blowing out water lines for winterizing

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.

therealsimpsons

Well-known member
Joined
Aug 23, 2009
Posts
1,405
Location
1 mile south of the Cheddar Curtain
Hello all,

I've done lots of research on here and the internet regarding winterizing. Our plan is to do it ourselves this year. I read the comment "blow out the water lines".  With a portable air compressor? What size is necessary? If we're going to go buy one, should we buy one big enough to inflate the tires on the RV while we're at it?

I'd appreciate comments. Thanks.

Stan and Becky
 
You don't need a large air compressor, but you need one that runs on 120VAC and has an air tank on it.


My compressor is 2HP, 6 gallon tank and has 3.8CFM@40PSI and 2.0CFM@90PSI.  It' more than adequate for that.


If you don't have a compressor though and don't need one other than winterizing, the payback will be a few decades.  If you have other uses for it, then it's different.


Before buying a compressor, make sure to identify all the things you plan to use it for and buy one that can handle the most demanding job.  For example, mine is too small for my needs.  I often use an impact wrench with requires 4CFM@90PSI which mine cannot deliver.  I still use it, but when the compressor kicks in, I have to wait until the tank is recharged before I can use it again.  I use that time to take a few sips of beer.


A more powerful compressor will deliver more CFM at any given pressure and quicker recovery.
A less powerful compressor will deliver less CFM at any given pressure and also will be much longer to recover.
The size of the tank affect recovery time and frequency.
 
Stan & Becky:

It's good to have a Tire pressure pump as one travels.... I have had this pump for a few years and used it often. IT WORKS WHEN BLOWING OUT WATER LINES DURING "WINTERIZING". BUT, I would still add Antifreeze.

http://www.sears.com/shc/s/p_10153_12605_02875117000P?prdNo=3&blockNo=3&blockType=G3


 
you must also check the output pressure. the Sears model is capable of 120 psi. your water lines will get really big really fast. (as in explode) I would use no more then 30psi to clear lines.
 
1275gtsport said:
you must also check the output pressure. the Sears model is capable of 120 psi. your water lines will get really big really fast. (as in explode) I would use no more then 30psi to clear lines.

Agreed.  That's one advantage of a model with an air tank as they normally have pressure regulator as the proper pressure can be dialed in.

Note that a pressure regulator can be added to most compressors/inflators, but usually costs more to add after than get one already built-in.
 
I run 120 psi of air through my lines with the faucets open...this will clear out the water and obviously doesn't cause damage. Running 30 psi won't get all the water out. 
 
We use a 2HP 6 Gal. compressor for winterizing, adding air to tires, rotating tires with a impact wrench, blowing out dirt and dust from many things, etc. Well worth the investment. As for winterizing this how I do it.

1. Drain fresh water tank, close valve.
2. Drain hot water heater replace drain plug.
3. Dump and (flush if possible) both black and gray water holding tanks, leave gray water valve open.
4. Screw compressed air adaptor into the fresh water inlet. The adapter is available from Camping World or most RV dealers.
5. Apply compressed air, keeping the pressure at 30 PSI but less than 40 PSI. You may need someone to hold the air hose on the adapter.
6. Open then close each faucet, hot and cold, one valve at a time, allowing the compressed air to force the water out of the line. Don't forget the shower and toilet and outside shower. Open both low point drains and close.
7. Remove the drain plug from the hot water tank and allow the compressed air to blow out the remaining water. Reinstall drain plug.
8. Remove the compressed air source and adapter. Close gray tank valve.
9. Pour a few cups of RV antifreeze down each drain and toilet.
10. You?re done
 
RVIA standards call for testing RV plumbing at 100psi and that's with non-compressible water.  Air pressure of more than 30psi won't bother the plumbing.
 
Marc L said:
Agreed.  That's one advantage of a model with an air tank as they normally have pressure regulator as the proper pressure can be dialed in.

Note that a pressure regulator can be added to most compressors/inflators, but usually costs more to add after than get one already built-in.

I bought a regulator at Lowes for $18. I added fittings I already had so I can plug it in or not, depending on need. I used it to blow out the lines at 30psi as the Winnebago manual says is the max pressure. http://www.winnebagoind.com/resources/service/pdfs/2004-12%20Winterizing.pdf
Made a fitting to attach the air line to the hose connection and let it run untill there was no more gurgling. Made it an easy one-person job--although I will probably figure out a device to hold down the toilet lever instead of my foot. BORING!

I'm not willing to test the pressure rating on my plumbing yet.
 
On the other hand, the procedures I have seen for blowing out air lines say to use about 25-30 psi.  Air volume through the lines is much more important than the pressure and most low-mid priced compressors produce a relatively small volume of air at higher pressure. Better off keeping pressure low and volume high. Even 60 psi is a lot - you probably don't even run the water pressure that high (the standard RV water pump or regulator is 45 psi).
 
I agree with lostagain, I took mine to a RV service man that has been using the same steps that lostagain posted for over 15 yrs and has never had a problem.  He guarantee?s his work and if there is no water in the pipes there is nothing that will freeze.  The idea is to blow all the water out of the lines which then there is no need to add antifreeze to the pipes only the traps.  Also makes it easier to de-winterize. 
 
There are some variables too.

If one is to open ALL the faucets including the low point drains and only connect an air compressor set at 120PSI, if the compressor has a low volume of air, the pressure won't stay at 120PSI for long and cannot do much dammage.

On the other hand, I do the opposite, I connect the air first, then open each faucet one by one, so the air pressure does build-up in the system from one faucet to the next, that's why I set my pressure at 40PSI.

I won't get into details of air pressure VS air volume because I am not qualified, but I do know it's more complex than just setting a knob.
 
If the pix associated with your post is your RV, then a portable one or two-gallon air compressor will not inflate those tires. It will do a decent job of blowing out air in your lines, tho.

Having said that, I have often wondered why one thinks there is a need to even blow out lines. With the exception of the P traps and a whole house water filter canister, evaporation will happened in a short time if all of the drain valves and faucets are opened. The holding tanks may contain some residual water even after dumping or in the evaporation process, but there must be enough moisture to freeze and press against confined surfaces. It isn?t going to happen.

My ?winterizing? technique for a decade and a half is to open all valves for evaporation, disconnect and drain sink P-traps, remove the in house water filter, and pour some vodka in the shower P-trap (the rest I drink). I?ve never had an issue with frozen lines.

It works for me, but if someone can provide a solution that works better that this 30 minute routine, then I am open minded enough to listen.
 
One of the hundred dollar pancake compressors from places like Sears, Lowes, Home Depot is more than enough to blow out the water lines.  What you need is volume not pressure.  20 PSI is sufficient.  One of these would also allow you to check/inflate your tires at home too.  Just don't expect them to blow up a flat tire in two minutes, but are probably well worth the cost for the average home owner/RVer.
 
One thing to look out for is a in-line filter and make sure it is removed.  If it is full of water it will crack the filter casing when it freezes.  On my old camper the filter was next to the pump.  I'm in upstate NY and it gets really cold up here, so I blow out all the line, run antifreeze into the pump, drain all tanks, leave all vales open and put antifreeze in the drains.  I pull the drain on the water heater and leave it out.  I did it yesterday and it took 30 minutes total.

The last thing I did was write a note to myself so next spring I don't forget the way I left the system. 

Easy to do, no problems next year.
 
MikeyInNY said:
The last thing I did was write a note to myself so next spring I don't forget the way I left the system. 

Easy to do, no problems next year.

I like the note idea, but I never get that far.

I also disconnect the shower hose, it tends to hold a little water and split one year.

That reminds me, forgot the outside shower. I guess I know what I'm doing tonight.
 
MikeyInNY said:
One thing to look out for is a in-line filter and make sure it is removed.  If it is full of water it will crack the filter casing when it freezes.  On my old camper the filter was next to the pump.  I'm in upstate NY and it gets really cold up here, so I blow out all the line, run antifreeze into the pump, drain all tanks, leave all vales open and put antifreeze in the drains.  I pull the drain on the water heater and leave it out.  I did it yesterday and it took 30 minutes total.

The last thing I did was write a note to myself so next spring I don't forget the way I left the system. 

Easy to do, no problems next year.

I use a whole house filter with an activated charcoal cartridge.  It had only a couple hundred gallons of water through it at most by the time I needed to winterize.  I emptied it for winter and tried to reuse the next spring.  After much troublesome troubleshooting I found that hardly any water would pass through the filter.  Don't know how drying out would clog it but it did.
 
Lostagain,

Thanks for your list.  I sorta knew all the steps but mostly relied on memory. I took the "liberty" of copying your list and pasting to Excell and have printed a checkoff list for myself to use when winterizing . I did add one step, as suggested by Mikeyin Ny and added disconnecting (removing the water filter (under the sink in my coach). It brings to mind, for me, the time I winterized and forgot to open the toilet flush valve to purge the water from it. :eek:. I had to replace the toilet in the spring. :-[





 
I just put a two way valve winterizing "kit" on my RV. It goes in between the tank and pump, in one position it allows water to be drawn from the tank. In the other position it draws antifreeze in through a hose. I just went from tap to tap and the toilet and shower until each of them ran pink for a few seconds.

This is my first experience winterizing an RV, so now I'm a little worried that I didn't do this correctly. Does it sound like I'm going to be okay with the technique I used???  Thanks, Tim
 
I have been thinking about "lostagain's" winterizing and have a question about dumping the black and gray water tanks. Why do you leave the gray water valve open? Do you leave the valve open and put the cap on the opening or do you leave the pipe end open and put a catch pan under the open pipe? :-\
 
Back
Top Bottom