Winterizing tankless water heater

[Frosty68]

First time winterizing my Reflection 315RLTS. My question is how to winterize the tankless water heater. I've seen some videos bypassing, using air, using rv antifreeze so I'm wondering what the forums opinions and metods you all use. I don't have an air compressor to use air to blow water out of water heater so is there a method to use that doesn't require a compressor? Thank you.

 

[Scott'n'Wendy]

I don't believe there is a way to successfully use air to winterize a tankless water heater. AF is the only way.

 

[huntr70]

Do not bypass, pump AF through it and go about normal business.

 

[reubenray]

I am thinking about doing this myself this year, but I am concerned I will do it wrong and I have frozen pipes.

 

[Frosty68]

I'm afraid of doing it wrong as well. The rest seems straight forward but I've seen videos where they use air to remove water from heater, then AF, but I have a nautilus system and not sure if heater is getting bypassed in winterize mode or not.

 

[Wichita Dave]

Here is how I do my 2022 280RS. If you don't have air, just drain as best as you can.

Winterize 2022 280RS with tankless water heater and black flush line​

I just did this again for the third season in a row. No issues even with the mixing bowl. I got pink through the heater mixing bowl too.

This year I cut a 4" hole (10" from outside edge, 10" from floor) in my pass-through barrier so I could reach in and snap-turn the heater over-pressure valve.

- Managing pressure on the blowout adapter
I use a purchased air blowout adapter to which I've added a ball valve and a cheap pressure regulator. That way I can run the compressor/tank in the garage at full pressure and have control at the point of use. I set the regulator to 20 PSI, open the valve (the pressure drops to zero) then turn the regulator until I get 20 PSI again.

Reference: These are the openings I let air and anti-freeze through (not listed in any particular sequence).

- rear of trailer quick connect cold water fitting
- Nautilus P1 panel hot and cold valves/quick connect
- low point drains
- sink valves hot and cold
- shower valves hot and cold (and the shower hose)
- toilet flush valve
- water heater heat exchanger inlet strainer
- water heater heat exchanger drain plug
- water heater over-temperature valve and drain tube
- black tank flush (there is a backflow preventor under the bathroom sink and the hose segment from it to the black tank has a low point laying on the floor behind the pass-through barrier)

- also open and close the fresh water tank drain gate valve to be sure there is not water standing on top of the gate.
- catch anti-freeze pushed through the lines in a bucket to pour into the black tank.
- pour fresh anti-freeze to fill the sink and shower drain traps.

-Begin the procedure
With the P1 panel set to "City Water" I connect the blowout adapter to the white city water connection. I use heavy yellow Teflon tape on the hose connection threads.

- insert a quick connect fitting (Valterra PF247007 Quick Connect Hose Adapter or the coiled hose furnished with the trailer) to the rear quick connect fitting.
- managing the pressure on the blowout adapter, push air and water out of the trailer rear end.
- close the blowout adapter valve and let the compressor tank pressurize.
- open the faucet valves inside the trailer.
- open the low point drains.
- managing the pressure on the blowout adapter, push air and water through the open valves and drains. Remove the connector from the trailer rear.
- close the blowout adapter valve and let the compressor tank pressurize.
- close the inside valves.
- close the low point drains.
- managing the pressure on the blowout adapter, I ask my wife to step on the toilet flush valve while pushing air and water through it.
- connect a hose to the Nautilus P1 panel quick connect and open both valves pushing air and water through them.
- close the blowout adapter valve and let the compressor tank pressurize.
- close the Nautilus P1 panel quick connect valves.
- open the water heater inlet strainer and drain plug
- managing the pressure on the blowout adapter push air and water through the hot water heater.
- put the strainer back in (loosely)
- snap the over-pressure valve (repeatedly)
- close the blowout adapter valve and let the compressor tank pressurize.
- close the drain plug (loosely)
- open the low point drains again

Reference: Nautilus P1 panel user instruction manual
The section titled: "Winterizing Plumbing Lines and Fixtures"

-Continue by using the P1 manual "Winterize" instructions
- set the P1 panel to "Powerfill" and the panel valves (not the black one) to 45 degrees.
- managing the pressure on the blowout adapter push air and water through the low point drains.
- close the blowout adapter valve. Disconnect the blowout adapter.
- set the P1 panel to "Winterize".
- close the low point drains.

-Reference (and the black tank flush air blow out)
- I use a full-hookups site before arriving home to clean the black tank and drain the tanks.
- before pumping anti-freeze into the trailer I use a five gallon bucket to drain anything remaining in the tanks. I use a lid if transporting this bucket from storage 8>).
- leave the black tank dump valve open.
- connect the blowout adapter to the black tank flush.
- managing the pressure on the blowout adapter push air and water through the black tank flush.
- close the blowout adapter valve. Disconnect the blowout adapter. I am finished with the air.
- close all of the dump valves.
- open and close the fresh water tank drain valve.
- shake the anti-freeze bottles to mix any solids that have settled out.

- pump anti-freeze through the trailer.
- anti-freeze will not be pumped through the water heater during this procedure!
- I ask my wife to switch bottles as I open and close the same quick connects and inside valves (hot and cold) including the toilet (but exclude the heater because it is not in the circuit). Close the valve or quick connect when you are sure only anti-freeze is coming out.

- I do the longest lines first starting at the rear quick connect.
- catch the anti-freeze in a bucket. When finished I pour it into the black tank.

-After the Nautilus P1 manual procedure is complete: winterize the heater and black flush using a manual plunger pump
- set the P1 panel to "City Water".
- open the hot water heater inlet strainer and drain plug.
- using a manual plunger pump, push anti-freeze through the heater (with the trailer lines full of anti-freeze, it has nowhere else to go).
- close the strainer first (tightly) and push more anti-freeze through the drain plug.
- close the drain plug (tightly).
- I ask my wife to use the manual plunger pump (pull the handle and put a static pressure on the plumbing) and I snap the over-pressure valve (repeatedly) until I see pink coming out of the drain tube. That means there is anti-freeze in the mixing bowl. The mixing bowl is the most difficult item to winterize, so extra effort/time for this step is worth the effort.
- use the manual plunger pump to push anti-freeze through the black tank flush line.
- pour anti-freeze into the sink and shower traps.
- wipe up any excess anti-freeze to prevent stains.
- flush the manual plunger pump with clean water.

This is what I do. I think it is comprehensive. I haven't had any issues. Your comments are welcome.

 

[txloser]

I never feared or was bothered by winterizing when I had a standard WH. I’m not gonna lie, now I’m a little intimidated about the complexity of winterizing the Furrion tankless. lol.

Great write up. The detail and time you put into this is great.

 

[Wichita Dave]

I had posted that on another forum last year. I re-read it last week before I winterized. So I just copied and pasted it here after I saw the questions about it. Just sharing my notes ...

 

[ronsbh]

First time winterizing my Reflection 315RLTS. My question is how to winterize the tankless water heater. I've seen some videos bypassing, using air, using rv antifreeze so I'm wondering what the forums opinions and metods you all use. I don't have an air compressor to use air to blow water out of water heater so is there a method to use that doesn't require a compressor? Thank you.

I don’t have a compressor either but I use an air tank that I bought at Harbor freight. I follow the GD instructions to winterize, open the drain and filter to the on demand water heater and blow air through it. After blowing air through everything I then add the AF to all the water lines and then add about a cup to each P trap and commode. Like I said I follow the GD instructions from the manual and haven’t had a problem.

 

[Wichita Dave]

General Reference:
Here is the plumbing schematic for the P1 Nautilus panel in my 2022 280RS:

https://www.bandbmolders.com/wp-content/uploads/2024/03/P1-Nautilus-Schematic.pdf

 

[txloser]

So in theory to get antifreeze into the WH you could do the winterize configuration but leave the red knob in the city configuration? I’m fairly certain my Solitude is the same but I’ll have to open a book to see

I often times just blow out the system in past RV’s here in Texas. Only doing antifreeze for the longer periods of low temp, but I thought I read somewhere you can damage the Furion with air pressure.

Edit: I decided to RTFM. Looks like for the Solitude it’s a 3 handle nautilus, so completely different, but the instructions are surprisingly helpful specifically for the Furion tankless. Biggest takeaway was no more than 30psi for the WH, 40psi for the rest.

 

[Wichita Dave]

@txloser, after looking at the P1 panel diagrams, what you suggest seems like that would work! I will review that again in the Spring mid-March when I winterize after my return home from Texas.

 

[Mechanic Bob]

Reference to the Tankless Water Heater:

I turn the Switch off
Remove the Fuse
Remove the the screen (Plastic knob)
Remove the Brass drain screw
Open the low point drains
Blow out the lines
Replace the Low Point plugs, replace the two Water heater items.
Then fill the entire system with RV Antifreeze.

 

[OshawaDave]

Do not bypass, pump AF through it and go about normal business.

Right on. The information is included in the coach manual. I just winterized yesterday. Drain the tankerless heat by removing the brass drain plug. (I use compressed air then AF)......then pump AF through everything. Just remember to keep the water heater valve open.

 

[CedarCreekWoody]

Be aware there are multiple brands and some require draining, some do not. Download the manual for your specific model. My Girard has no drain.

 

[BoredWeasel]

Furrion says compressed air followed by antifreeze

 

[BillandLisa]

Great post Wichita Dave. This post also has some marked up photos illustrating the issue. Winterizing Tankless Water Heater (Using Nautilus Panel)

 

[COGrandDes]

Furrion says compressed air followed by antifreeze

Totally agree. I thought it was super easy actually.....there are plenty of posts with pics and instructions.

 

[DohMan]

First time winterizing my Reflection 315RLTS. My question is how to winterize the tankless water heater. I've seen some videos bypassing, using air, using rv antifreeze so I'm wondering what the forums opinions and metods you all use. I don't have an air compressor to use air to blow water out of water heater so is there a method to use that doesn't require a compressor? Thank you.

The problem is the mixing ball on the Furrion Tankless. Its a stainless steel sphere about the size of a softball that has a threaded connection on the bottom that is connected to a stand pipe that extends up into the ball to about .25 inch from the top and it then has a side connector for the hot water out. The standpipe going up the inside does not allow you to get all the water out of the sphere by either draining or using air and you can verify that you have gotten sufficient antifreeze into it. Short story:
I winterized with both compressed air and anti freeze and the sphere ended up freezing and damaging the sphere anyway so it leaked so BAD on our first spring trip that we had to cut the trip short. They don't make replacement spheres. There was a guy who did a bypass of the sphere and we tried that but it actually caused the water temp in the shower to fluctuate. I was talking to my son about it and he said to send it to him and he had a friend who had an FAA aircraft welding certificate and he repaired the sphere and added a drain point so I can drain the sphere completely and can verify that there is anti freeze in it when I winterize. I actually followed the Grand Design procedure for winterizing and they were going to send me a replacement water heater. So far the fix is working well. We winterize for storage in about two weeks so that will be the test. I have lots pics of this whole sordid affair if anyone is interested.

Totally agree. I thought it was super easy actually.....there are plenty of posts with pics and instru

 

[COGrandDes]

The problem is the mixing ball on the Furrion Tankless. Its a stainless steel sphere about the size of a softball that has a threaded connection on the bottom that is connected to a stand pipe that extends up into the ball to about .25 inch from the top and it then has a side connector for the hot water out. The standpipe going up the inside does not allow you to get all the water out of the sphere by either draining or using air and you can verify that you have gotten sufficient antifreeze into it. Short story:
I winterized with both compressed air and anti freeze and the sphere ended up freezing and damaging the sphere anyway so it leaked so BAD on our first spring trip that we had to cut the trip short. They don't make replacement spheres. There was a guy who did a bypass of the sphere and we tried that but it actually caused the water temp in the shower to fluctuate. I was talking to my son about it and he said to send it to him and he had a friend who had an FAA aircraft welding certificate and he repaired the sphere and added a drain point so I can drain the sphere completely and can verify that there is anti freeze in it when I winterize. I actually followed the Grand Design procedure for winterizing and they were going to send me a replacement water heater. So far the fix is working well. We winterize for storage in about two weeks so that will be the test. I have lots pics of this whole sordid affair if anyone is interested.

Question for you.....when you followed the GD procedure for the TWH.....did you take the drain plug and filter plugs out, turn on the pump and ensure antifreeze flowed out both ports? Just trying to see what the difference was.