Anti-freeze ratio

[chast]

Hey All—traveling to the great frozen Northeast in our B-van and expect temps in the 20’s at night. Would like to continue to use the fresh water system and want to add RV antifreeze to the tank. What do you think a safe ratio would be to prevent freezing the outside tank and lines? The tank is 35 gallons.

[time2roll]

chast wrote:
We NEVER drink the water from the tanks and the water would only be used for dishes, showers and toilet.

Seems fine to me.
Chart shows about 1:5 AF to water should work.

[Dutch_12078]

wa8yxm wrote:
One thing.. Though unlike Automotive Antifreeze RV antifreeze is NOT TOXIC. it is still nasty stuff. both taste and the effect it will have on you in quanity. (it is a lower level of poison) So I'd never add it to water I plan on drinking.

The propylene glycol used in RV antifreeze is non-toxic and rated as GRAS, “Generally Recognized As Safe”, by the FDA. It is tasteless and practically odorless.

Propylene glycol is a synthetic liquid substance that absorbs water. Propylene glycol is also used to make polyester compounds, and as a base for de-icing solutions. Propylene glycol is used by the chemical, food, and pharmaceutical industries as an antifreeze when leakage might lead to contact with food. The Food and Drug Administration (FDA) has classified propylene glycol as an additive that is “generally recognized as safe” for use in food. It is used to absorb extra water and maintain moisture in certain medicines, cosmetics, or food products. It is a solvent for food
colors and flavors, and in the paint and plastics industries. Propylene glycol is also used to create artificial smoke or fog used in fire-fighting training and in theatrical productions. Other names for propylene glycol are 1,2-dihydroxypropane, 1,2-propanediol, methyl glycol, and trimethyl glycol. Propylene glycol is clear, colorless, slightly syrupy liquid at room temperature. It may exist in air in the vapor form, although propylene glycol must be heated or briskly shaken to produce a vapor. Propylene glycol is practically odorless and tasteless.

Propylene Glycol - CDC Public Health Statement

[wa8yxm]

One thing.. Though unlike Automotive Antifreeze RV antifreeze is NOT TOXIC. it is still nasty stuff. both taste and the effect it will have on you in quanity. (it is a lower level of poison) So I'd never add it to water I plan on drinking.

But then after the fun I had getting rid of it all the first time I used it.. I never used it again.

When traveling in sub-zero I carried water INSIDE the heated RV and did not fill the fresh system till I was sure it was safe.. I'm "Warranted" for 20 degrees.

[Bobbo]

SoundGuy wrote:

Bobbo wrote:
It should be 100% water, or 100% antifreeze, or empty. Your choice.

Disagree - there's never any reason to introduce RV antifreeze into any fresh water holding tank, ever. When not in use during the cold weather months it should simply be drained of any residual water and left like that, as should the water heater tank, any water remaining will have plenty of room to expand as it freezes and not cause any issues at all.

I agree that there is no reason to put antifreeze in the fresh water tank. However, I stand by my assertion that an RV's water supply should be 100% water, or 100% antifreeze, or empty. Your choice. If you think there is a useful purpose in partially diluted antifreeze, I am willing to listen.

[drsteve]

Automotive antifreeze is ethylene glycol. Propylene glycol has very low toxicity.

[time2roll]

Down in the 20s overnight? Just use the RV as normal with water.

Fill the tank half or more for the night and remove your water connection hose. The fully exposed connection may freeze if left out.

If you must put anti-freeze in the main holding tank search for a freeze chart to give the correct concentration for the exact product you buy.



Example: (propylene-glycol)

[ScottG]

Dutch_12078 wrote:

ScottG wrote:
You should not consume RV AF in any strength. So you cannot dilute and use it to wash dishes, brush your teeth, bath, etc.
You could use it to flush the toilet but once you dilute it, it has no ability to keep water from freezing. It is not like automotive AF.

While I wouldn't recommend gulping down large amounts of it, the propylene glycol commonly used in RV anti-freeze is rated as GRAS (Generally Recognized As Safe) for use in food products by the US FDA. Along with many food products, it's also used in many medications and cosmetics.

Propylene Glycol in Food: Is This Additive Safe?

The tiny concentrations found in food products is NOTHING compared to drinking antifreeze made out of it.

This is one of the big reasons I rarely post here. No matter what, someone always has to come back with an argument. Even in a situation like this where we're discussing something as obviously bad as consuming antifreeze.

[Dutch_12078]

ScottG wrote:
You should not consume RV AF in any strength. So you cannot dilute and use it to wash dishes, brush your teeth, bath, etc.
You could use it to flush the toilet but once you dilute it, it has no ability to keep water from freezing. It is not like automotive AF.

While I wouldn't recommend gulping down large amounts of it, the propylene glycol commonly used in RV anti-freeze is rated as GRAS (Generally Recognized As Safe) for use in food products by the US FDA. Along with many food products, it's also used in many medications and cosmetics.

Propylene Glycol in Food: Is This Additive Safe?

[ScottG]

You should not consume RV AF in any strength. So you cannot dilute and use it to wash dishes, brush your teeth, bath, etc.
You could use it to flush the toilet but once you dilute it, it has no ability to keep water from freezing. It is not like automotive AF.

[maillemaker]

In my rig, the freshwater tank is under one of the beds. The furnace ductwork runs under that bed and out a vent there. There is no direct venting into that space under the bed, but I would bet the residual heat from the duct work at least keeps the area above freezing. Not to mention that the entire compartment is basically inside the living quarters of the RV (though it is under a mattress and some wood). I don't think our fresh water tank would ever get cold enough to freeze as long as the inside of the RV was kept warm enough for people.

Where is your fresh water tank located?

Steve

[2oldman]

Use your heat, not AF. Terrible idea to put it in the FW tank.

dougrainer wrote:
I have never heard of this or been asked the question in 40 years as a Tech.

And he's been on here 14 years.

[garym114]

The only time you use RV antifreeze is when you winterize for winter storage.
To continue to use the RV during the winter, heat and insulation is used

[SoundGuy]

Bobbo wrote:
It should be 100% water, or 100% antifreeze, or empty. Your choice.

Disagree - there's never any reason to introduce RV antifreeze into any fresh water holding tank, ever. When not in use during the cold weather months it should simply be drained of any residual water and left like that, as should the water heater tank, any water remaining will have plenty of room to expand as it freezes and not cause any issues at all.

[MDKMDK]

chast wrote:
Hey All—traveling to the great frozen Northeast in our B-van and expect temps in the 20’s at night. Would like to continue to use the fresh water system and want to add RV antifreeze to the tank. What do you think a safe ratio would be to prevent freezing the outside tank and lines? The tank is 35 gallons.

What year/make/model of B van is it, if I may ask? Some B vans are better suited for withstanding cold temps. What does your owner's manual say about camping in freezing temps?

Anecdotally,
Our 2002 Roadtrek was pretty good at handling freezing temps for short periods overnight. The plumbing was Pex, lines and joints, which had a little room for expansion if the water started to freeze/expand. We usually just tried to keep the inside of the van heated overnight as best we could, opened cupboards to allow some warmer air to reach the plumbing where possible, ran the W/H to keep the tank from freezing, and put some RV A/F in the black/gray tanks via the usual access points (toilet, galley sink). In 9 years of occasional sub freezing temps, we never had a problem.
If the overnight temps start regularly getting below the low 20s Farenheit, with the daytime temps close to freeze, you might want to consider doing a quick blow out winterize of the fresh water system. If your fresh tank is external to the coach interior, I would drain it. Then use bottled water for your fresh water needs.
Good luck with it.