in Reno where we can have very cold winters.

-Don- Reno, NV

I will check, but I don't think there is such an electric heater in my application.

 

[Mox-co]

I would be concerned about the entire water system, not just the water heater.

It's PEX, not worried about the water lines

 

[Mox-co]

I had an Atwood tankless heater that came with my Sunnybrook trailer. The manual said the flame would come on at a low level when needed to keep the heat exchanger coil from freezing. Worked until an unexpected cold snap while the trailer was in storage drained the propane. I replaced it with a conventional tank style heater.

I'll have to check this feature, thanks

 

[Mox-co]

I have a tankless water heater at home and it stays full all the time. The propane flame doesn’t start until there is movement of the water. That’s why it takes so long to get hot water at my faucets because all that cold water in the heater has to be displaced by heated water

Yes it does, that is why it is preferred to blow air through it before adding antifreeze protection. Water is in the copper coil around a heat/flame tunnel, exposed to possible cold weather outside.

 

[Rene T]

If it's tankless, what part is "full"? I think it's just the water feed, which is probably a coil (heat exchanger). I think that is what UT refers to in his post.

When I said full I meant that the coil remained full of water until hot water is needed and it pushes out the cold water

 

[klook]

Most of the newer units have built in freeze protection by turning on when its to cold. You did not mention what brand you have and the age.

 

[woof-n]

I lived in a mobile home in northwest Ohio for two years. The hot water lines always froze first. Freezing is a real concern. Hopefully your heater has the freeze protection. An uncontrolled heat lamp may cause other problems, such as fires. I remember one fire in the park from thawing frozen water lines with a heat lamp. This story did not have a happy ending.

 

[klook]

Well if it does not have freeze protection, cover the door to insulate it a little and put a rough treatment 120v bulb in there. They give off more heat then light. Used to be what the old timers used in outside well houses up in the North. A 100 watt bulb is hot. They are an enclosed box so putting heat behind them does not work well.

 

[Mox-co]

Most of the newer units have built in freeze protection by turning on when its to cold. You did not mention what brand you have and the age.

Sorry, I am remote, 3000 miles away out of the country. It's a 2025 Jayco, if that helps.

 

[Mox-co]

Well if it does not have freeze protection, cover the door to insulate it a little and put a rough treatment 120v bulb in there. They give off more heat then light. Used to be what the old timers used in outside well houses up in the North. A 100 watt bulb is hot. They are an enclosed box so putting heat behind them does not work well.

That is what I was thinking, but didn't want to block airflow for when the propane tankless water heater comes on.