Winterizing Tankless Water Heater (Using Nautilus Panel)

Tonemeister

Senior Member
Joined
Jan 12, 2012
Messages
120
Location
St. Thomas Ontario, Canada
Hello to all fellow campers! I am a little confused as to how to perform the winterization on our 2022 303RLS. I winterized our fifth wheel last November 2022 first by blowing air through the "City Water" hose inlet, and Nautilus panel set to "City Water", then opening ALL taps inside & outside RV (including toilet). I also opened the "Drain Plug Cover" on Tankless Heater as well to rid any water there. Using the "Winterize" settings on the Nautilus panel to suck antifreeze from a 10 Litre jug of antifreeze, I opened all taps & toilet until I saw pink. I have always had a 6 gallon water heater in our past RV's that I drained before winter, no worries. With the new Tankless heater I am concerned that if not winterized properly that any remaining water left inside water heater may damage the unit. Any tips would be greatly appreciated before cold weather sets in. Thanks for all replies in advance!
 
Hello to all fellow campers! I am a little confused as to how to perform the winterization on our 2022 303RLS. I winterized our fifth wheel last November 2022 first by blowing air through the "City Water" hose inlet, and Nautilus panel set to "City Water", then opening ALL taps inside & outside RV (including toilet). I also opened the "Drain Plug Cover" on Tankless Heater as well to rid any water there. Using the "Winterize" settings on the Nautilus panel to suck antifreeze from a 10 Litre jug of antifreeze, I opened all taps & toilet until I saw pink. I have always had a 6 gallon water heater in our past RV's that I drained before winter, no worries. With the new Tankless heater I am concerned that if not winterized properly that any remaining water left inside water heater may damage the unit. Any tips would be greatly appreciated before cold weather sets in. Thanks for all replies in advance!

Your procedure sounds right (I followed the one in the owner's manual). I start by blowing as much out of the system (with the red lever open on the Nautilus), and then follow that with the pink stuff. So far my tankless water heater has survived two New England winters (fingers crossed) with temps below zero. It is possible to isolate the water heater. Just be safe I pumped extra pink stuff in with the outflow opened to be sure there wasn't any water left.
 
Dont have the tankless... but we have always just set our Nautilus to "winterize", pump the RV freeze through our faucets/shower/toilet/outside sprayer(if used, but usually dont), drain the mains under the coroplast, and HW tank. Never had any freeze issues in 4yrs in MO winters (which get down to -10 or so).

Always felt that blowing out the water was over kill when using RV freeze. Our experience (when adding the RV freeze), it will mix with any left over water. We have been doing our chevy boat motors (which stay on our dock lifts all year) for 25yrs and never had any freeze issues.

But as always, do the steps that make you feel comfortable.
 
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I blow out the lines with compressed air, including the tankless water heater (drain it of any water first). I then pump the pink throught all taps, toilet and through the tankless heater. If you leave the water heater valve (Red one on Nautilaus) open, antifreeze will be pumped through the tankless heater when you open your firrst hot water tap.
 
I did the same procedure as you the first winter. I had to take the trailer back to the dealer for something else, I explained my procedure to the tech, he said I was correct. He opened the metal cover on the water heater and removed the 2 plugs and when he saw pink antifreeze come out, he said " good to go". I remove the plugs now,too. Probably not necessary, but no issues so far.
 
OK, I think I understand now. So to be clear....By "open" you mean to set the RED Nautilus lever to the 12 & 6 o'clock position (opposite position of "winterize"....but ONLY Red valve, other levers leave in "winterize" position)
Thanks again for your reply, really appreciate it!
 
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Does anyone have a tutorial on winterizing? I am a first timer with a tankless on my 2023 Imagine xls 23BHE
 
Try these You Tube video's:

Tankless Water Heater (from Grand Design):
https://www.youtube.com/watch?v=90Q3W1sHQqc&list=PLCtYmM3jEZr66hFs9-F0keYEB5olvgH3y&index=2&t

After following following above instructions, don't forget to turn red valve to the opposite "NOT WINTERIZE" position (pointing up) then turn pump back on to allow antifreeze to flow thru tankless water heater! (Other valves still remain in Winterize position, only red facing up!)



These are for a Water heater with tank, but still good to watch re: Nautilus system:

https://www.youtube.com/watch?v=-t_Gy92bn7k&list=PLCtYmM3jEZr66hFs9-F0keYEB5olvgH3y

https://www.youtube.com/watch?v=vkQcuPwuNHQ&list=PLCtYmM3jEZr66hFs9-F0keYEB5olvgH3y&index=3&t
 
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Hello to all fellow campers! I am a little confused as to how to perform the winterization on our 2022 303RLS. I winterized our fifth wheel last November 2022 first by blowing air through the "City Water" hose inlet, and Nautilus panel set to "City Water", then opening ALL taps inside & outside RV (including toilet). I also opened the "Drain Plug Cover" on Tankless Heater as well to rid any water there. Using the "Winterize" settings on the Nautilus panel to suck antifreeze from a 10 Litre jug of antifreeze, I opened all taps & toilet until I saw pink. I have always had a 6 gallon water heater in our past RV's that I drained before winter, no worries. With the new Tankless heater I am concerned that if not winterized properly that any remaining water left inside water heater may damage the unit. Any tips would be greatly appreciated before cold weather sets in. Thanks for all replies in advance!

This is my second year for winterizing my 2022 303RLS. No problems so far but what I would like to note is that if you want antifreeze in your TWH, you have to set the red Nautilus lever to the vertical position (Opposite of what it shows for the Winterize) if you want antifreeze to enter the water heater. I followed the procedure and used the "Winterize" diagram and couldn't get antifreeze out of the two TWH vent and drain. Once I switched the red lever to the City setting and left the others in "Winterize" it worked immediately. Now I realize that some may not want antifreeze in the water heater, but I am not taking any chances with the TWH and that extra chamber inside. I also found this same advice on some of the other forums and videos. Using the "Winterize" setting bypasses the water heater. Just a note.
 
Does anyone have a tutorial on winterizing? I am a first timer with a tankless on my 2023 Imagine xls 23BHE
View attachment 48888

I just did this on my 367BHS yesterday. Even after blowing air through the tankless HW heater, when I pumped antifreeze through I got about an additional liter of water pour out followed by pink stuff.....
 

Attachments

  • Winterization Checklist For GD with Furrion Tankless water heater.docx
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This is my second year for winterizing my 2022 303RLS. No problems so far but what I would like to note is that if you want antifreeze in your TWH, you have to set the red Nautilus lever to the vertical position (Opposite of what it shows for the Winterize) if you want antifreeze to enter the water heater. I followed the procedure and used the "Winterize" diagram and couldn't get antifreeze out of the two TWH vent and drain. Once I switched the red lever to the City setting and left the others in "Winterize" it worked immediately. Now I realize that some may not want antifreeze in the water heater, but I am not taking any chances with the TWH and that extra chamber inside. I also found this same advice on some of the other forums and videos. Using the "Winterize" setting bypasses the water heater. Just a note.

Agree, blowing out the HW heater does not get all of the water out of the mixing bowl. I got about a liter of water out before the pink stuff came out.
 
Just curious..... dont the tankless WHs have a low point drain valve like non-tankless WHs? Even our stick built tankless WH has a low point drain on it and we used to drain it each fall before buttoning up the house for winter.
 
Just curious..... dont the tankless WHs have a low point drain valve like non-tankless WHs? Even our stick built tankless WH has a low point drain on it and we used to drain it each fall before buttoning up the house for winter.

The Furrion Tankless water heater has a drain plug and a filter plug, lower right hand corner, behind the removable flash shield. Some water comes out when you remove them, more comes out when you blow air through, but there is still a mixing bowl on the back side of the unit about the size of a soft ball that does not empty by gravity or air (inlet and outlet to this "mixing bowl" are both in the upper hemisphere and air comes in and can exit without pushing out the water sitting in the bowl. Many horror stories in the forums about the water left in this bowl freezing and cracking the piping or bowl itself even though the unit had been winterized. People dewinterize their units after the winter and discover their HW Heater is a total loss with water pouring out the backside of the unit when they refill their water system.
 
The Furrion Tankless water heater has a drain plug and a filter plug, lower right hand corner, behind the removable flash shield. Some water comes out when you remove them, more comes out when you blow air through, but there is still a mixing bowl on the back side of the unit about the size of a soft ball that does not empty by gravity or air (inlet and outlet to this "mixing bowl" are both in the upper hemisphere and air comes in and can exit without pushing out the water sitting in the bowl. Many horror stories in the forums about the water left in this bowl freezing and cracking the piping or bowl itself even though the unit had been winterized. People dewinterize their units after the winter and discover their HW Heater is a total loss with water pouring out the backside of the unit when they refill their water system.

Wow.... wonder why they designed it that way? My stickbuilt TWH drains completely when I open the drain and pressure relief valves. Infact, I drain the entire central PEX water distribution manifold, lines and appliances using this method (my TWH is lowest hot/cold water drain point located in my basement utility room).
 
Don't know. First TWH I have ever owned. Maybe they had to change piping around to fit in the footprint of a standard water heater and it does not gravity drain anymore.
 
Easiest way is to run anti freeze through it, then pull the 2 drains on the outside of the TWH.

Easy and quick, no big deal.
 
I have read many posts about the Furrion tankless water heater freezing/failing after attempts at "winterizing". There are many posts (and videos) on the net about the "correct" procedure to do this, including some from so-called reputable sources. After careful study of the unit, I have come to the conclusion that some of what is posted is incomplete at best, and some is downright wrong at the worst. (There are some who have it right, I think.) I took the liberty to annotate a couple of pictures that may help some people see the issues and perhaps understand the solution.

RearSideAnnotated.JPG

FrontSideAnnotated.JPG

MixingBowlAnnotated.JPG


The are 2 places that may hold residual water, even after valiant attempts at winterizing:

1) The copper tubing in the lower portion of the heat exchanger.
2) The infamous "mixing" bowl.

Starting with the copper tubing in the lower portion of the heat exchanger, even after opening both the CW inlet screen and the so-called low point drain, water will remain in this lower portion. It is essentially designed as a big "water trap", as both the CW side inlet and the HW side outlet tubing are well above the remaining lower portion of the heat exchanger tubing. In my mind, the only way to purge this water is ...

1) Leave the Nautilus in City Water mode (eg do not bypass the water heater with the red valve).
2) Leave the CW screen in place. If you remove it, pink antifreeze will gush out making you think the tubing is clear, but alas it will not be since this opening is BEFORE the heat exchanger tubing.
3) Open the water heater HW side low point drain (the bottom most copper drain plug in the lower right of the front of the unit).
4) Pump antifreeze into the city water connection on the Nautilus until it flows out of the HW side low point drain. This will hydraulically purge ALL of the residual water out of the copper tubing.


Moving to the mixing bowl ...

1) Put the HW side low point drain plug back in. If you don't, none of the antifreeze you apply will push anything out of the mixing bowl. You will see pink antifreeze coming from this drain, but none of it will be going back up through the mixing bowl inlet pipe and purging the residual water there.
2) Open the nearest HW faucet (bathroom, kitchen whatever). You must purge the mixing bowl through this faucet.
3) Pump additional antifreeze into the city water connection on the Nautilus until 1-2 quarts of pink shows up in the sink with the open faucet. Don't count clear water, just good strong pink stuff. Unfortunately, you cannot do a true hydraulic purge of all of the residual water in the mixing bowl in this (or any other) way. This is due to the vertical inlet tube that empties into the mixing bowl near its top, creating a "dam" that holds water in the lower portion of the bowl. What you can do is use the mixing bowl to "mix" the antifreeze and the residual water in the mixing bowl to the point it is mostly antifreeze, and little water. The 2 are soluble, so they will mix and drop the freezing point of the residual fluid in the mixing bowl most of the way down to the antifreeze level, if not quite all the way.

Now you can remove both the CW screen plug and the HW low point drain plug if you want to drain some of the antifreeze out of the unit. There should be nothing but antifreeze left in the 2 "problem" areas at this point. Or, just leave it all in there.


Of course, an even simpler procedure to clear both trouble spots is to leave the HW heater in the system at the Nautilus (red valve up, City Water configuration), open just one HW faucet nearest the HW heater, pump the pink stuff into the city water inlet until a quart or 2 shows up in the open faucet sink. Don't count the clear water, just the strong pink colored stuff. This will purge all the residual water out of the heat exchanger copper tubing, as well as mix the residual water in the mixing bowl with enough antifreeze to "dilute" it to a low enough freeze protection point. I would do this LAST to avoid purging any residual plumbing system water back into the completed/protected HW heater.
 
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Your procedure sounds right (I followed the one in the owner's manual). I start by blowing as much out of the system (with the red lever open on the Nautilus), and then follow that with the pink stuff. So far my tankless water heater has survived two New England winters (fingers crossed) with temps below zero. It is possible to isolate the water heater. Just be safe I pumped extra pink stuff in with the outflow opened to be sure there wasn't any water left.

I winterized my Furrion just like you did and after 1st winter mixing bowl cracked and flooded my underbelly. I even stored mine in a building and it still cracked due to faulty design as they are discontinued: Hoping yours don't crack
 
I have read many posts about the Furrion tankless water heater freezing/failing after attempts at "winterizing". There are many posts (and videos) on the net about the "correct" procedure to do this, including some from so-called reputable sources. After careful study of the unit, I have come to the conclusion that some of what is posted is incomplete at best, and some is downright wrong at the worst. (There are some who have it right, I think.) I took the liberty to annotate a couple of pictures that may help some people see the issues and perhaps understand the solution.

View attachment 48964

View attachment 48965

View attachment 48966


The are 2 places that may hold residual water, even after valiant attempts at winterizing:

1) The copper tubing in the lower portion of the heat exchanger.
2) The infamous "mixing" bowl.

Starting with the copper tubing in the lower portion of the heat exchanger, even after opening both the CW inlet screen and the so-called low point drain, water will remain in this lower portion. It is essentially designed as a big "water trap", as both the CW side inlet and the HW side outlet tubing are well above the remaining lower portion of the heat exchanger tubing. In my mind, the only way to purge this water is ...

1) Leave the Nautilus in City Water mode (eg do not bypass the water heater with the red valve).
2) Leave the CW screen in place. If you remove it, pink antifreeze will gush out making you think the tubing is clear, but alas it will not be since this opening is BEFORE the heat exchanger tubing.
3) Open the water heater HW side low point drain (the bottom most copper drain plug in the lower right of the front of the unit).
4) Pump antifreeze into the city water connection on the Nautilus until it flows out of the HW side low point drain. This will hydraulically purge ALL of the residual water out of the copper tubing.


Moving to the mixing bowl ...

1) Put the HW side low point drain plug back in. If you don't, none of the antifreeze you apply will push anything out of the mixing bowl. You will see pink antifreeze coming from this drain, but none of it will be going back up through the mixing bowl inlet pipe and purging the residual water there.
2) Open the nearest HW faucet (bathroom, kitchen whatever). You must purge the mixing bowl through this faucet.
3) Pump additional antifreeze into the city water connection on the Nautilus until 1-2 quarts of pink shows up in the sink with the open faucet. Don't count clear water, just good strong pink stuff. Unfortunately, you cannot do a true hydraulic purge of all of the residual water in the mixing bowl in this (or any other) way. This is due to the vertical inlet tube that empties into the mixing bowl near its top, creating a "dam" that holds water in the lower portion of the bowl. What you can do is use the mixing bowl to "mix" the antifreeze and the residual water in the mixing bowl to the point it is mostly antifreeze, and little water. The 2 are soluble, so they will mix and drop the freezing point of the residual fluid in the mixing bowl most of the way down to the antifreeze level, if not quite all the way.

Now you can remove both the CW screen plug and the HW low point drain plug if you want to drain some of the antifreeze out of the unit. There should be nothing but antifreeze left in the 2 "problem" areas at this point. Or, just leave it all in there.


Of course, an even simpler procedure to clear both trouble spots is to leave the HW heater in the system at the Nautilus (red valve up, City Water configuration), open just one HW faucet nearest the HW heater, pump the pink stuff into the city water inlet until a quart or 2 shows up in the open faucet sink. Don't count the clear water, just the strong pink colored stuff. This will purge all the residual water out of the heat exchanger copper tubing, as well as mix the residual water in the mixing bowl with enough antifreeze to "dilute" it to a low enough freeze protection point. I would do this LAST to avoid purging any residual plumbing system water back into the completed/protected HW heater.

Three easier ways to remedy the faulty design is:
1. Class action suite against against G.D. to replace all Furrion tankless HWH.
2. Put a drain in the low part of the mixing bowl.
3. Ounce it cracks take the mixing bowl out and toss it.
 

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