Winterizing with Compressed Air

[BinaryBob]

For years I've used anti-freeze. With the new rig, I'd rather blow the lines out.
I know it's the wrong time of the year, but I thought it would be a good time to test this (new to me) procedure with the lines now full of the pink stuff.
The manual says to use the compressor with the drain valves open and the water heater drain plug out. This makes no sense as this leaves no air pressure build up in the lines. I also found the recommended 30 psi inadequate. Around 45 did a much better job.

For my test, in blowing the pink stuff out of the lines I could still see anti-freeze in some of the lines and water angle fittings. Just how dry does this procedure need? I opened each faucet one at a time, rotating through them all three times. Even the third time I had water spitting. Is this acceptable?

The manual also says to close all valves and faucets when finished. Wouldn't it be better to leave them all open to allow water expansion in the lines during the winter?

I didn't find anything in the library for this method of winterization.
Could some of you experienced "line-blowers" share your detailed method of how you winterize?
I don't want to miss any detail that could turn into an expensive mistake. (ex. might be a good idea to remove the strainer bowl from the water pump?)
Thanks!

 

[John From Detroit]

I set the regulator on the compressor to 50 PSI (Same as I do my water reguators)

Opened every valve. bypassed and drained the water heater (no need to blow it out it has a nice gravity drain) Blew till my 6 Gallon compressor ran out of air. While it was re-pressurising I cycled the ice maker manually (Turn teh big wheel in the direction indicated) then closed the valve feeding it after it had cycled (Gravity will drain that line)  Blow blow blow blow (like 5-10 cycles.. Close everything and pack up.  Last blows there was no gurgling. no water nothing but air.

 

[Gary RV_Wizard]

You don't need high air pressure to blow lines out - you want a high volume of air.  Most small compressors lose volume as the psi is increased, so 30 or so psi is more effective. 

I'd like to see those instructions you used, cause I feel they are faulty.  I would not open all the faucets and drains at once because you lose too much air.  With the low point drains open, there shouldn't be much liquid in the lines anyway.  Close the low point drains once they stop running liquid and then turn on the air to get the rest.  Open one faucet at a time to vacate that section of line.  The tank should be bypassed and drained (if it wasn't already (per John's reply).


Follow-up: Well, I found some other winterizing instructions that match what BinaryBob used. Seems all wrong to me.
https://www.reserveamerica.com/outdoors/how-to-winterize-an-rv.htm


This article is the procedure I've used [successfully] in the past.
http://www.kinstler.com/how_to/winterize_an_rv/how_to_winterize_rv.html

 

[Rene T]

On my last trip, on the way home I would open all the faucets and the low point drains. Most of the water would find it's way to the drains. Then when I got home, I'd shut all the faucets and drains, let the compressor build up pressure,and set my pressure to be around 40 PSI. Then I'd hook up the air hose to the water inlet with a quick disconnect. Then I'd go inside and open every faucet one at a time until only a slight mist would come out. Then I'd let the compressor build up pressure again then go to the next faucet. I'd do this 2 or 3 times. Then I'd close every thing so no bugs would get in there. Don't forget the toilet. Also run the water pump for a few seconds so you get all the water out of it. I forgot to say to bypass the water heater. Open the heater drain and once drained, just screw in the drain plug loosely to keep bugs out. 
There are other ways but this procedure always worked for me.

 

[Drewd]

50 psi is hardly high pressure and I typically use 60 psi in my system to blow out all water from my system.  With a 25 gallon compressor, it takes me 3 tanks to get every bit out. 

Don't forget to add some antifreeze down the drains to displace water from the traps.

 

[Gizmo100]

On my last trip, on the way home I would open all the faucets and the low point drains. Most of the water would find it's way to the drains. Then when I got home, I'd shut all the faucets and drains, let the compressor build up pressure,and set my pressure to be around 40 PSI. Then I'd hook up the air hose to the water inlet with a quick disconnect. Then I'd go inside and open every faucet one at a time until only a slight mist would come out. Then I'd let the compressor build up pressure again then go to the next faucet. I'd do this 2 or 3 times. Then I'd close every thing so no bugs would get in there. Don't forget the toilet. Also run the water pump for a few seconds so you get all the water out of it. I forgot to say to bypass the water heater. Open the heater drain and once drained, just screw in the drain plug loosely to keep bugs out. 
There are other ways but this procedure always worked for me.

This is how I did our winterizing with air except I set the pressure @ 30 Psi. I don't see any harm in the higher pressure but 30 works for me.

 

[John From Detroit]

"Most small compressures loose volume as pressure increases".

Yes they do.. BUT the compressor fills a six gallon tank to 160 PSI as measured (150 promised) this is the same compresser I use for my 22.5" tires and 12 ton jack.

That provides a good long blow before the pressure, and thus the volume, starts to drop

Then I let it re-charge and blow again and again and again.  You missed that it was a 6 Gallon Compnressor. not 6 GPM but 6 Gallons at 150 PSI.

WHy open all valves including Tub/Shower kitchen and outside shower?

Well if you do not open those valves the lines to them (Longest line in the RV in fact in my case feeds the shower) will NOT be blown out. they will remain mostly full of water.

If you wish you can close them but the compressor blew enough air in for them to be dry by the time I was done.

 

[Gary RV_Wizard]

You missed that it was a 6 Gallon Compressor. not 6 GPM but 6 Gallons at 150 PSI.

No, John, I didn't miss that.  It is BinaryBob's compressor that is in question, not yours.

 

[BinaryBob]

Thanks for the responses.
I have a 6 gal. compressor as well.
Sounds like I need to open and close each faucet in rotation more than I did.

 

[scottydl]

On my last trip, on the way home I would open all the faucets and the low point drains. Most of the water would find it's way to the drains. Then when I got home, I'd shut all the faucets and drains, let the compressor build up pressure,and set my pressure to be around 40 PSI. Then I'd hook up the air hose to the water inlet with a quick disconnect. Then I'd go inside and open every faucet one at a time until only a slight mist would come out. Then I'd let the compressor build up pressure again then go to the next faucet. I'd do this 2 or 3 times. Then I'd close every thing so no bugs would get in there. Don't forget the toilet. Also run the water pump for a few seconds so you get all the water out of it. I forgot to say to bypass the water heater. Open the heater drain and once drained, just screw in the drain plug loosely to keep bugs out. 
There are other ways but this procedure always worked for me.

This is almost exactly the process I've followed the last several years, except I didn't think to open the faucets/drains during the last trip to let gravity/inertia take its course and pre-drain the system. Good idea!

 

[Hanr3]

I do things slightly different.
I open every faucet, shower (inside and outside), drain the hot water tank and open the fresh water tank drain and each of the low point drain lines. Roll my 60 gallon vertical compressor out to the camper and adjust it down to 50-60psi. Reinstall the hot water tank anode and hook the compressor up to the fitting.  Enter the camper and drain the toilet (closest line to my fill), then work my way around the camper a closing the cold water faucets as they spit air. then I go back and close the hot water faucets as they spit air.
Then I let the system build pressure with everything closed and the tank refills.
Once the compressor tank is full, I start at one faucet and open both the hot and cold to ensure there is no more water. Walk the loop in the camper, don't forget the outside shower.
Then disconnect the compressor from the camper, put everything away and open the low pressure lines to relieve pressure in the system.

 

[Rene T]

I do things slightly different.
I open every faucet, shower (inside and outside), drain the hot water tank and open the fresh water tank drain and each of the low point drain lines. Roll my 60 gallon vertical compressor out to the camper and adjust it down to 50-60psi. Reinstall the hot water tank anode and hook the compressor up to the fitting.  Enter the camper and drain the toilet (closest line to my fill), then work my way around the camper a closing the cold water faucets as they spit air. then I go back and close the hot water faucets as they spit air.
Then I let the system build pressure with everything closed and the tank refills.
Once the compressor tank is full, I start at one faucet and open both the hot and cold to ensure there is no more water. Walk the loop in the camper, don't forget the outside shower.
Then disconnect the compressor from the camper, put everything away and open the low pressure lines to relieve pressure in the system.

The only problem I see is that you said you reinstalled the tank anode. So as you're blowing down, much of the water will be going into the tank and the air will not be able to blow it out because the outlet is up high. Some have a check valve in the cold line going to the tank. There may be a chance that some water could stay in the tank and if it freezes, it could split the tank. I think you should always just bypass the tank then when all done drain the tank.

 

[WILDEBILL308]

I have seen at least 2 post this season where people who used the compressed air method have had damage from freezing. If you don't get everybit of water out it will run to low points in the line. The new pex tubing is fairly forgiving of freezing but the fittings, not so much. I think it might be ok but would be very cautious to get it dry.
Fortunately I don't have to winterise. ;D
One outher place to drain some don't know about or forget is the foot valve on the toilet. It is out of site/mind. You can just unscrew the bottom of the valve assembly.
Don't forget the washing machine.
Bill

 

[Mark_K5LXP]

My owner manual has a prescribed order of which valves to open.  Doesn't say for how long though.  I have a big enough compressor to keep up so I let each fixture blow long after it has stopped spitting any water.  Probably a good 5 minutes per fixture.  I'm always nervous about just what might have been missed but so far no surprises.  Finished off with a glug of olive oil in the toilet then a few glugs of antifreeze in the drains.

Mark B.
Albuquerque, NM

 

[Hanr3]

The only problem I see is that you said you reinstalled the tank anode. So as you're blowing down, much of the water will be going into the tank and the air will not be able to blow it out because the outlet is up high. Some have a check valve in the cold line going to the tank. There may be a chance that some water could stay in the tank and if it freezes, it could split the tank. I think you should always just bypass the tank then when all done drain the tank.

Ah yes Rene. I forgot to include that remove the anode for the winter. In the spring I install a new anode. Since I just installed a water filter system, I will also be removing the cartridges and leaving them off for the winter too. In the spring install new ones.

 

[Rene T]

Ah yes Rene. I forgot to include that remove the anode for the winter. In the spring I install a new anode. Since I just installed a water filter system, I will also be removing the cartridges and leaving them off for the winter too. In the spring install new ones.

I would screw it in loosly just to keep the critters out of there and if any water does get back in there, it will leak out.
No need to replace it every spring unless it's really eaten away.

 

[KandT]

I used to blow them out until I went through all these problems - Potable stuff is cheap and worth it for me.