Sunday, May 28, 2023


How do I keep my RV’s on-demand water heater from freezing?

Dear Dave,
Grand Design installed a Furrion 2.4 gpm tankless water heater in the Reflection. I did some research on this heater, and the heater manual recommends not using it below 39 degrees F. Well, that is almost impossible in Oregon. My dealer was not aware of this. Bottomline is the heater froze and looks like it’s toast, per mobile repair tech. Question is, do you know if Furrion has done anything to address this issue? I’m probably due a new heater, and dealer has recommended apples to apples for replacement. Thanks. —Steve L., 2021 Reflection 303RLS

Dear Steve,
Since the water heater has an exterior vent and water in the system, it has the potential to freeze at temperatures below 32 degrees. That has been the issue with on-demand systems as they sit dormant until a faucet is opened and the call for water pressure.

Furrion has a new module board called Control Unit With Freeze Detector that is designed as an antifreeze option that is $103. Part Number 2022006595. It turns the unit on automatically if the temperature goes below 38 degrees and heats the water to keep it from freezing. It will then shut off at 58 degrees.

Furrion Anti-freeze protection

According to the Furrion website, the new models have the Anti-freeze Protection: Vortex + Anti-freeze Protection.

According to Furrion, unlike traditional limited-capacity tank systems, your hot water supply will not run out. The Vortex technology prevents cold spots by mixing the water prior to delivery, preventing inconsistent water temperatures. With the new antifreeze protection feature, the RV tankless water heaters will deliver hot water during any camping season.

It does seem like a waste of propane to constantly cycle on and off during below-freezing temperatures. I did see several posts in forums that owners bought a shop light with a 40-watt bulb and placed it in the compartment. We did that in pop machines back in the early days and it worked well. Not sure if I would want to “test” that with a new unit.

Truma on-demand water heater

Another option is the Truma model that has a 12-volt heater that turns on when the water gets close to freezing. That seems to be a better option than running the propane as often. I guess it all depends on if you are boondocking and what you have for 12-volt amp-hour capacity.

We did a video review at the Tampa SuperShow on the unit for RV Lifestyle and Repair Club. The unit has a quick-drain feature for winterizing that was very impressive. Just pull down the handle and it drains all the water so you could manually winterize it if you know you will not be needing hot water for awhile. Otherwise, you could install a bypass valve and pull the drain plug on the other models.

 You might also enjoy this from Dave 

Can I install a single on-demand water heater for RV’s kitchen and bathroom?

Dear Dave, 
I purchased this trailer in November 2021 from Lazydays outside of Memphis. It was known I was taking the trailer to my home in Maine. The trailer was parked all winter in Maine. In the spring I took it to my lot in Northern Maine. Well, all the water lines were damaged, and the water heater didn’t work. Lazydays apparently hadn’t winterized the trailer, and I never asked them if they did. My question is, can I install a single on-demand water heater that would take care of the kitchen and bathroom? Usually, it is just me at the trailer, so I don’t use a lot of hot water. Your sage advice will be appreciated. if my solution isn’t feasible, any advice? —Bill, 2018 38-ft. Keystone Cougar fifth wheel MKS37

Read Dave’s answer.

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

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Dave Solberg
Dave Solberg
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. He has been in the RV Industry since 1983 and conducts over 15 seminars at RV shows throughout the country.


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1 month ago

at the cost of a new unit I would sleep better at night if I had some sort of indicator that the freeze protection is working and or an alarm to alert me to a freezing situation. This is an easy circuit to make and should be easy to wire in.

Thomas D
1 month ago

If it’s near freezing I’d winterize the whole rv, not just the heater. I’ve got exposed pipes in my basement and know it gets below freezing in there

Ed Fairchild
1 month ago

I dont own one and probably wont but I dont like the idea of needing power and lp constantly while stored. Why not install a bypass valve on both sides of it and fill just the heater with antifreeze.

Jeff Roller
1 month ago

I bought the replacement board from Furrion that has the freeze protection. I have a 2022 GD 303RLS and don’t believe they started shipping the unit with freeze protection until 2023. The board was around $120 delivered and a direct replacement for the original, even kept the original wiring loom.

To keep from freezing both the external and internal power must be turned on.

1 month ago

On Oasis and Aqua Hot systems the distribution module is separate from the boiler and is installed tucked inside a heated bay. That design eliminates this issue with those systems. The downside is those systems take up more space, but since they are also the heat source for the RV, maybe not since it eliminates the forced air furnace.

With the incoming and outgoing water lines near ambient temp air on a Truma or Furrion on demand heater, wouldn’t there still be a freeze potential since only the water in the unit’s coils would be kept warm?

Mike Johnson
1 month ago

Dave, I have the Furrion tankless water heater. How can I tell if it has the anti-freeze module?

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