Winterizing Air Pressure
 

Good morning. I have read several of the winterizing threads, but still have a question. I am looking at a 100 p.s.i. pancake style air compressor from Harbor Freight. (On sale for $39.00.) Is that enough pressure to properly winterize my coach? We live in Georgia so we don't get the extreme cold for long periods of time.

Thanks in advance for your response.

100 PSI would be too much air pressure on the lines. I am not how much PSI your lines can handle. I use about 40 PSI on mine and it is plenty to blow out the lines. I assume you can regulate the pressure on the pressure on the compressor you are looking at.

Sounds like a good price. You should set your regulator to 25-30 psi when blowing out your lines. Too much pressure is not good. :)

X2 plenty

Thanks for the info
 

Thanks for your response. I was just not sure that compressor would be big enough to handle the job. It looks like it is. I am sure it has a regulator on it to control the pressure.

We will probably be using the rig during the winter months as it does not get down to freezing around here that often. I guess I would be blowing out the lines after each use while the weather is still cold.

The one-star reviews on that compressor are a bit scary. I have this one and it works well:

https://www.lowes.com/pd/CRAFTSMAN-6...sor/1000595167

I have the air comp you are talking about. Just set the regulator at 30 and it should work fine. When you blow the lines you need more volume and not so much pressure. I would only open a few things at one time due to that comp does not have a lot of volume.

I set my regulator at 50psi. Your plumbing lines and fittings can likely handle much more. However the faucets and other devices in the water system can not.

I'm in Georgia too... on the north side of Forsyth county.

I don't do my camper 'till December (last year I think it was Early January). Lower your pressure down a bit and you'll be fine. Don't forget to open the line (faucet) prior to adding air.

IIRC, either the faucet or toilet I removed recently for clogging was marked 60psi use maximum.

you need pressure and volume. that compressor will make pressure you need but not the volume, it will run none stop trying to keep the pressure up. I know not everyone has one but I have a 60 gal air compressor and I keep air flowing through my line for 30 minutes it takes that long to get all the water out but I a 40 ft 5th wheel with a washing machine and a residential frig with 2 ice makers that need to be completely blown out, like others have said keep the pressure 30-40psi

X2. 30 - 40 PSI is sufficient

I found out about toilet "guts" not doing so well with higher pressure. WHen we built our house a street regulator wasn't installed. So we had at least 80LB of pressure before any hot water pressure build up. Replaced the stuff inside the toilets within 6 months. Street regulator and expansion tank later all is good. LOL

Wow. I've never done anything but "puff" air from my compressor, set about 45 psi. DW opens faucets one at a time until the majority of the water is blown out. Takes me about 5 minutes maybe. Haven't had a problem in 35 years of hard sided campers. Have never used the pink stuff except pour a little into p-traps and toilet bowl.

When I say 30 minutes I just let air go through the lines while i do other stuff to the RV, but i do have to run the washer through a wash cycle to get all the water out of the washer and the ice makers have to run a cycle also.

That's what I use, only not at 100 psi.

I have the same compressor. At 40 psi, it does the job just fine. Get it up to pressure and start blowing. Mine will cycle on and off to keep the pressure at 40.

Most people will advise you to use 40 - 45 psi for CG water pressure, so 40 psi should be good when blowing out. I wouldn’t go lower.

Watch out for higher pressure, too. I found out recently (not disastrously, thank goodness) that 65 psi will cause my sink faucet to “pop” spectacularly. This is a weakest link scenario. Even if some of your system can handle 100 psi, not everything can. The weakest link (in my case, the kitchen faucet) WILL blow.

Winterize
 

My pancake has a max @ 135. I air it up and turn the out pressure to 30 PSI. There is enough air to do my 27" trailer w/o plugging into power. Remember to do outside shower and toilet. I am able to do it at the storage lot. After blowing it out, I open low water drains, fresh water drain and empty water filter bowl. Then put a cup of RV anti-freeze in all the drains and toilet.

If one were to look at the orifice size of the usual air fitting used to connect air line to City Water fitting they'll see it's only about 1/4" ID. This restricts the effective pressure in the water system greatly due to the flow restriction.

Don't worry excessively about air pressure as long as air is flowing through an open faucet or drain. Unless you have a large volume shop air compressor chances are it will be impossible to even reach 50 PSI while blowing out lines unless all faucets are shut off and air left connected.

FWIW, RV water systems are tested to 80 PSI.

I think you will find it is the air volume that moves the water out of your lines.
You could put 20, 40, 60 or even 100 psi in a water line but until you open the valve to get air flow you will not move the water out.
Note I think many RV water systems with plastic fittings are only rated for 30 - 40 psi max so high pressure could damage a fitting.


If you have an open valve I bet you have less than 20 psi in the line. You might even be as low as 10 psi.

It doesn't take much pressure to move a little water out a faucet that is wide open.