Air/Anti-freeze why we need both....

[Atsushi]

Hello,

I was thinking of upcoming winterizing (I've never done it before). I've read somewhere that some people just use compressed air to blow out the lines and don't use anti-freeze.

I didn't think much of it then, but looking at the plumbing line diagram (We have 2016FC23D), I realize there are only some sections of pipes you can remove water from by air.

https://www.airstream.com/wp-content...Parts-Book.pdf

(Page 477 shows what we got)

Also I used to wonder why do we need air if we are putting anti-freeze. But if there are back-flow protection is preventing fluid going backward, there are some sections of pipes that anti-free cannot get to.

So I've come to understand that we need both air and anti-freeze. Am I right?

Air will blow out the city water inlet line where water from the water pump does not get to, so I don't think there is benefit in putting air and open up all the faucets in the trailer. I think all you need to do is to open one faucet so that the air has place to go (otherwise, wouldn't compressed air burst the pipe?) because the rest of the lines are taken care by anti-freeze.

I'm reasonably sure that I'm correct, but I would be interested in hearing from people who have more experience with this matter.

Thanks!

Atsushi

[KJRitchie]

Since owning my Airstream I've always blown out the pipes using a quick connect fitting screw into the city water, but I have a small compressor. I just use about 30-40lbs of pressure. My water pump is in a spot where it would be difficult to install a antifreeze kit to pump in antifreeze so I always use air. So far so good even down to 5F since 2013. I use antifreeze in the P traps and waste holding tanks after they have be drained and flushed out. I've read some people can taste the antifreeze remnants after de-winterizing but I don't have any personal experience.

Kelvin

[Protagonist]

I have never used antifreeze in the freshwater system, only in the black and gray tanks and my Airstream's macerator pump. Air alone won't remove every drop of water from the freshwater system, but it doesn't need to. As long as the small remaining quantity of water cannot expand to a size larger than the pipe or tank it's in when it freezes, nothing will burst, and that's good enough.

[bwoodtx]

When using air and attaching the hose at the street inlet, start with the faucet farthest from the inlet. Open each faucet in turn-hot and cold and flush the toilet and operate the shower. You can also drain the hot water tank. When all done with this, open the low point drains and leave open. You will get about 99% of the water doing this.

Antifreeze in the P traps and B & G tanks and you're good.

[Protagonist]

Originally Posted by bwoodtx

Open each faucet in turn-hot and cold and flush the toilet and operate the shower.

Antifreeze in the P traps and B & G tanks and you're good.

If you have an external shower, don't forget to hook it up and clear the water from the shower fixture on the side of the Airstream.

[Wayne&Sam]

2x what bwoodtx and protagonist said. I’d add to disconnect the output line from the water pump, put a towel under it and get that bit of water too.

[jdalrymple]

I have always simply blown out the plumbing.


Drain the fresh water tank and let the pump run dry a few minutes.

I do open the low points to let whatever water will drain out there. I then close them, bypass the water heater and attach the air line to the city water hookup.

I set the compressor regulator at 65 psi and let each faucet, commode, shower, and filtered water dispenser run until it blows only mist.

As mentioned don't forget the outdoor shower AND the black tank flush connection.

This flush connection is plumbed through a check valve that does hold enough water to freeze and break.


Drain the water heater via the external drain plug.


Add antifreeze to the traps and I have always been good.





Regards,

JD

[WayneG]

Air will not help with your fresh water tank or your water heater. There are low spots that will never drain.
I do both. Blow out the system with air, then I use about 5 to 6 gallons of antifreeze to be sure the water tank, pump and hot water heater are safe. At $3 a gallon, it is cheaper than repairs.
Then I blow out the excess anti freeze and wait for spring.
PS: if you have a cartridge water filter, dont forget to pull it before antifreeze.

[uncle_bob]

[QUOTE=Atsushi;2016326]Hello,

.... I think all you need to do is to open one faucet so that the air has place to go (otherwise, wouldn't compressed air burst the pipe?) ....../QUOTE]

Hi

The pipes must withstand at least 60 PSI simply to operate with city water. Since they are actually residential plumbing, they likely are good to 120 PSI. I would not bet on the higher number, but it is a pretty good guess.

Simple answer here is to set the regulator on the compressor to something below 60 PSI.

Bob

[Protagonist]

Originally Posted by WayneG

Air will not help with your fresh water tank or your water heater. There are low spots that will never drain.

This is true. But water only expands by about 9% in every direction when it freezes.

A small amount of ice in the plumbing system does no harm, as long as that 9% expansion rate doesn't cause anything to bulge. A pint or two of water in a 6-gallon water heater or a 26-gallon (in my Airstream) fresh tank will do no harm even if it freezes.

There are a few places in the system where even a small amount of water could do harm, because of the presence of small moving parts. Inside a faucet, or a drain valve, or a check valve, or inside a pump. As long as compressed air clears those, a small amount of water elsewhere in the system really doesn't do any harm.

[Adventure.AS]

Originally Posted by Atsushi

...
Also I used to wonder why do we need air if we are putting anti-freeze. ...
So I've come to understand that we need both air and anti-freeze. ...because the rest of the lines are taken care by anti-freeze.

Atsushi

I prefer not to use the RV antifreeze in the fresh water lines as compressed air works well and I don't like the chore of flushing out the system in the spring.

However, I understand why some people would feel more secure also using the antifreeze. If you do, then consider the final step to blow out the lines with compressed air. This will take out most of the antifreeze so that you won't have the residual taste when you de-winterize next spring. If you capture the expelled antifreeze you can also use it to put into the p-traps and the black and grey water tanks.

[Rich W]

We can get pretty cold sometimes. Negative temps are not unusual. I like a belt and suspenders. air and antifreeze.

I blow out the lines, including the kitchen sprayer and water lines to the water heater (before putting into bypass mode).

I rarely use the fresh water tank, although I sanitize in the spring. I leave it empty in the summer and just carry a few gallons of water for flushing and drinking if we go south for the winter. I have the connector for the pump to push antifreeze into the lines. This takes care of the pump line to the rest of the AS. The drained fresh water tank input to the pump will be empty by the time winter arrives.

In the spring, I flush the lines through the water pump using fresh water from the tank, after sanitizing it. If you don't, the residual antifreeze between the pump and first tap will be with you for a while. Don't forget the showers, inside and out. Last thing I do is to switch the bypass and fill the water heater (empty, repeat).

When all of the lines are flushed there shouldn't be any foaming or bad taste. Our results have been good, but I still buy bottled water for the coffee pot.

[robert claus]

I just blow mine out - don't like anti-freeze, which is not something I would choose to drink, in my water lines. Don't forget to disconnect the the water pump so it can drain out, and blow out the sink sprayer.

[Atsushi]

Before you put compressed air in the city water intake, do you close low-point drains?

I think they need to be closed otherwise the air will escape from them, right? The idea is to let the air rush out from the faucets/shower/toilet, etc.? Yes?

Atsushi

[Minno]

Don't forget to leave antifreeze in your toilet bowl. Otherwise you will have a dried out seal that won't do it's job come spring. We fill the bowl about half way up with antifreeze, then cover it with plastic cling wrap so it won't evaporate over the winter.
We both blow and use antifreeze in our system. We tried the blow only once, and had to replace our water pump in the spring. Might be because we WILL be at -20F at some point over the winter (or colder). We flush the water system enough in the spring with sanitizing to not have a flavor from the antifreeze.

Kay

[Adventure.AS]

Originally Posted by Atsushi

Before you put compressed air in the city water intake, do you close low-point drains?

I think they need to be closed otherwise the air will escape from them, right? The idea is to let the air rush out from the faucets/shower/toilet, etc.? Yes?

Atsushi

Here is a new video from James @TheFitRV where he uses a bicycle pump to demonstrate that even it could be used to winterize. And, yes he does leave the tap closed until the system is pressurized.

https://www.youtube.com/watch?v=Rf-DJCDPMkk&t=8s

[uncle_bob]

Hi

Ok, if we are into cute tricks:

Open all the low point drain valves and open all the faucets. Also hit the toilet flush lever. You want air in all the lines if you can get it. Now, with everything "open" go out for a drive with the trailer. Nice bumpy roads in the hills are best. We don't seem to have any other kind around here . It does not have to be a long drive. The idea is to shake the lines up and "slosh" as much water out as you can. Some open everything up for the last drive home of the year.

When you grab the big compressor to blow out the lines, you pull the oiler off of it. Don't forget about the *hose* that you hooked up with the oiler and the air tools. It's pretty well coated with oil inside it. I keep a second "no oil" hose around for this reason.

If your compressor has a tank, find the water dump valve on it. Dump the tank. Yes that's yucky stuff coming out. You don't want to blow it into your water system.

With compressors, bigger is better. More flow will get the job done quicker. For pesky places in the plumbing, more flow might get water out better. If that's not clear, think about a long vertical pipe with air just bubbling through the water .....

PEX is great stuff. It's saved me several times. The pipe it's self is pretty indestructible freeze wise. I have data on this. What is not as happy freeze wise are the metal crimp bands that fasten the pipe to the connectors. They are just plain old metal. Freeze right at that point and you will stretch the metal band. Likely result will be a leak. Yes ... I have data.

If you *are* going the "air only" route. Take your time. Air is cheap. Bring a good book. Don't just go for "no more water". Let it run for some number of minutes after you think it's done.

It's tempting to leave the drains open after the "all air" process is done..... errr ..... bugs .... bugs looking for a warm home in the winter ..... stink bugs looking for a warm home in the winter ...

I've always wondered if they make RV anti-freeze in different flavors ... maybe cherry this year ....

Bob

[rmkrum]

Originally Posted by Atsushi

Before you put compressed air in the city water intake, do you close low-point drains?

I think they need to be closed otherwise the air will escape from them, right? The idea is to let the air rush out from the faucets/shower/toilet, etc.? Yes?

Atsushi

Yes. The low point drains need to be closed while flushing the faucets, shower, and toilet valves (plus toilet rinse gadget hose if you have one).

The low point drains should be opened LAST so they can be cleared of water with the air flowing through the system...

[m.hony]

Originally Posted by jdalrymple

I have always simply blown out the plumbing.


Drain the fresh water tank and let the pump run dry a few minutes.

I do open the low points to let whatever water will drain out there. I then close them, bypass the water heater and attach the air line to the city water hookup.

I set the compressor regulator at 65 psi and let each faucet, commode, shower, and filtered water dispenser run until it blows only mist.

As mentioned don't forget the outdoor shower AND the black tank flush connection.

This flush connection is plumbed through a check valve that does hold enough water to freeze and break.


Drain the water heater via the external drain plug.


Add antifreeze to the traps and I have always been good.





Regards,

JD

I have had the check valve on the black tank flush system to freeze and break...

[MelGoddard]

Originally Posted by KJRitchie

Since owning my Airstream I've always blown out the pipes using a quick connect fitting screw into the city water, but I have a small compressor. I just use about 30-40lbs of pressure. My water pump is in a spot where it would be difficult to install a antifreeze kit to pump in antifreeze so I always use air. So far so good even down to 5F since 2013. I use antifreeze in the P traps and waste holding tanks after they have be drained and flushed out. I've read some people can taste the antifreeze remnants after de-winterizing but I don't have any personal experience.

Kelvin

Same here😆
I use about 45-50 psi.& AF in P traps.